International Journal of Pharmaceutics (v.477, #1-2)

Nano-extrusion: A promising tool for continuous manufacturing of solid nano-formulations by Ramona Baumgartner; Andreas Eitzlmayr; Nadejda Matsko; Carolin Tetyczka; Johannes Khinast; Eva Roblegg (1-11).
Display OmittedSince more than 40% of today’s drugs have low stability, poor solubility and/or limited ability to cross certain biological barriers, new platform technologies are required to address these challenges. This paper describes a novel continuous process that converts a stabilized aqueous nano-suspension into a solid oral formulation in a single step (i.e., the NANEX process) in order to improve the solubility of a model drug (phenytoin). Phenytoin nano-suspensions were prepared via media milling using different stabilizers. A stable nano-suspension was obtained using Tween® 80 as a stabilizer. The matrix material (Soluplus®) was gravimetrically fed into the hot melt extruder. The suspension was introduced through a side feeding device and mixed with the molten polymer to immediately devolatilize the water in the nano-suspension. Phenytoin nano-crystals were dispersed and embedded in the molten polymer. Investigation of the nano-extrudates via transmission electron microscopy and atomic force microscopy showed that the nano-crystals were embedded de-aggregated in the extrudates. Furthermore, no changes in the crystallinity (due to the mechanical and thermal stress) occurred. The dissolution studies confirmed that the prepared nano-extrudates increased the solubility of nano-crystalline phenytoin, regardless of the polymer. Our work demonstrates that NANEX represents a promising new platform technology in the design of novel drug delivery systems to improve drug performance.
Keywords: Phenytoin nano-suspension; Hot melt extrusion; One-step continuous process; Solid nano-formulation; Nano-extrusion (NANEX);

Display OmittedNanoparticles based on naturally-occurring biopolymers, most of them endogenous macromolecules, were designed as a versatile generation of delivery platforms for delicate bioactive molecules. The design of these nanosystems was specifically based on our recent finding about the ability of endogenous polyamine spermine (SPM) to interact with anionic biopolymers (ABs) generating ionically cross-linked nanosystems.The initial first generation of these delivery platforms, based on glycosaminoglycans and other polysaccharides, showed a very high association capacity for some delicate bioactive proteins such as growth factors, but a limited capacity to associate negatively charged molecules, such as pDNA and siRNA. However, the versatility of these nanosystems in terms of composition allowed us to customise the association of active ingredients and their physicochemical characteristics. Concretely, we prepared and incorporated gelatine cationized with spermine (CGsp) to their composition. The resulting modified formulations were characterised by a nanometric size (150–340 nm) and offer the possibility to modulate their zeta potential (from −35 to 28 mV), providing an efficient association of nucleic acids. The biological evaluation of these optimised nanosystems revealed that they are able to be internalised in vivo into corneal and conjunctival tissues and also to provide a significant siRNA gene silencing effect.
Keywords: Spermine; Polyanionic biopolymers; Nanoparticles; Cationized gelatine; siRNA; Gene therapy;

Display OmittedTherapeutic efficacy of some orally administered molecules is often conditioned by their solubility in physiological fluids as well as their absorption. The last aspect becomes more limitative and conditioning drug plasmatic profiles when the active ingredient is preferentially absorbed in a specific region of the gastrointestinal tract. A case is represented by furosemide (FURO) preferentially absorbed in the stomach, site in which, because of its acidic nature, is poorly soluble. To solve this problem new oral solid formulations have been developed. The inorganic–organic hybrid MgAl-HTlc-FURO has been formulated in tablet in which floating and mucoadhesion properties have been combined. Swellable (Methocel K4, Methocel K15, Methocel K100 M, hydroxypropyl methyl cellulose) or swellable/erodible polymers (Methocel E50 LV, Methocel K100 LV), used to obtain the floating, were combined to Carbopol® (971P or 974P) to confer mucoadhesion capacity. Prepared tablets were deeply characterized in terms of hydration capacity, erosion %, buoyancy lag time/floating time and mucoadhesion. The most suitable tablets selected from these preliminary tests, submitted to in vitro release studies, showed a sustained release of FURO. This is useful to maintain the therapeutic concentrations for a long time, in comparison to conventional dosage forms, thanking to the enhancement of formulation residence time in the stomach.
Keywords: Inorganic–organic hybrids; Mucoadhesion; Floating; Gastric retention; Sustained release;

­Study of quality and stability of ursodeoxycholic acid formulations for oral pediatric administration by A. Santoveña; E. Sánchez-Negrín; L. Charola; M. Llabrés; J.B. Fariña (32-38).
Display OmittedThis paper describes a rational method of characterizing the biopharmaceutical stability of two oral suspensions of ursodeoxycholic acid (UDCA) used in pediatrics. Because there is no commercial presentation of UDCA that can administer appropriate doses for infants and children, an active pharmaceutical ingredient (API) formulation is required. Due to its very low solubility and low dose in the formula (1.5%), two different suspensions with minimal use of excipients were studied, avoiding the use of complex additives and those not recommended by the European Medicines Agency (EMA). Adherence to Standard Operating Procedure (SOP) allows the preparation of formulations with appropriately sized and stable particles, and suitable rheological behavior in withdrawing the dose after stirring. Dose uniformity, expressed as mass and content variability, was determined using the criteria of the European and the United States Pharmacopoeia. Additionally, dose content variation of every mass determined was studied. A rational method was developed for determining the dose uniformity of UDCA in suspensions, whether freshly prepared or after storage under different conditions for 30 and 60 days. This method permits detection of differences between doses taken at different heights in the vessel at various times and storage conditions. UDCA was stable under all conditions studied, requiring the presence of glycerol in the formulation to obtain the declared API value after stirring. Storage of UDCA suspensions in a refrigerator increased variability between doses.
Keywords: Ursodeoxycholic acid oral suspension; Pediatric administration; Standard Operating Procedure; Dose uniformity; Stability;

Optimization of long circulating mixed polymeric micelles containing vinpocetine using simple lattice mixture design, in vitro and in vivo characterization by Rania Moataz El-Dahmy; Ibrahim Elsayed; Ahmed Hassen Elshafeey; Nabaweya Abdelaziz Abd El Gawad; Omaima Naim El-Gazayerly (39-46).
Display OmittedThe aim of this study was to increase the in vivo mean residence time of vinpocetine after IV injection utilizing long circulating mixed micellar systems. Mixed micelles were prepared using Pluronics L121, P123 and F127. The systems were characterized by testing their entrapment efficiency, particle size, polydispersity index, zeta potential, transmission electron microscopy and in vitro drug release. Simple lattice mixture design was planned for the optimization using Design-Expert® software. The optimized formula was lyophilized, sterilized and imaged by scanning electron microscope. Moreover, the in vivo behavior of the optimized formula was evaluated after IV injection in rabbits. The optimized formula, containing 68% w/w Pluronic L121 and 32% w/w Pluronic F127, had the highest desirability value (0.621). Entrapment efficiency, particle size, polydispersity index and zeta potential of the optimized formula were 50.74 ± 3.26%, 161.50 ± 7.39 nm, 0.21 ± 0.03 and −22.42 ± 1.72 mV, respectively. Lyophilization and sterilization did not affect the characteristics of the optimized formula. Upon in vivo investigation in rabbits, the optimized formula showed a significantly higher elimination half-life and mean residence time than the market product. Finally, mixed micelles could be considered as a promising long circulating nanocarrier for lipophilic drugs.
Keywords: Pluronic; Vinpocetine; Micelles; Lyophilization; Sterilization; Vivo; Mean residence time;

Display OmittedThe objective of the present study was to prepare and evaluate a ropivacaine-loaded microemulsion (ME) formulation and microemulsion-based Carbopol gel (ME-gel) for transdermal delivery. Pseudo-ternary phase diagrams and a simplex lattice experiment design were utilized to screen and optimize the ME formulation. In the process, drug solubility and particle size were inspected as dependent variables whilst Capryol® 90 (X 1), Smix (X 2, Labrasol®: absolute ethanol = 1:2 w/w), water (X 3) as independent variables. Following the optimization, the optimal ME formulation was comprised of 15% Capryol® 90, 53% Smix, and 32% water, respectively. Ropivacaine loaded ME appeared to be spherical under transmission electron microscope, and the average particle size was 58.79 nm. The results of ex vivo permeation study showed that ropivacaine had a significant higher cumulative amount from ME than that from ME-gel. Histopathology study elucidated that the microstructure of skin surface was significantly changed by the treatment of ME formulation. Skin irritation study indicated that neither ME nor ME-gel caused any irritation responses. Both ME and ME-gel presented a remarkable analgesic activity on acetic acid-induced writhing in mice. In conclusion, ME could be a promising formulation for ropivacaine transdermally administration.
Keywords: Ropivacaine; Microemulsion; Carbopol; Transdermal delivery; Analgesic activity;

Geometry of modified release formulations during dissolution—Influence on performance of dosage forms with diclofenac sodium by Przemysław Dorożyński; Piotr Kulinowski; Witold Jamróz; Ewelina Juszczyk (57-63).
Display OmittedThe objectives of the work included: presentation of magnetic resonance imaging (MRI) and fractal analysis based approach to comparison of dosage forms of different composition, structure, and assessment of the influence of the compositional factors i.e., matrix type, excipients etc., on properties and performance of the dosage form during drug dissolution. The work presents the first attempt to compare MRI data obtained for tablet formulations of different composition and characterized by distinct differences in hydration and drug dissolution mechanisms. The main difficulty, in such a case stems from differences in hydration behavior and tablet’s geometry i.e., swelling, cracking, capping etc. A novel approach to characterization of matrix systems i.e., quantification of changes of geometrical complexity of the matrix shape during drug dissolution has been developed. Using three chosen commercial modified release tablet formulations with diclofenac sodium we present the method of parameterization of their geometrical complexity on the base of fractal analysis. The main result of the study is the correlation between the hydrating tablet behavior and drug dissolution – the increase of geometrical complexity expressed as fractal dimension relates to the increased variability of drug dissolution results.
Keywords: Diclofenac sodium; Modified release; Magnetic resonance imaging; MRI; Fractal dimension;

Display OmittedBiodegradable injectable in-situ forming implants (ISFI) correspond to an alternative parenteral depot system to microspheres and surgical implants. Objective of present work was to formulate and evaluate long acting implant of asenapine maleate (ASM) using PLGA which would release drug uniformly for 21 days. PLGA 50:50 with different drug: polymer ratios were tried. N-methyl-2-pyrrolidone and dimethyl sulphoxide were used as organic solvents. The influence of various parameters viz. polymer concentration, solvent ratio, viscosity and morphology on formation of implant was investigated. In-vitro dissolution studies indicated that drug: polymer ratio of 1:2 and N-methyl-2-pyrrolidone (0.3 ml) gave desired release profile, total cumulative drug released being 97.66% at the end of 21 days. Mathematical models point towards erosion mechanism with zero order kinetics. Ex-vivo studies confirmed the formation of implant in extensor digitorum muscle with desired drug release profile. In-vivo study was performed in Sprague– Dawley rats. Compared to marketed sublingual formulation area under curve of ASM implant was found to increase 2.215 fold. The C max was found to be 11 ng/ml. Thus long acting ISFI of ASM was successfully formulated showing improved therapeutic results for the treatment of schizophrenia and bipolar disorders which could be a potentialsubstitute to marketed sublingual tablets.
Keywords: Asenapine maleate; In-situ forming implant; PLGA; Schizophrenia; Bioavailability;

Display OmittedThe objective was to quantify drug loss due to cold flow (CF) in marketed estradiol transdermal drug delivery systems (TDDS), and study its influence on the in vitro flux and drug transfer across contacting skin. TDDS samples (products-A and B) were induced with CF at 25 and 32 °C/60% RH by applying 1-kg force for 72 h. CF was measured as percent dimensional change and amount of drug loss/migration in CF region. In vitro drug permeation studies were conducted across human epidermis from TDDS excluding CF region, and CF region alone against control (without CF). In both products, significantly higher percentage of CF (dimensional change and drug migration) was observed at 32 °C compared to 25 °C. In vitro flux from both products excluding CF region either at 25 or 32 °C was the same, but significantly lower compared to control. Drug transferred from CF region of product-A after 8 h was the same at 25 and 32 °C, but significantly higher in product-B. Flux from both products together with CF region at 32 °C was significantly lower than that observed at 25 °C. Results showed that excessive CF at storage (25 °C) and clinical usage (32 °C) conditions may have implications on product performance and safety of estradiol TDDS.
Keywords: Cold flow; Transdermal; Flux; In vitro permeation; Human epidermis; Estradiol;

Display OmittedSpheronization is an important pharmaceutical manufacturing technique to produce spherical agglomerates of 0.5–2 mm diameter. These pellets have a narrow size distribution and a spherical shape. During the spheronization process, the extruded cylindrical strands break in short cylinders and evolve from a cylindrical to a spherical state by deformation and attrition/agglomeration mechanisms. Using the discrete element method, an integrated modeling-experimental framework is presented, that captures the particle motion during the spheronization process. Simulations were directly compared and validated against particle image velocimetry (PIV) experiments with monodisperse spherical and dry γ-Al2O3 particles.demonstrate a characteristic torus like flow pattern, with particle velocities about three times slower than the rotation speed of the friction plate. Five characteristic zones controlling the spheronization process are identified: Zone I, where particles undergo shear forces that favors attrition and contributes material to the agglomeration process; Zone II, where the static wall contributes to the mass exchange between particles; Zone III, where gravitational forces combined with particle motion induce particles to collide with the moving plate and re-enter Zone I; Zone IV, where a subpopulation of particles are ejected into the air when in contact with the friction plate structure; and Zone V where the low poloidal velocity favors a stagnant particle population and is entirely controlled by the batch size.These new insights in to the particle motion are leading to deeper process understanding, e.g., the effect of load and rotation speed to the pellet formation kinetics. This could be beneficial for the optimization of a manufacturing process as well as for the development of new formulations.

Investigation of a nanosuspension stabilized by Soluplus® to improve bioavailability by Hua Yang; Fei Teng; Puxiu Wang; Bin Tian; Xia Lin; Xi Hu; Ling Zhang; Keru Zhang; Yu Zhang; Xing Tang (88-95).
Display OmittedThe purpose of this work was to explore the feasibility of using Soluplus® in preparing a fenofibrate (FBT) nanosuspension adopting wet media milling technology. HPMC and Soluplus® were used as stabilizers to prepare FBT/HPMC nanosuspension (F1) and FBT/Soluplus® nanosuspension (F2), respectively. The nanosuspensions were subjected to evaluations involving particle size, dissolution, preliminary stability and pharmacokinetic behavior. A marked reduction in particle size was achieved by nanosuspensions (from 17.55 μm to 642 nm (F1) and 344 nm (F2)). The nanosuspensions displayed almost complete dissolution while percentages of 30% and 13% were obtained by physical mixtures and coarse FBT separately. Soluplus® could stabilize the nanosuspension more effectively due to a weaker Ostwald ripening effect resulting from a slower diffusion of micelles formed by Soluplus® entrapping dissolved FBT than FBT exposed to pure water directly. In the in vivo evaluation, larger AUC0–72 h and C max, and shorter T max were obtained by the nanosuspensions. Significant differences were observed between the physical mixtures. The phenomenon of double peaks was present in this study. The major factor may be the multiple absorption sites of FBT. The current work indicated that Soluplus® is well suited for preparation of a nanosuspension with good stability and improved dissolution and bioavailability.
Keywords: Soluplus®; Nanosuspension; Stability; Wet media milling; Fenofibrate; Bioavailability;

Intranasal delivery of liposomal indole-3-carbinol improves its pulmonary bioavailability by Jung Min Song; Ameya R. Kirtane; Pramod Upadhyaya; Xuemin Qian; Silvia Balbo; Fitsum Teferi; Jayanth Panyam; Fekadu Kassie (96-101).
Display OmittedIndole-3-carbinol (I3C), a constituent of commonly consumed Brassica vegetables, has been shown to have anticancer effects in a variety of preclinical models of lung cancer. However, it has shown only limited efficacy in clinical trials, likely due to its poor oral bioavailability. Intranasal administration of I3C has the potential to enhance the pulmonary accumulation of the drug, thereby improving its availability at the target site of action. In this study, we developed a liposomal formulation of I3C and evaluated its lung delivery and chemopreventive potential in tobacco smoke carcinogen [4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK)]-treated mice. Intranasal administration of I3C liposomes led to a ∼100-fold higher lung exposure of I3C than the oral route of administration. Further, intranasal delivery of liposomal I3C led to a significant reduction (37%; p  < 0.05) in the levels of the DNA adduct formation induced by NNK treatment. Liposomal I3C also significantly increased (by 10-fold) the expression of CYP1A1, a cytochrome P450 enzyme known to increase the detoxification of chemical carcinogens by enhancing their metabolism. Overall, our findings demonstrate that intranasal administration of liposomal I3C has the potential to significantly improve the efficacy of I3C for lung cancer chemoprevention.
Keywords: Liposomes; Indole-3-carbinol; 4-(Methylnitro-samino)-1-(3-pyridyl)-1-butanone; Cytochrome P450 1A1; DNA adduct; O 6-Methylguanine DNA adduct;

Display OmittedThe principal aim of this work was to study the formulation of a ternary complex comprising salmon calcitonin (sCT), hyaluronate (HA), and chitosan (CS) in a nanoparticle (NP) format. As interactions between the constituents are possible, their presence and component mass mixing ratio (MMR) and charge mixing ratio (CMR) were investigated to tune the properties of NPs.Intermolecular interactions between sCT and HA as well as sCT and CS were studied by infrared spectroscopy (FTIR) and dynamic viscosity. The impact of MMR, CMR, and HA molecular weight on the sCT loading capacity in NPs and in vitro release properties was determined.sCT complexes to HA via electrostatic interactions and a support for hydrophobic interactions between sCT and HA as well as sCT and CS was found by FTIR. The sCT/HA complex is soluble but, depending on the mass mixing ratio between sCT and HA, NPs and microparticles were also formed indicative of associative phase separation between HA and sCT. The negatively charged HA/CS/sCT NPs were characterized by very high values (above 90%) of peptide association for the systems tested. Also, high sCT loading up to 50% were achieved. The peptide loading capacity and in vitro release properties were dependent on the NP composition. The zeta potential of the NPs without sCT was negative and ranging from −136 to −36 mV, but increased to −84 to −19 mV when the peptide was loaded. The particle size was found to be smaller and ranging 150–230 nm for sCT/NPs in comparison to NPs without sCT (170–260 nm). Short-term storage studies in liquid dispersions showed that the colloidal stability of NPs was acceptable and no release of sCT was observed for up to 3 days.In conclusion, a range of NP systems comprising sCT, HA, and CS was successfully developed and characterized. Such NPs may be considered as a suitable nanoparticulate format for the delivery of sCT.
Keywords: Hyaluronate; Chitosan; Salmon calcitonin; Nanoparticles; Polyelectrolyte complex; In vitro release;

Antibacterial properties of laser spinning glass nanofibers by M.M. Echezarreta-López; T. De Miguel; F. Quintero; J. Pou; M. Landin (113-121).
Display OmittedA laser-spinning technique has been used to produce amorphous, dense and flexible glass nanofibers of two different compositions with potential utility as reinforcement materials in composites, fillers in bone defects or scaffolds (3D structures) for tissue engineering. Morphological and microstructural analyses have been carried out using SEM–EDX, ATR-FTIR and TEM. Bioactivity studies allow the nanofibers with high proportion in SiO2 (S18/12) to be classified as a bioinert glass and the nanofibers with high proportion of calcium (ICIE16) as a bioactive glass. The cell viability tests (MTT) show high biocompatibility of the laser spinning glass nanofibers. Results from the antibacterial activity study carried out using dynamic conditions revealed that the bioactive glass nanofibers show a dose-dependent bactericidal effect on Sthaphylococcus aureus (S. aureus) while the bioinert glass nanofibers show a bacteriostatic effect also dose-dependent. The antibacterial activity has been related to the release of alkaline ions, the increase of pH of the medium and also the formation of needle-like aggregates of calcium phosphate at the surface of the bioactive glass nanofibers which act as a physical mechanism against bacteria.The antibacterial properties give an additional value to the laser-spinning glass nanofibers for different biomedical applications, such as treating or preventing surgery-associated infections.
Keywords: Bioactive glasses; Bioinert glasses; Biocompatibility; Antibacterial properties; Nanofibers; Laser spinning; Dynamic conditions;

Long-term stability study of Prussian blue – A quality assessment of water content and thallium binding by Adil Mohammad; Patrick J. Faustino; Mansoor A. Khan; Yongsheng Yang (122-127).
Long-term stability of Prussian blue: a comparison of thallium binding data from 2003 to 2013. Thallium binding for several Prussian blue drug products exposed to 600 ppm initial thallium concentration for 24 h at maximal binding at pH 7.5.Display OmittedThe purpose of this study is to assess the long-term stability of Prussian blue (PB) drug product (DP) and active pharmaceutical ingredient (API) under laboratory storage conditions by monitoring the loss in water content and the corresponding change of the in vitro thallium binding capacity that represents product performance. The bound water content and the in vitro thallium binding capacity of PB DPs and APIs were measured in 2003 and 2013, respectively. Water content, a critical quality attribute that directly correlates to the thallium (Tl) binding capacity was measured by thermal gravimetric analysis (TGA). The thallium binding study was conducted by testing PB in buffered solutions over the human gastrointestinal pH range with thallium concentrations ranging from 600 to 1500 ppm. Samples were incubated at physiological temperature of 37 °C in a shaking water bath to mimic gastric flux and intestinal transport. The binding equilibrium was reached at 24 h. Following incubation, each sample was filtered and the free thallium was analyzed using a validated inductively coupled plasma spectroscopic method (ICP). The Langmuir isotherm was plotted to calculate maximum binding capacity (MBC). Compared with 2003, the water content of DP-1 decreased by about 14.1% (from 15.6 to 13.4 mol), and the MBC of DP-1 decreased by about 12.5% (from 714 to 625 mg/g) at pH 7.5. When low concentration of thallium (600 ppm) was used at pH 7.5, the Tl binding remained comparable for both API-1 (286 vs 276 mg/g) and DP-1 (286 vs 268 mg/g). Similarly, the Tl binding remained unchanged for both API-1 (237 vs 255 mg/g) and DP-1 (234 vs 236 mg/g) at pH 5.0. However, at pH 1.0 the binding was reduced 32.3% and 25.9% for API-1 and DP-1, respectively. Since the majority of binding takes place in the upper GI tract where pH around 5 can be expected, and therefore, the Tl binding capacity of PB should be comparable for new and aged samples. The findings that Tl binding changes with the water loss of PB and pH conditions are consistent with our previously published data. The study also represents the first quantitative assessment of the long-term stability of PB. Over last 10 years, PB DPs and APIs have lost about 20% water under ambient laboratory storage conditions which are consistent with a controlled warehouse environment. While the maximum binding capacity of PB to thallium was decreased after about 10 years of long-term storage, it is still very effective, suggesting that the shelf life of PB should be much longer than the manufacturer ascribed expiration date of 2008 under proper storage conditions.
Keywords: Prussian blue; Thallium binding; Particle size; Water content loss; Hydration; Product quality;

Liposomes for targeting hepatocellular carcinoma: Use of conjugated arabinogalactan as targeting ligand by Sanket M. Shah; Peeyush N. Goel; Ankitkumar S. Jain; Pankaj O. Pathak; Sameer G. Padhye; Srinath Govindarajan; Sandipto S. Ghosh; Pradip R. Chaudhari; Rajiv P. Gude; Vijaya Gopal; Mangal S. Nagarsenker (128-139).
Display OmittedPresent study investigates the potential of chemically modified (Shah et al., 2013) palmitoylated arabinogalactan (PAG) in guiding liposomal delivery system and targeting asialoglycoprotein receptors (ASGPR) which are expressed in hepatocellular carcinoma (HCC). PAG was incorporated in liposomes during preparation and doxorubicin hydrochloride was actively loaded in preformed liposomes with and without PAG. The liposomal systems with or without PAG were evaluated for in vitro release, in vitro cytotoxicity, in vitro cell uptake on ASGPR+ cells, in vivo pharmacokinetic study, in vivo biodistribution study, and in vivo efficacy study in immunocompromised mice. The particle size for all the liposomal systems was below 200 nm with a negative zeta potential. Doxorubicin loaded PAG liposomes released significantly higher amount of doxorubicin at pH 5.5 as compared to pH 7.4, providing advantage for targeted tumor therapy. Doxorubicin in PAG liposomes showed superior cytotoxicity on ASGPR+ HepG2 cells as compared to ASGPR, MCF7, A549, and HT29 cells. Superior uptake of doxorubicin loaded PAG liposomes as compared to doxorubicin loaded conventional liposomes was evident in confocal microscopy studies. Higher AUC in pharmacokinetic study and higher deposition in liver was observed for PAG liposomes compared to conventional liposomes. Significantly higher tumor suppression was noted in immunocompromised mice for mice treated with PAG liposomes as compared to the conventional liposomes. Targeting ability and superior activity of PAG liposomes is established pre-clinically suggesting potential of targeted delivery system for improved treatment of HCC.
Keywords: Arabinogalactan; Doxorubicin liposome; Targeted delivery; Hepatocellular carcinoma; Asialoglycoprotein receptors; Targeted liposomes;

Use of in-die powder densification parameters in the implementation of process analytical technologies for tablet production on industrial scale by Marco Cespi; Diego R. Perinelli; Luca Casettari; Giulia Bonacucina; Giuseppe Caporicci; Filippo Rendina; Giovanni F. Palmieri (140-147).
Display OmittedThe use of process analytical technologies (PAT) to ensure final product quality is by now a well established practice in pharmaceutical industry. To date, most of the efforts in this field have focused on development of analytical methods using spectroscopic techniques (i.e., NIR, Raman, etc.). This work evaluated the possibility of using the parameters derived from the processing of in-line raw compaction data (the forces and displacement of the punches) as a PAT tool for controlling the tableting process. To reach this goal, two commercially available formulations were used, changing the quantitative composition and compressing them on a fully instrumented rotary pressing machine. The Heckel yield pressure and the compaction energies, together with the tablets hardness and compaction pressure, were selected and evaluated as discriminating parameters in all the prepared formulations.The apparent yield pressure, as shown in the obtained results, has the necessary sensitivity to be effectively included in a PAT strategy to monitor the tableting process. Additional investigations were performed to understand the criticalities and the mechanisms beyond this performing parameter and the associated implications.Specifically, it was discovered that the efficiency of the apparent yield pressure depends on the nominal drug title, the drug densification mechanism and the error in pycnometric density.In this study, the potential of using some parameters derived from the compaction raw data has been demonstrated to be an attractive alternative and complementary method to the well established spectroscopic techniques to monitor and control the tableting process. The compaction data monitoring method is also easy to set up and very cost effective.
Keywords: Heckel; Yield pressure; PAT; QbD; Tablets; Compression;

Display OmittedThis study selected γ-cyclodextrin (γ-CD) as the inclusion material and prepared inclusion complex of taxifolin-γ-CD by the emulsion solvent evaporation and the freeze drying combination method to achieve the improvement of the solubility and oral bioavailability of taxifolin. We selected ethyl acetate as the oil phase, deionized water as the water phase. The taxifolin emulsion was prepared using adjustable speed homogenate machine in the process of this experiment, whose particle size was related to the concentration of taxifolin solution, the volume ratio of water phase to oil phase, the speed and time of homogenate. We knew through the single-factor test that, the optimum conditions were: the concentration of taxifolin solution was 40 mg/ml, the volume ratio of water phase to oil phase was 1.5, the speed of homogenate was 5000 rpm, the homogenate time was 11 min. Taxifolin emulsion with a MPS of 142.5 nm was obtained under the optimum conditions, then the high-concentration taxifolin solution (3 mg/ml) was obtained by the rotary evaporation process. Finally, the inclusion complex of taxifolin-γ-CD was prepared by vacuum freeze-dry. The characteristics of the inclusion complex of taxifolin-γ-CD were analyzed using SEM, FTIR, XRD, DSC, and TG. The FTIR results analyzed the interaction of taxifolin and γ-CD and determined the molecular structure of the inclusion complex of taxifolin-γ-CD. The analysis results of XRD, DSC and TG indicated that the inclusion complex of taxifolin-γ-CD was obtained and showed significantly different characteristics with taxifolin. In addition, dissolving capability test, antioxidant capacity test, solvent residue test were also carried out. The experimental datas showed that the solubility of inclusion complex of taxifolin-γ-CD at 25 °C and 37 °C were about 18.5 times and 19.8 times of raw taxifolin, the dissolution rate of inclusion complex of taxifolin-γ-CD were about 2.84 times of raw taxifolin, the bioavailability of inclusion complex of taxifolin-γ-CD increased 3.72 times compared with raw taxifolin, and the antioxidant capacity of inclusion complex of taxifolin-γ-CD was also superior to raw taxifolin. Furthermore, the amounts of residual solvent of the inclusion complex of taxifolin-γ-CD were suitable for pharmaceutical use. These results suggested that inclusion complex of taxifolin-γ-CD may have potential value to become a new oral taxifolin formulation with high solubility.
Keywords: Taxifolin; Inclusion complex; Emulsion solvent evaporation method; Freeze drying method; Solubility; Bioavailability;

Display OmittedThe therapeutic efficacy of repaglinide (RPG) is limited by the low and variable oral bioavailability owing to its limited aqueous solubility. In our present study, the development and evaluation of inclusion complex applying hydroxypropyl-β-cyclodextrin (HP-β-CD) for the improvement of oral bioavailability of repaglinide was investigated systematically. The inclusion complex of repaglinide was prepared by lyophilization technique using drug: hydroxypropyl-β-cyclodextrin (1:15 mole). The prepared complexation was characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), NMR spectroscopy and evaluated by dissolution studies. The 1H NMR was used in the structure study of repaglinide-HP-β-CD (RPG-HP-β-CD) inclusion complex. The analysis proved the higher probability of the repaglinide A-ring into the narrow rim of the β-cyclodextrin molecule. All the characterization information confirmed the formation of RPG-HP-β-CD inclusion complex. The in vivo pharmacokinetics of RPG-HP-β-CD and their physical mixture were performed in beagle dogs. For the first time, a simple, rapid, and sensitive LC–MS/MS method for determination of RPG in beagle dog plasma was developed. The C max and AUC0−t of RPG-HP-β-CD were 2.5 and 2 times higher than that of the physical mixture. These results suggested that the interaction of repaglinide with HP-β-CD could notably improve the dissolution rate and bioavailability of repaglinide comparing with its physical mixture.
Keywords: Repaglinide; Hydroxypropyl-; β-cyclodextrin; Inclusion complex; NMR spectroscopy; Phase solubility studies; Pharmacokinetics;

Display OmittedPentamidine is an effective antiparasitic agent and approved drug for the treatment of African trypanosomiasis (sleeping sickness). However, pentamidine suffers from poor orally bioavailability and lacks central nervous system (CNS) delivery. Therefore its applicability is limited to intravenous or intramuscular treatment of the first stage of the African trypanosomiasis. For this reason, several new pentamidine pro-drugs have been developed with the aim of providing improved orally availability and CNS penetration.this work aims to measure and to compare the distribution, bioavailability, and ability to cross the blood–brain barrier of [123I]-labeled pentamidine and its pro-drugs, N,N′-dihydroxypentamidine and N,N′‑bis(succinyloxy) pentamidine, using SPECT (single photon emission computed tomography) after intravenously and per orally administration in rats.a total of 60 male Sprague Dawley rats were examined. Each [123I]-labeled substance (n  = 3) was applied to 12 rats (n  = 6 i.v. and n  = 6 orally). In two additional test series both [123I]iodopentamidine (n  = 6) and N,N -bis(succinyloxy)-[123I]iodopentamidine (n  = 6) were administered orally together with the non-radioactive homologues. To evaluate the in vivo stability of the labeled compounds, [123I]NaI solution was administered intravenously (n  = 6) and orally (n  = 6). In vivo SPECT images were acquired after 30 min, 4 h, and 24 h and blood samples were taken over 24 h. The SPECT images were fusioned with previously acquired magnetic resonance images. After the last SPECT the rats were perfused, sacrificed and the organ γ-radiation levels were determined with a γ-counter. Analysis and quantification of the reconstructed SPECT images was performed using the region of interest technique.the data showed a highly improved oral bioavailability of the [123I]-labeled pro-drugs compared to [123I]-labeled pentamidine. While [123I]iodopentamidine was mainly renally eliminated the pro-drugs were primarily metabolized in the liver and underwent biliary elimination. Considering pentamidine’s nephrotoxicity this feature has to be seen as an advantage of the pro-drug principle. Moreover, a significantly higher concentration in the brain was detected after intravenous injection of N,N-dihydroxy[123I]iodopentamidine compared to [123I]iodopentamidine. The feasibility of an effective treatment of second stage African trypanosomiasis, in which the parasites already infected the brain, with the herein investigated pro-drugs remains to be clarified with infected animals in additional in vivo studies.
Keywords: Pentamidine; Pro-drug; SPECT-imaging; Bioavailibility;

Development of novel diolein–niosomes for cutaneous delivery of tretinoin: Influence of formulation and in vitro assessment by Maria Letizia Manca; Maria Manconi; Amparo Nacher; Claudia Carbone; Donatella Valenti; Anna Maria Maccioni; Chiara Sinico; Anna Maria Fadda (176-186).
Display OmittedThis work describes innovative niosomes, composed of diolein alone or in association with the hydrophilic penetration enhancer Labrasol®, as carriers for cutaneous drug delivery. The model drug was tretinoin and conventional, and Labrasol® containing liposomes was used as controls to evaluate the influence of vesicle composition and the role of Labrasol® on vesicle physico-chemical properties and performance as skin delivery system.Vesicles, prepared by the thin film hydration technique, were characterized in terms of size distribution, morphology, zeta potential, structure, incorporation efficiency, and rheological properties. The influence of carrier composition on tretinoin delivery to human skin was evaluated by in vitro percutaneous experiments, while formulation distribution on human skin and cellular uptake in human keratinocytes were studied using confocal laser scanning microscopy.showed that tretinoin loaded diolein–niosomes formed unilamellar vesicles very similar in physico-chemical properties to liposomes. The role of Labrasol® was similar in niosomes and liposomes. Its addition affected vesicle structure and size, by formation of an interdigitate bilayer with higher curvature and larger vesicle size, and rheological properties. Indeed, the presence of Labrasol® allowed both niosomes and liposomes to shift from Newtonian to pseudo-plastic behavior.Confocal laser microscopy highlighted an important contemporaneous deposition of hydrophilic and lipophilic vesicle components in stratum corneum and a high vesicle affinity for skin appendages when Labrasol® was added to the diolein–niosomes. Moreover, all samples were internalized in human keratinocytes in vitro.
Keywords: Niosomes; Labrasol®; Tretinoin; Confocal laser scanning microscopy; Skin delivery; SAXS;

Hepatoma-targeting and pH-sensitive nanocarriers based on a novel d-galactopyranose copolymer for efficient drug delivery by Yuanyuan Ding; Jingtian Han; Baocheng Tian; Jian Han; Jing Zhang; Hong Zheng; Yuzhen Han; Meishan Pei (187-196).
Novel multi-functional polymeric nanoparticles composed of methoxy-polyethylene glycols (PEG)-b-poly (d-galactopyranose) (MPEG-b-PMaIPG) were prepared to carry doxorubicin for hepatoma targeting and pH triggered drug delivery.Display OmittedSmart nanoparticles based on the mechanisms of asialoglycoprotein (ASGP)-mediated endocytosis and pH-induced drug release were developed for the efficient treatment of hepatoma using a newly developed copolymer, methoxy-polyethylene glycols (PEG)-b-poly (d-galactopyranose) (MPEG-b-PMaIPG). The particles exhibited spherical shapes, uniform particle size distribution (100 ± 4.43 nm), negative zeta potential (−32.8 ± 0.23 mV), high drug loading (24.77 ± 2.68%) and encapsulation efficiency (66.12 ± 9.44%). The in vitro drug release was also investigated, resulting that the release of drug from particles depended on different pH value. In vitro cell cytotoxicity and hemolysis assays were conducted to confirm the safety of the MPEG-b-PMaIPG nanoparticles. Anticancer activity showed that DOX-loaded MPEG-b-PMaIPG nanoparticles exhibited a high antitumor activity toward HepG2 cells, which was similar to free DOX, while blank MPEG-b-PMaIPG nanoparticles were non-toxic up to a tested concentration of 1.0 mg/mL. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to verify the targeting efficiency of d-galactopyranose-modified nanoparticles. The results clearly demonstrated that d-galactopyranose-modified nanoparticles were taken up quickly by the HepG2 cells, which suggests that MPEG-b-PMaIPG nanoparticles with good biocompatibility and non-toxic for normal cells may be used as an effective cancer-targeting drug delivery system for chemotherapy.
Keywords: Hepatoma-targeting; pH-sensitive; Drug delivery; d-Galactopyranose; Nanoparticles;

Polyelectrolyte complexes of poly[(2-dimethylamino) ethyl methacrylate]/chondroitin sulfate obtained at different pHs: I. Preparation, characterization, cytotoxicity and controlled release of chondroitin sulfate by Letícia C. Bonkovoski; Alessandro F. Martins; Ismael C. Bellettini; Francielle P. Garcia; Celso V. Nakamura; Adley F. Rubira; Edvani C. Muniz (197-207).
Display OmittedFor the first time, polyelectrolyte complex based on poly[(2-dimethylamino) ethyl methacrylate] (PDMAEMA) and chondroitin sulfate (CS) was prepared. The properties of novel material and precursors were investigated by WAXS, FTIR, TGA, SEM and DLS analysis. The PDMAEMA/CS PECs presented hydrophilic–hydrophobic transition at pHs 6.0, 7.0 and 8.0 whereas the non-complexed PDMAEMA showed such a transition at pH 8.0 and not at pHs 6.0 and 7.0. Studies of CS release from PECs at pHs 6 and 8 confirmed that the samples possess the potential to release the CS in alkaline and not in acidic conditions. Since PECs are thermo-responsive due to the reduction of LCST caused by the increase in pH, the release of CS was dependent on temperature and pH factors. Cytotoxicity assays using healthy VERO cells showed that the complexation between CS and PDMAEMA increased the PECs' biocompatibility related to PDMAEMA. However, the biocompatibility depends on the amount of CS present in the PECs.
Keywords: Poly[(2-dimethylamino) ethyl methacrylate]; Chondroitin sulfate; Polyelectrolyte complexes; release; Cytotoxicity;

Development of artemether-loaded nanostructured lipid carrier (NLC) formulation for topical application by Petra O. Nnamani; Steffi Hansen; Maike Windbergs; Claus-Michael Lehr (208-217).
Artemether is thermostable at 90–95 °C, so has been stably formulated in well selected nanostructured lipid carriers as an alternative sustained release topical regimen devoid of the drug’s extensive nausea–vomiting effect which majorly account for patient non-compliance aside from some contra-indications. Ex vivo study has shown that ART permeates through human excised skin which is known to mimic permeation in vivo.Display OmittedNLC topical formulation as an alternative to oral and parenteral (IM) delivery of artemether (ART), a poorly water-soluble drug was designed. A Phospholipon 85G-modified Gelucire 43/01 based NLC formulation containing 75% Transcutol was chosen from DSC studies and loaded with gradient concentration of ART (100–750 mg). ART-loaded NLCs were stable (−22 to −40 mV), polydispersed (0.4–0.7) with d90 size distribution range of 247–530 nm without microparticles up to one month of storage. The encapsulation efficiency (EE%) for ART in the NLC was concentration independent as 250 mg of ART loading achieved ∼61%. DSC confirmed molecular dispersion of ART due to low matrix crystallinity (0.028 J/g). Ex vivo study showed detectable ART amounts after 20 h which gradually increased over 48 h achieving ∼26% cumulative amount permeated irrespective of the applied dose. This proves that ART permeates excised human epidermis, where the current formulation served as a reservoir to gradually control drug release over an extended period of time. Full thickness skin study therefore may confirm if this is a positive signal to hope for a topical delivery system of ART.
Keywords: Malaria; Artemether; Nanostructured lipid carrier; Particle characterization; Ex vivo skin permeation; Topical formulation;

New drug-eluting lenses to be applied as bandages after keratoprosthesis implantation by A.S. Carreira; P. Ferreira; M.P. Ribeiro; T.R. Correia; P. Coutinho; I.J. Correia; M.H. Gil (218-226).
Display OmittedCorneal tissue is the most commonly transplanted tissue worldwide. This work aimed to develop a new drug-eluting contact lens that may be used as a bandage after keratoprosthesis. During this work, films were produced using poly(vinyl alcohol) (PVA) and chitosan (CS) crosslinked with glyoxal (GL). Vancomycin chlorhydrate (VA) was impregnated in these systems by soaking. Attenuated total reflectance – Fourier transform infrared spectroscopy was used to confirm crosslinking. The cytotoxic and drug release profile, hydrophilicity, thermal and biodegradation as well as swelling capacity of the samples were assessed through in vitro studies. PVA and PVA/CS films were obtained by crosslinking with GL. The films were transparent, flexible with smooth surfaces, hydrophilic and able to load and release vancomycin for more than 8 h. Biodegradation in artificial lachrymal fluid (ALF) with lysozyme at 37 °C showed that mass loss was higher for the samples containing CS. Also, the samples prepared with CS showed the formation of pores which were visualized by SEM. All samples revealed a biocompatible character after 24 h in contact with cornea endothelial cells. As a general conclusion it was possible to determine that the 70PVA/30CS film showed to combine the necessary features to prepare vancomycin-eluting contact lenses to prevent inflammation after corneal substitution.
Keywords: Drug-eluting lens; Keratoprosthesis; Poly(vinyl alcohol); Chitosan; Glyoxal;

Oil-enriched, ultra-small nanostructured lipid carriers (usNLC): A novel delivery system based on flip–flop structure by Cornelia M. Keck; Nuttakorn Baisaeng; Philippe Durand; Michel Prost; Martina C. Meinke; Rainer H. Müller (227-235).
Display OmittedFor the development of ultra-small NLC (usNLC) the determination of the required HLB (hydrophilic lipophilic balance) was found to be a suitable method, i.e., usNLC with a size below 50 nm were obtained by this method. Loading with 5% (w/w) coenzyme Q10 (Q10) led to usNLC with a size of about 85 nm. In comparison to classical NLC with a size of 230 nm and a nanoemulsion with similar size, the Q10 loaded usNLC show a higher release, a higher antioxidant capacity, and a better skin penetration for Q10. The reason for this is a flip–flop core–shell structure of the lipid matrix, i.e., the oil with dissolved active is surrounding the solid lipid based core. As the flip–flop structure was probably achieved by admixing high contents of liquid lipid, oil enriched usNLC might represent a novel and promising carrier system for the improved delivery of lipophilic actives.
Keywords: Lipid nanoparticles; Nanostructured lipid carriers; Required HLB; Ultra-small NLC; Flip–flop core–shell structure; Coenzyme Q10;

A novel ibuprofen derivative with anti-lung cancer properties: Synthesis, formulation, pharmacokinetic and efficacy studies by Ka-Wing Cheng; Ting Nie; Nengtai Ouyang; Ninche Alston; Chi C. Wong; George Mattheolabakis; Ioannis Papayannis; Liqun Huang; Basil Rigas (236-243).
Display OmittedPhospho-non-steroidal anti-inflammatory drugs (phospho-NSAIDs) are a novel class of NSAID derivatives with potent antitumor activity. However, phospho-NSAIDs have limited stability in vivo due to their rapid hydrolysis by carboxylesterases at their carboxylic ester link. Here, we synthesized phospho-ibuprofen amide (PIA), a metabolically stable analog of phospho-ibuprofen, formulated it in nanocarriers, and evaluated its pharmacokinetics and anticancer efficacy in pre-clinical models of human lung cancer. PIA was 10-fold more potent than ibuprofen in suppressing the growth of human non-small-cell lung cancer (NSCLC) cell lines, an effect mediated by favorably altering cytokinetics and inducing oxidative stress. Pharmacokinetic studies in rats revealed that liposome-encapsulated PIA exhibited remarkable resistance to hydrolysis by carboxylesterases, remaining largely intact in the systemic circulation, and demonstrated selective distribution to the lungs. The antitumor activity of liposomal PIA was evaluated in a metastatic model of human NSCLC in mice. Liposomal PIA strongly inhibited lung tumorigenesis (>95%) and was significantly (p  < 0.05) more efficacious than ibuprofen. We observed a significant induction of urinary 8-iso-prostaglandin F in vivo, which indicates that ROS stress probably plays an important role in mediating the antitumor efficacy of PIA. Our findings suggest that liposomal PIA is a potent agent in the treatment of lung cancer and merits further evaluation.
Keywords: Lung cancer; Liposome; Phospho-ibuprofen amide; Ibuprofen; Xenografts;

Release characteristics of polyurethane tablets containing dicarboxylic acids as release modifiers – a case study with diprophylline by Bart Claeys; Sander De Bruyn; Laurent Hansen; Thomas De Beer; Jean Paul Remon; Chris Vervaet (244-250).
Display OmittedThe influence of several dicarboxylic acids on the release characteristics of polyurethane tablets with a high drug load was investigated. Mixtures of diprophylline (Dyph) and thermoplastic polyurethane (TPUR) (ratio: 50/50, 65/35 and 75/25 wt.%) were hot-melt extruded and injection molded with the addition of 1, 2.5, 5 and 10% wt.% dicarboxylic acid as release modifier. Incorporating malonic, succinic, maleic and glutaric acid in the TPUR matrices enhanced drug release, proportional to the dicarboxylic acid concentration in the formulation. No correlation was found between the water solubility, melting point, logP and pK a of the acids and their drug release modifying capacity. Succinic and maleic acid had the highest drug release modifying capacity which was linked to more intense molecular interactions with Dyph. A structural fit between the primary and secondary alcohol of Dyph and both carboxylic groups of the acids was at the origin of this enhanced interaction.
Keywords: Drug delivery systems; Polymers; Extrusion; Release modifier;

Effects of stabilizing agents on the development of myricetin nanosuspension and its characterization: An in vitro and in vivo evaluation by Chao Hong; Yang Dang; Guobei Lin; Yashu Yao; Guowen Li; Guang Ji; Hongyi Shen; Yan Xie (251-260).
Display OmittedAlthough myricetin has various pharmacological applications, it shows low oral bioavailability (<10%) in rats due to its poor aqueous solubility. To overcome this issue, myricetin nanosuspensions were developed and the effects of stabilizers were investigated. Based on the particle size and zeta potential, stabilizers soya lecithin, TPGS, HP-β-CD, and/or a combination thereof were used. The prepared nanosuspensions were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRD). The resulting myricetin nanosuspensions contained particles in the size range of 300–500 nm and were physically stable. Myricetin was partially transformed from crystalline to amorphous forms in the presence of different excipients after the nanosizing process. The solubility and in vitro dissolution of all myricetin nanosuspensions were greatly increased compared with those of the myricetin powder. Consequently, the relative bioavailability in rats were 2.44, 3.57, 1.61, and 2.96 for nanosuspensions stabilized with TPGS, soya lecithin, soya lecithin + TPGS, and HP-β-CD + TPGS, respectively, relative to that of the coarse myricetin. This research demonstrated that nanosuspension is a promising strategy for delivering poor water-soluble drugs such as myricetin and that stabilizers played a critical role in the formulation design of myricetin nanosuspensions.
Keywords: Myricetin; Nanosuspension; Stabilizer; Solubility; Bioavailability;

Synthesis and anticervical cancer activity of novel pH responsive micelles for oral curcumin delivery by Warayuth Sajomsang; Pattarapond Gonil; Somsak Saesoo; Uracha Rangsadthong Ruktanonchai; Wanwisa Srinuanchai; Satit Puttipipatkhachorn (261-272).
Display OmittedCurcumin (CM) has demonstrated safety and efficacy as a drug, but its pharmaceutical role is restricted as a result of extremely low aqueous solubility, rapid systemic elimination, inadequate tissue absorption and degradation at alkaline pH; properties that severely curtail its bioavailability. To address this issue, CM was encapsulated within pH responsive amphiphilic chitosan, resulting in the formation of 100 nm spontaneously self-assembled polymeric micelles in water. The amphiphilic chitosan, namely N-benzyl-N,O-succinyl chitosan (BSCS), was prepared by reductive N-benzylation and N,O-succinylation. The stability of micelles after being re-dispersed in water was investigated using glycine as a cryoprotectant, and the average sizes were shown to be maintained at a level lower than 200 nm for up to 4 months, at temperatures of 4 °C and 25 °C. In vitro drug release results showed that CM was slowly released from the micelles without any burst effect in the intestine (pH 5.5–7.4), with limited release in the stomach (pH 1.2). Cytotoxicity assays indicated that CM loaded micelles showed half maximal inhibitory concentrations (IC50) 4.7-, 3.6-, and 12.2-fold lower than that of free CM in HeLa, SiHa and C33a cervical cell lines, respectively. Cellular uptake of micelles was confirmed by confocal laser scanning microscopy and flow cytometry, with a 6-fold significant increase in the amount of CM loaded micelles compared to free CM in all cervical cancer cells. Notably, CM loaded micelles promoted an increase (30–55%) in the percentage of early apoptosis of HeLa, SiHa and C33a cells, compared to free CM. These results suggest that BSCS micelles may be a promising carrier for effective oral delivery of CM.
Keywords: Chitosan; pH responsive micelles; Anticervical cancer activity; Curcumin; Drug delivery system;

Protein release from electrospun nonwovens: Improving the release characteristics through rational combination of polyester blend matrices with polidocanol by Sebastian Puhl; David Ilko; Linhao Li; Ulrike Holzgrabe; Lorenz Meinel; Oliver Germershaus (273-281).
Display OmittedNonwoven scaffolds consisting of poly-ε-caprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) and polidocanol (PD), and loaded with lysozyme crystals were prepared by electrospinning. The composition of the matrix was varied and the effect of PD content in binary mixtures, and of PD and PLGA content in ternary mixtures regarding processability, fiber morphology, water sorption, swelling and drug release was investigated. Binary PCL/PD blend nonwovens showed a PD-dependent increase in swelling of up to 30% and of lysozyme burst release of up to 45% associated with changes of the fiber morphology. Furthermore, addition of free PD to the release medium resulted in a significant increase of lysozyme burst release from pure PCL nonwovens from approximately 2–35%. Using ternary PCL/PD/PLGA blends, matrix degradation could be significantly improved over PCL/PD blends, resulting in a biphasic release of lysozyme with constant release over 9 weeks, followed by constant release with a reduced rate over additional 4 weeks. Based on these results, protein release from PCL scaffolds is improved by blending with PD due to improved lysozyme desorption from the polymer surface and PD-dependent matrix swelling.
Keywords: Protein release; Polycaprolactone; Electrospinning; Polidocanol; Lysozyme;

Antisolvent precipitation of novel xylitol-additive crystals to engineer tablets with improved pharmaceutical performance by Waseem Kaialy; Mohammad Maniruzzaman; Saeed Shojaee; Ali Nokhodchi (282-293).
Display OmittedThe purpose of this work was to develop stable xylitol particles with modified physical properties, improved compactibility and enhanced pharmaceutical performance without altering polymorphic form of xylitol. Xylitol was crystallized using antisolvent crystallization technique in the presence of various hydrophilic polymer additives, i.e., polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) at a range of concentrations. The crystallization process did not influence the stable polymorphic form or true density of xylitol. However, botryoidal-shaped crystallized xylitols demonstrated different particle morphologies and lower powder bulk and tap densities in comparison to subangular-shaped commercial xylitol. Xylitol crystallized without additive and xylitol crystallized in the presence of PVP or PVA demonstrated significant improvement in hardness of directly compressed tablets; however, such improvement was observed to lesser extent for xylitol crystallized in the presence of PEG. Crystallized xylitols produced enhanced dissolution profiles for indomethacin in comparison to original xylitol. The influence of additive concentration on tablet hardness was dependent on the type of additive, whereas an increased concentration of all additives provided an improvement in the dissolution behavior of indomethacin. Antisolvent crystallization using judiciously selected type and concentration of additive can be a potential approach to prepare xylitol powders with promising physicomechanical and pharmaceutical properties.
Keywords: Additives; Crystallization; Engineered xylitol; Indomethacin; Tableting;

Stabilization of amorphous paracetamol based systems using traditional and novel strategies by Luz María Martínez; Marcelo Videa; Gladys A. López-Silva; Carlos A. de los Reyes; Jorge Cruz-Angeles; Nahida González (294-305).
Display OmittedThere is a special interest in having pharmaceutical active ingredients in the amorphous state due to their increased solubility and therefore, higher bioavailability. Nevertheless, not all of them present stable amorphous phases. In particular, paracetamol is an active ingredient widely known for its instability when prepared in the amorphous state. In the present work thermally stable amorphous binary paracetamol based systems were obtained showing stability on a wide range of temperatures: below its glass transition temperature (T g) as amorphous solids in the glassy state and above their glass transition temperature, where these materials exist as stable supercooled liquids. To achieve stabilization of the binary paracetamol based system several strategies were applied and optimized, being the selection of the container material a key and novel approach to control the mechanical stress during cooling, eliminating cracks which act as nucleation centers leading to crystallization.
Keywords: Amorphous drugs; Paracetamol; Coamorphous; Stability; DTA; DSC;; Mechanical stress; Container;

Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.Display OmittedFlat, round tablets may have a breaking (“score”) line. Pharmacopoeial tablet breaking load tests are diametral in their design, and industrially used breaking load testers often have automatic tablet feeding systems, which position the tablets between the loading platens of the machine with the breaking lines in random orientation to the applied load. The aim of this work was to ascertain the influence of the position of the breaking line in a diametral compression test using finite element methodology (FEM) and to compare the theoretical results with practical findings using commercially produced bevel-edged, scored tablets. Breaking line test positions at an angle of 0°, 22.5°, 45°, 67.5° and 90° relative to the loading plane were studied. FEM results obtained for fully elastic and elasto-plastic tablets were fairly similar, but they highlighted large differences in stress distributions depending on the position of the breaking line. The stress values at failure were predicted to be similar for tablets tested at an angle of 45° or above, whereas at lower test angles the predicted breaking loads were up to three times larger. The stress distributions suggested that not all breaking line angles would result in clean tensile failure. Practical results, however, did not confirm the differences in the predicted breaking loads, but they confirmed differences in the way tablets broke. The results suggest that it is not advisable to convert breaking loads obtained on scored tablets into tablet tensile strength values, and comparisons between different tablets or batches should carefully consider the orientation of the breaking line with respect to the loading plane, as the failure mechanisms appear to vary.
Keywords: Bevel-edge; Brazilian equation; Breaking line; Diametral compression test; Finite element method (FEM); Tablet tensile failure;

Corneal targeted nanoparticles for sustained natamycin delivery and their PK/PD indices: An approach to reduce dose and dosing frequency by Hardik Chandasana; Yarra Durga Prasad; Yashpal S. Chhonker; Telaprolu K. Chaitanya; Nripendra N. Mishra; Kalyan Mitra; Praveen K. Shukla; Rabi S. Bhatta (317-325).
Display OmittedNatamycin is the only approved medication for the treatment of mycotic keratitis. Current dosage regimen include one drop of natamycin suspension (5% w/v) instilled in the conjunctival sac at hourly or two hourly intervals for several days which has poor patient compliance. The purpose of the present study was to design a corneal targeted nanoformulation in order to reduce dose and dosing frequency of natamycin and evaluate its pharmacokinetic/pharmacodynamic indices in comparison with clinical marketed preparation. The nanoparticles prepared by nanoprecipitation method were in nanometer size range with high entrapment efficiency and positive surface charge. In-vitro release studies indicated prolonged release of natamycin up to 8 h. In-vitro antifungal activity was comparable with marketed preparation. The performance of nanoformulations was evaluated in rabbit eyes. The concentration of natamycin in tear fluid was determined by using LC–MS/MS. The pharmacokinetic parameters such as area under the curve, t ½ and mean residence time were significantly higher and clearance was significantly lower for nanoformulations with that of marketed preparation. The optimized dosing schedule to maintain natamycin concentration above tenfold of MIC90 was one instillation in every 5 h. Moreover, 1/5th dose reduction of nanoformulation was also effective.
Keywords: Mycotic keratitis; Natamycin; Ocular drug delivery; Polycaprolactone; Nanoparticles; Pharmacokinetic/pharmacodynamic indices;

Display OmittedThe purpose of the research was to investigate the effect of moisture content of cellulose on the degradation of a drug in binary mixtures with cellulose. Physical mixtures of acetylsalicylic acid and two forms of cellulose, either microcrystalline cellulose or low crystalline cellulose, in the proportion 1:1 were stored at 50 °C at a series of relative humidities (0–90%) for up to 175 days.The degradation rate constant of the drug increased with increased cellulose moisture content in a bi-regional fashion, with a low and a high degradation rate region. The shift from region 1 to 2 occurred at higher moisture content for the low crystalline cellulose. The relationships between rate constant and the temperature of maximum endothermic value overlapped for the two celluloses. It is proposed that the amount of water available for degradation of a solid drug is controlled by the water presenting capacity of cellulose which is dependent of the mechanism of sorption of water in cellulose. The water sorption of water can for cellulose satisfactorily be described by a two-site residence model with cellulose crystallinity as the structural correlate to the distribution between the two residence sites.
Keywords: Cellulose; Crystallinity; Solid drug degradation; Moisture content; Sorption sites; Water attachment;

Acetalated dextran encapsulated AR-12 as a host-directed therapy to control Salmonella infection by Ky V. Hoang; Hassan M. Borteh; Murugesan V.S. Rajaram; Kevin J. Peine; Heather Curry; Michael A. Collier; Michael L. Homsy; Eric M. Bachelder; John S. Gunn; Larry S. Schlesinger; Kristy M. Ainslie (334-343).
Display OmittedAR-12 has been evaluated in clinical trials as an anti-cancer agent but also has demonstrated host-directed, broad-spectrum clearance of bacteria. We have previously shown that AR-12 has activity in vitro against Salmonella enterica serovar Typhimurium and Francisella species by inducing autophagy and other host immune pathways. AR-12 treatment of S. Typhimurium-infected mice resulted in a 10-fold reduction in bacterial load in the liver and spleen and an increased survival time. However, AR-12 treatment did not protect mice from death, likely due poor formulation. In the current study, AR-12 was encapsulated in a microparticulate carrier formulated from the novel degradable biopolymer acetalated dextran (Ace-DEX) and subsequently evaluated for its activity in human monocyte-derived macrophages (hMDMs). Our results show that hMDMs efficiently internalized Ace-DEX microparticles (MPs), and that encapsulation significantly reduced host cell cytotoxicity compared to unencapsulated AR-12. Efficient macrophage internalization of AR-12 loaded MPs (AR-12/MPs) was further demonstrated by autophagosome formation that was comparable to free AR-12 and resulted in enhanced clearance of intracellular Salmonella. Taken together, these studies provide support that Ace-DEX encapsulated AR-12 may be a promising new therapeutic agent to control intracellular bacterial pathogens of macrophages by targeting delivery and reducing drug toxicity.
Keywords: Autophagy; Salmonella; Macrophage; Pathogens; Microparticles; Drug resistance;

Display OmittedIn the pharmaceutical field, manufacturing processes which are able to make products with tailored size at suitable shear stress conditions and high productivity are important requirements for their industrial application. Cross-flow and premix membrane emulsification are the membrane-based processes generally used for particles preparation at large scale, however some disadvantages still limit their applicability for the production of fragile products.In this work, we investigated, for the first time, the preparation of micro and nano polymeric particles in a size range between 2.35 (±0.14) μm and 210 (±10) nm by using pulsed back-and-forward membrane emulsification for the application in pharmaceutical field. The suitability of the method to produce tailored particles by applying mild shear conditions has been demonstrated. The optimized fluid-dynamic conditions studied allowed the production of particles with target size by selecting the appropriate pore size of the membrane (1 μm and 0.1 μm). The uniformity of the particles could be obtained with an axial velocity of 0.5 ms−1 (corresponding to a shear stress of 4.1 Pa) that is 9 times lower than the maximum cross flow velocity reported in literature (4.5 ms−1).
Keywords: Polycaprolactone; Microparticles; Nanoparticles; Pulsed back-and-forward membrane Emulsification; Parenteral administration; Shirasu porous glass (SPG) membrane;

An insight into powder entrainment and drug delivery mechanisms from a modified Rotahaler® by Sally Sim; Kenneth Margo; Jonathan Parks; Ruth Howell; Gerald A. Hebbink; Laurence Orlando; Ian Larson; Philip Leslie; Louise Ho; David A.V. Morton (351-360).
Display OmittedThis study aims to improve understanding of the powder fluidisation and aerosolisation processes unique to a split capsule dry powder inhaler. It uses a combination of dynamic real-time methods and a suite of powder material physicochemical characterisation methods. The study focused on examining the effect of different characteristics of lactose carrier employed, and considered specifically the powder fluidisation, entrainment and de-agglomeration mechanisms. A GSK Rotahaler® was selected as the inhaler device. Powder fluidisation and entrainment were investigated using the ensemble technique of laser diffraction and high-speed imaging. This ensemble technique afforded both the powder entrainment profile and simultaneous visual confirmation of the capsule movement and powder fluidisation within the Rotahaler. The results showed that powder fluidisation from a dynamic split capsule was substantially different to that from a static powder bed. Furthermore, the presence of the split capsule dominated powder emission mechanisms from the Rotahaler, regulated by its impaction on the grid/Rotahaler wall and the rotational movement in the entrained air. Of all the material characterisation metrics, the most significant linear correlation was revealed between powder permeability and the aerosolisation efficiency as measured by fine particle fraction (R 2  = 0.98). This indicates that drug delivery from the Rotahaler was mainly governed by the influence of the cohesive fine particle size component. Powder permeability as a practical test may afford an effective and practical predictive link between the raw excipients and drug delivery performance from the capsule device.
Keywords: Lactose; Dry powder inhalation; Rotahaler®; Entrainment; Fluidisation; High-speed imaging;

High-throughput manufacturing of size-tuned liposomes by a new microfluidics method using enhanced statistical tools for characterization by Elisabeth Kastner; Randip Kaur; Deborah Lowry; Behfar Moghaddam; Alexander Wilkinson; Yvonne Perrie (361-368).
Display OmittedMicrofluidics has recently emerged as a new method of manufacturing liposomes, which allows for reproducible mixing in miliseconds on the nanoliter scale. Here we investigate microfluidics-based manufacturing of liposomes. The aim of these studies was to assess the parameters in a microfluidic process by varying the total flow rate (TFR) and the flow rate ratio (FRR) of the solvent and aqueous phases. Design of experiment and multivariate data analysis were used for increased process understanding and development of predictive and correlative models. High FRR lead to the bottom-up synthesis of liposomes, with a strong correlation with vesicle size, demonstrating the ability to in-process control liposomes size; the resulting liposome size correlated with the FRR in the microfluidics process, with liposomes of 50 nm being reproducibly manufactured. Furthermore, we demonstrate the potential of a high throughput manufacturing of liposomes using microfluidics with a four-fold increase in the volumetric flow rate, maintaining liposome characteristics. The efficacy of these liposomes was demonstrated in transfection studies and was modelled using predictive modeling. Mathematical modelling identified FRR as the key variable in the microfluidic process, with the highest impact on liposome size, polydispersity and transfection efficiency. This study demonstrates microfluidics as a robust and high-throughput method for the scalable and highly reproducible manufacture of size-controlled liposomes. Furthermore, the application of statistically based process control increases understanding and allows for the generation of a design-space for controlled particle characteristics.
Keywords: Liposomes; Microfluidics; Design of experiment; High-throughput manufacturing; DNA delivery;

Fast dissolving paracetamol/caffeine nanofibers prepared by electrospinning by U. Eranka Illangakoon; Hardyal Gill; Gemma C. Shearman; Maryam Parhizkar; Sunthar Mahalingam; Nicholas P. Chatterton; Gareth R. Williams (369-379).
Display OmittedA series of polyvinylpyrrolidone fibers loaded with paracetamol (PCM) and caffeine (CAF) was fabricated by electrospinning and explored as potential oral fast-dissolving films. The fibers take the form of uniform cylinders with smooth surfaces, and contain the drugs in the amorphous form. Drug–polymer intermolecular interactions were evidenced by infrared spectroscopy and molecular modeling. The properties of the fiber mats were found to be highly appropriate for the preparation of oral fast dissolving films: their thickness is around 120–130 μm, and the pH after dissolution in deionized water lies in the range of 6.7–7.2. Except at the highest drug loading, the folding endurance of the fibers was found to be >20 times. A flavoring agent can easily be incorporated into the formulation. The fiber mats are all seen to disintegrate completely within 0.5 s when added to simulated saliva solution. They release their drug cargo within around 150 s in a dissolution test, and to undergo much more rapid dissolution than is seen for the pure drugs. The data reported herein clearly demonstrate that electrospun PCM/CAF fibers comprise excellent candidates for oral fast-dissolving films, which could be particularly useful for children and patients with swallowing difficulties.
Keywords: Electrospinning; Nanofiber; Paracetamol; Caffeine; Fast-dissolving drug delivery system;

Evaluation of sorption capacity of antibiotics and antibacterial properties of a cyclodextrin-polymer functionalized hydroxyapatite-coated titanium hip prosthesis by Mariam Taha; Feng Chai; Nicolas Blanchemain; Christel Neut; Michel Goube; Mickael Maton; Bernard Martel; Hartmut F. Hildebrand (380-389).
Display OmittedInfection still present as one of common complications after total hip replacement (∼2.5%), which may cause serious outcomes. For preventing such risk, loading antibiotics onto implants for increasing local drug concentration at targeted sites could be a solution. This study aims at modifying the surface of hydroxyapatite (HA) coated titanium hip implant material (Ti–HA) with polymer of cyclodextrin (polyCD) for loading antibiotics, to achieve a sustained local drug delivery. Two widely applied antibiotics (tobramycin and rifampicin) in orthopedic surgery were loaded alone or in combination. The drug adsorption isotherm, drug release kinetics and drug’s efficacy were thoroughly investigated. The results proved that polyCD coating significantly improved the affinity of both drugs to Ti–HA surface, while the mechanism of drug–polyCD interaction varies from the nature of drug, courtesy of the structural complex of polyCD. The advantage of dual-drug loading was highlighted by its strong efficacy against both Staphylococcus aureus and Enterobacter cloacae, which overcomes the limitation of mono-drug loading for an effective treatment against both bacterial strains. The prolonged antibacterial activity of antibiotic loaded Ti–HA-polyCD samples confirmed that polyCD could be a promising drug-delivery system, for sustained antibiotics release or other potential applications e.g., antimitotic agent release.
Keywords: Hip prosthesis; Cyclodextrin; Infection; Drug delivery system; Antibiotics;

Self-nanoemulsifying drug delivery systems for oral insulin delivery: In vitro and in vivo evaluations of enteric coating and drug loading by Ping Li; Angel Tan; Clive A. Prestidge; Hanne Mørck Nielsen; Anette Müllertz (390-398).
Display OmittedThis study aims at evaluating the combination of self-nanoemulsifying drug delivery systems (SNEDDS) and enteric-coated capsules as a potential delivery strategy for oral delivery of insulin. The SNEDDS preconcentrates, loaded with insulin–phospholipid complex at different levels (0, 2.5 and 10% w/w), were readily dispersed in water to form nanoemulsions of 35 nm and vesicles of 300 nm. The association efficiency of non-complexed insulin in the dispersed SNEDDS was 18.6%, and was increased to 73.1% for insulin–phospholipid complex (at 10% loading level). The morphology of the dispersed SNEDDS changed from nanoemulsion droplets to vesicular structures with increasing complex loading levels. A pH-dependent insulin release profile was observed for SNEDDS filled into capsules coated with the enteric polymer, Eudragit® L100. Using a Caco-2 cell model, it was observed that the transport of insulin was enhanced by factors of 7.7- and 9.3- for SNEDDS loaded with 2.5 and 10% complex, respectively. In healthy fasted rats, administration of SNEDDS (10% complex) filled in enteric-coated capsules produced a 2.7-fold and 3.4-fold enhancement in the relative bioavailability and glucose reduction, respectively. This study shows the effectiveness of combining SNEDDS (loaded with insulin–phospholipid complex) with enteric-coated capsules for enhancing the oral absorption and efficacy of insulin.
Keywords: Insulin; SNEDDS; Hypoglycemia; Pharmacokinetic; Oral drug delivery; Enteric coating;

Soluplus® based 9-nitrocamptothecin solid dispersion for peroral administration: Preparation, characterization, in vitro and in vivo evaluation by Xianghong Lian; Jianxia Dong; Jinjie Zhang; Yanwei Teng; Qing Lin; Yao Fu; Tao Gong (399-407).
Display OmittedOur study aimed to develop an amorphous 9-nitrocamptothecin solid dispersion (9-NC-SD) using polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus®) for improving its oral bioavailability and antitumor efficacy in vivo. Freeze-dried 9-NC-SD with an optimized drug/polymer ratio at 1:15 (w/w) was characterized by powder X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The amorphous form of 9-NC was obtained by freeze-drying and the aqueous solubility of 9-NC was increased to 1.42 mg/mL. Upon dilution, 9-NC-SD was proven to form micellar structures with an average size distribution around 58 nm ± 5 nm (PDI = 0.107 ± 0.016). Moreover, 9-NC-SD showed significantly increased intracellular uptake efficiency in Caco-2 cells compared to free 9-NC. Furthermore, the AUC0–8 h of 9-NC-SD following oral administration showed a 2.68-fold increase in the lactone form of 9-NC compared to that of free 9-NC in Sprague-Dawley rats. The 9-NC-SD did not show obvious inflammatory responses and gastrointestinal toxicity following oral administration as demonstrated by the histological analysis of the rat intestinal sections. Thus, 9-NC-SD represents a promising approach for improving the solubility and oral bioavailability of drugs with poor solubility.
Keywords: 9-Nitrocamptothecin; Soluplus®; Solid dispersion; Oral bioavailability; Antitumor effect;

The enhanced longevity and liver targetability of Paclitaxel by hybrid liposomes encapsulating Paclitaxel-conjugated gold nanoparticles by Quan-Ying Bao; Ning Zhang; Dong-Dong Geng; Jing-Wei Xue; Mackenzie Merritt; Can Zhang; Ya Ding (408-415).
Liposomes and gold nanoparticles act as the model systems of organic and inorganic drug delivery systems, respectively, to construct a hybrid carrier for maintaining the superiority of both vehicles and improves the performance of Paclitaxel in the hybrid system. These hybrid liposomes provide a promising potential to further construct a compound preparation with improved performance based on their enhanced longevity and liver targetability of Paclitaxel.Display OmittedOrganic and inorganic drug delivery systems both demonstrate their own advantages and challenges in practical applications. Combining these two drug delivery strategies in one system is expected to solve their current issues and achieve desirable functions. In this paper, gold nanoparticles (GNPs) and liposomes have been chosen as the model systems to construct a hybrid system and investigate its performance for the tumor therapy of Paclitaxel (PTX). The thiol-terminated polyethylene glycol (PEG400)–PTX derivative has been covalently modified on the surface of GNPs, followed by the encapsulation of PTX-conjugated GNPs (PTX–PEG400@GNPs) in liposomes. The hybrid liposomes solve the solubility and stability problems of gold conjugates and show high drug loading capacity. In vitro PTX release from the hybrid system maintains the similar sustained behavior demonstrated in its conjugates. Under the protection of a biocompatible liposome shell, encapsulated PTX shows enhanced circulation longevity and liver targetability compared to Taxol® and PTX–PEG400@GNPs suspension in the pharmacokinetic and biodistribution studies. These indicate that encapsulating drug-conjugated inorganic nanoparticles inside organic carriers maintains the superiority of both vehicles and improves the performance of hybrid systems. Although these attributes of hybrid liposomes lead to a better therapeutic capacity in a murine liver cancer model than that of the comparison groups, it shows no significant difference from Taxol® and conjugate suspension. This result could be due to the delayed and sustained drug release from the system. However, it indicates the promising potential for these hybrid liposomes will allow further construction of a compound preparation with improved performance that is based on their enhanced longevity and liver targetability of Paclitaxel.
Keywords: Hybrid liposomes; Gold conjugates; Paclitaxel; Pharmacokinetics; Biodistribution; Anticancer efficacy;

Influence of lidocaine hydrochloride and penetration enhancers on the barrier function of human skin by Kazumasa Hirata; Diar Mohammed; Jonathan Hadgraft; Majella E. Lane (416-420).
Display OmittedSkin penetration enhancers (SPEs) are commonly employed in pharmaceutical and personal care products. These compounds transiently alter the barrier properties of the skin and we have previously investigated the effects of specific SPEs on skin barrier function in vivo. In the present study the effects of incorporation of an active pharmaceutical ingredient (API), lidocaine hydrochloride (LID HCl) in the SPEs previously studied were investigated. Solutions of LID HCl were prepared and applied to the volar forearm of human subjects with occlusion for 24 h. Subsequently, tape stripping and trans epidermal water loss (TEWL) measurements were conducted for treated and control sites. The activities of the desquamatory proteases, kallikrein 5 (KLK 5) and kallikrein 7 (KLK 7) and API content were also measured from the tape strips. The propylene glycol (PG) formulation increased TEWL significantly (p  < 0.05) compared with the other SPEs and a mixture of the SPEs. However, only the isopropyl myristate (IPM) solution altered protease activity with a significant observed increase in kallikrein 5 (KLK 5). Incorporation of LID HCl appeared to ameliorate the effects of some of the SPEs on TEWL measurements compared with our previous study. Overall uptake of LID HCl into skin from the various formulations correlated very well with changes in TEWL. The findings should have implications for the choice of SPEs in topical and transdermal formulations, particularly where the skin barrier function of patients is already impaired for example in atopic eczema or psoriasis.
Keywords: Skin penetration enhancers; Proteases; Trans epidermal water loss; Lidocaine hydrochloride;

Preparation and optimization of ophiopogon polysaccharide liposome and its activity on Kupffer cells by Yunpeng Fan; Xiaoping Song; Yuanyuan Gao; Ying Chen; Lin Ma; Weimin Zhang; Weifeng Hou; Chao Guo; Dewen Tong (421-430).
Display OmittedThe purpose of this study was to prepare and optimize ophiopogon polysaccharide liposome (OPL), and to improve the immune-enhancing activity of ophiopogon polysaccharide (OP). OPL was prepared and optimized using the methods of reverse-phase evaporation and response surface methodology. The property was evaluated with particle size, zeta potential, and morphology. The results showed that the optimum preparation conditions were: soybean phosphatide to OP ratio of 9.5:1, soybean phospholipid to cholesterol ratio of 8:1, and chloroform to phosphate-buffered saline ratio of 3:1. Subsequently, the immune-enhancing activity of OPL on Kupffer cells (KCs) was performed. The results showed that OPL could significantly promote the phagocytosis of KCs, induce the secretion of nitric oxide, induced nitric oxide synthase, IL-6 and IL-12, and improve the expression of CD80 and CD86 compared with OP at 125–7.813 μg mL−1. These results indicated that the immune-enhancing activity of OP was significantly improved after encapsulated with liposome. Therefore, liposome would be expected to exploit into a new-type preparation of OP.
Keywords: Ophiopogon polysaccharide liposome; Response surface methodology; Kupffer cells; Immune-enhancing activity;

Quality by Design approach to understand the physicochemical phenomena involved in controlled release of captopril SR matrix tablets by J. Saurí; D. Millán; J.M. Suñé-Negre; H. Colom; J.R. Ticó; M. Miñarro; P. Pérez-Lozano; E. García-Montoya (431-441).
Display OmittedThe aim of this study is to obtain swelling controlled release matrix tablets of captopril using the Quality by Design methodology (ICH Q8) and to know the transport mechanisms involved in captopril release. To obtain the area of knowledge, the design of experiments studying the effect of two components (HPMC K15M and ethylcellulose) at different levels has been applied, with the captopril dissolution profile as the product’s most important critical quality attribute (CQA). Different dissolution profiles have been obtained with the design of experiments performed, which is a key factor in the development of controlled release matrix tablets. Kinetic analysis according to the equations of Higuchi and Korsmeyer–Peppas demonstrates that the release mechanism is a mechanism of erosion when the whole percentage of the polymer is ethylcellulose, and a diffusion mechanism when the whole percentage of the polymer is HPMC K15M. The physico-chemical characteristics of the gel layer determine the release rate of captopril. The thickness of the gel layer, the porosity which is formed in the matrix upon contact with water, pore size, the swelling rate, the erosion rate of the matrix, and the physico-chemical characteristics of captopril, are factors related to the kinetic equations described and that allow us to predict the release mechanism of captopril. A new relationship of the kinetic equations governing the in vitro behavior with the physical characteristics of the gel layer of the different formulations has been established. This study shows that the size of water-filled pores and the degree of crosslinking between the chains of HPMC K15M of the matrix are related to the exponent n of the Korsmeyer–Peppas equation and the type of transport of the captopril from within the matrix to the dissolution medium, that is, if the transport is only through water-filled pores, or if a combination of diffusion occurs through water-filled pores with a transport through continuous polymeric networks.
Keywords: Quality by Design; Matrix tablets; Swelling controlled release; Image analysis; Drug release mechanism; Front movements;

Synthesis, biological activity, and biopharmaceutical characterization of tacrine dimers as acetylcholinesterase inhibitors by Shuai Qian; Lisi He; Marvin Mak; Yifan Han; Chun-Yu Ho; Zhong Zuo (442-453).
Display OmittedTacrine (THA), as the first approved acetylcholinesterase (AChE) inhibitors for the treatment of Alzheimer’s disease (AD), has been extensively investigated in last seven decades. After dimerization of THA via a 7-carbon alkyl spacer, bis(7)-tacrine (B7T) showed much potent anti-AChE activity than THA. We here report synthesis, biological evaluation and biopharmaceutical characterization of six THA dimers referable to B7T. According to IC50 values, the in vitro anti-AChE activities of THA dimers were up to 300-fold more potent and 200-fold more selective than that of THA. In addition, the anti-AChE activities of THA dimers were found to be associated with the type and length of the linkage. All studied THA dimers showed much lower cytotoxicity than B7T, but like B7T, they demonstrated much lower absorptive permeabilities than that of THA on Caco-2 monolayer model. In addition, all THA dimers demonstrated significant efflux transport (efflux ratio >4), indicating that the limited permeability could be associated with the efflux transport during absorption process. Moreover, the dimer with higher Log P value was accompanied with higher permeability but lower aqueous solubility. A balanced consideration of activity, solubility, cytotoxicity and permeability should be conducted in selection of the potential candidates for further in vivo investigation.
Keywords: Tacrine; Dimers; Acetylcholinesterase; Cytotoxicity; Permeability;

Sterically stabilized polymeric nanoparticles with a combinatorial approach for multi drug resistant cancer: In vitro and in vivo investigations by Sobiya Zafar; Lalit Mohan Negi; Anita Kamra Verma; Vijay Kumar; Aakriti Tyagi; Pratibha Singh; Zeenat Iqbal; Sushama Talegaonkar (454-468).
Display OmittedThe present work describes the preparation of sterically stabilize polymeric nanoparticles of mitoxantrone dihydrochloride (MTO) along with an efflux transporter (Pgp/BCRP) inhibitor that enhance the circulation time of nanoparticles and simultaneously surmount the problem of multidrug resistance (MDR). Mitoxantrone dihydrochloride being hydrophilic in nature had very low entrapment efficiency (%E.E.), thus in order to further enhance the lipophilicity and the %E.E., it was complexed with sodium deoxycholate (SDC) and this MTO-SDC-complex was used to formulate nanoparticles with/without Pgp/BCRP inhibitor by nanoprecipitation technique and was characterized for various in vitro and in vivo attributes. In vitro cell line studies were conducted on MCF7, A2780(p) and A2780(adr) cells. Furthermore, the targeting potential of hyaluronic acid (HA) coated nanoparticles for CD44 receptors was investigated using the MCF7 cell line. A reduction in the IC50 value observed with the inhibitor loaded nanoparticles in different cell lines indicated the BCRP/Pgp inhibiting ability of the formulated nanoparticles. The reduced macrophage uptake and the increased residence time in blood demonstrated the long circulating behaviour of the nanoparticles. The enhanced cellular uptake of HA coated nanoparticles in MCF7 cells revealed their targeting potential. The HA coated nanoparticles along with efflux transporter inhibitor exhibits a great potential for targeted chemotherapy in CD44 overexpressing MDR breast cancer.
Keywords: CD44; Hyaluronic acid; Long circulating; Multidrug resistance; Nanoparticles;

Display Omitted In vitro estimation of release kinetics from drug delivery systems is needed in formulation development. Cost-effective methods of assessment for delivery systems are needed particularly in the case of biologicals and drug administration routes that are difficult to screen in vivo (e.g. intraocular drug delivery). As a proof-of-concept, we demonstrate here a practical high-throughput methodology to investigate in vitro drug release and predict resulting drug concentrations in the eye after intravitreal administration. 96-well plate based assay aided with robotic sampling was used to study release of eight model drugs of varying physicochemical properties (dexamethasone, vancomycin, alpha-lactalbumin, lysozyme, myoglobin, albumin, lactoferrin, human IgG) from twelve alginate microsphere formulations. The amount of drug released over a period of time was assessed by photometric and fluorescence methods. In vitro drug release rates obtained were used in pharmacokinetic simulations using one-compartment model of the vitreal cavity with anatomical volume of distribution and clearance estimates based on the literature precedence. An integrated approach of drug release screening and pharmacokinetic simulations can prove to be a useful methodology in guiding formulation development for ocular delivery in animal models. In general, the methodology has the potential to be a cost-effective tool for early stage drug delivery system discovery and development.
Keywords: High-throughput; Alginate microspheres; Ophthalmic drug delivery; Drug release; Pharmacokinetics;

Display OmittedAlthough, adhesion at the interface of bilayer tablets is critical for their design it is difficult to characterize this adhesion between layers. In view of this, a new test with an easy implementation was proposed for the characterization of the interface of bilayer tablets. This work is presented as a proof-of-concept study to investigate the reliability of this new test with regard to the effects of some critical process parameters (e.g., compaction pressure applied on each layer) and material attributes (e.g., elasticity of the layered materials) on the interfacial adhesion of bilayer tablets. This was investigated using a design of experiment approach and the results obtained were in good accordance with those obtained with other tests and thus, confirms the potential of such a method for the measurement of the interfacial adhesion of bilayer tablets.
Keywords: Bilayer tablet; Interfacial strength; Delamination; Elasticity; Test device;

Sodium colistimethate loaded lipid nanocarriers for the treatment of Pseudomonas aeruginosa infections associated with cystic fibrosis by Marta Pastor; María Moreno-Sastre; Amaia Esquisabel; Eulàlia Sans; Miguel Viñas; Daniel Bachiller; Víctor José Asensio; Ángel Del Pozo; Eusebio Gainza; José Luis Pedraz (485-494).
Display OmittedLung impairment is the most life-threatening factor for cystic fibrosis patients. Indeed, Pseudomonas aeruginosa is the main pathogen in the pulmonary infection of these patients. In this work, we developed sodium colistimethate loaded lipid nanoparticles, namely, solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), as a strategy to enhance the antimicrobial therapy against P. aeruginosa in cystic fibrosis patients. The nanoparticles obtained displayed a 200–400 nm size, high drug entrapment (79–94%) and a sustained drug release profile. Moreover, both SLN and NLC presented antimicrobial activity against clinically isolated P. aeruginosa. The integrity of the nanoparticles was not affected by nebulization through a mesh vibrating nebulizer. Moreover, lipid nanoparticles appeared to be less toxic than free sodium colistimethate in cell culture. Finally, an in vivo distribution experiment showed that nanoparticles spread homogenously through the lung and there was no migration of lipid nanoparticles to other organs, such as liver, spleen or kidneys.
Keywords: Sodium colistimethate; Lipid nanoparticles; NLC; Pseudomonas aeruginosa; Cystic fibrosis; Nanomedicine;

Bioadhesive emulsions for control release of progesterone resistant to vaginal fluids clearance by Maria Campaña-Seoane; Aaron Peleteiro; Reyes Laguna; Francisco J. Otero-Espinar (495-505).
Display OmittedThe aim of this study is to propose that mucoadhesive vaginal emulsions can be able to resist the clearance effect of vaginal fluid and to have an effective control release of progesterone. With this goal, silicon derivative, cyclomethicone pentamer, was selected as the bioadhesive and water resistant material. In order to obtain a system which is insensitive to the dilution of aqueous fluids, water in silicone (W/S) emulsions were prepared and different proportions of cyclomethicone as well as 8% or 15% w/w of progesterone were employed. The rheological, mechanical and mucoadhesive properties of emulsions were characterized and the drug release was measured for each formulation. Mucoadhesive behavior was determined and the influence of simulated vaginal fluid (SVF) at bioadhesion was assessed using three commercial mucoadhesive vaginal gels (Crinone®, K-Y jelly® and Zidoval®) as the bioadhesive references. All assayed emulsions have good rheological and mechanical properties and their consistence and viscosity increase when the proportion of the internal phase increases. Related to mucoadhesion, in the absence of SVF, W/S emulsions showed similar bioadhesive levels like the commercial formulations. However, in the presence of SVF, W/S emulsions are able to keep their mucoadhesive properties while the marketed references drastically lose their consistency and adherence to the vaginal mucosa. Drug release profiles from W/S emulsion show that progesterone is released with pseudo-order zero kinetics and a constant release rate is maintained for at least two weeks. The results of the in vivo studies developed in rats show that after a single vaginal administration, bioadhesive W/S emulsions increase the uterine tissue progesterone levels in young and postmenopausal rats. Moreover in postmenopausal rats, they provide high uterine levels of progesterone compared to the bioadhesive-marketed gel used as a reference. Therefore, W/S emulsions have an interesting potential as bioadhesive vaginal delivery systems for drug administration.
Keywords: Bioadhesion; Vaginal delivery; Silicone emulsion; Progesterone;

Display OmittedThe aim of the current study is to explore the potential of PEG-30-dipolyhydroxystearate (Cithrol® DPHS) and Soluplus® as ingredients in novel semisolid self-nanoemulsifying drug delivery systems (SNEDDS). Semisolid SNEDDS consisting of Cithrol® DPHS, Capmul® MCM and Kolliphor® HS 15 were successfully prepared. The formulations were comprehensively characterized by photon correlation spectroscopy (PCS), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), electron spin resonance (ESR) and proton nuclear magnetic resonance (1H NMR). All formulations were semisolid at room temperature and melted at body temperature. The hydrodynamic diameter of the dispersions was less than 25 nm. The ratio Cithrol® DPHS:Capmul® MCM was found to be critical for the dispersibility and the stability of the formed nanoemulsion.
Keywords: Selfemulsifying; SNEDDS; PEG-30-dipolyhydroxystearate; Cithrol® DPHS; Kolliphor® HS 15; Capmul® MCM; Soluplus®; Tempolbenzoate; ESR;

A new topical formulation for psoriasis: Development of methotrexate-loaded nanostructured lipid carriers by Maria Filipa Pinto; Catarina Costa Moura; Cláudia Nunes; Marcela A. Segundo; Sofia A. Costa Lima; Salette Reis (519-526).
Display OmittedThe aim of the present work was to develop and assess the potential of nanostructured lipid carriers (NLCs) loaded with methotrexate as a new approach for topical therapy of psoriasis. Methotrexate-loaded NLCs were prepared via a modified hot homogenization combined with ultrasonication techniques using either polysorbate 60 (P60) or 80 (P80) as surfactants. The produced NLCs were within the nanosized range (274–298 nm) with relatively low polydispersity index (<0.25) and zeta potential values around −40 mV. NLCs demonstrated storage stability at 25 °C up to 28 days. The entrapment efficiency of methotrexate in NLC-P60 and -P80 was ∼65%. Cryo-SEM images showed the spherical shape of the empty and methotrexate-loaded NLCs. FT-IR confirmed methotrexate presence within the NLCs. The in vitro release of methotrexate from the NLCs followed a fast release pattern reaching ∼70% in 2 h. In vitro skin penetration study demonstrated that methotrexate-loaded NLCs-P60 had higher skin penetration when compared to free methotrexate, suggesting a significant role of drug-nanocarriers on topical administration. Methotrexate-loaded NLC-P60 provided drug fluxes of 0.88 μg/cm2/h, higher (P  < 0.001) than with the free drug (control, 0.59 μg/cm2/h). The results indicate the potential of NLCs for the delivery of methotrexate to topical therapy of psoriasis.
Keywords: Methotrexate; Lipid nanoparticles; Skin permeation; Psoriasis; Transdermal drug delivery;

Chemical imaging and solid state analysis at compact surfaces using UV imaging by Jian X. Wu; Sönke Rehder; Frans van den Berg; José Manuel Amigo; Jens Michael Carstensen; Thomas Rades; Claudia S. Leopold; Jukka Rantanen (527-535).
Display OmittedFast non-destructive multi-wavelength UV imaging together with multivariate image analysis was utilized to visualize distribution of chemical components and their solid state form at compact surfaces. Amorphous and crystalline solid forms of the antidiabetic compound glibenclamide, and microcrystalline cellulose together with magnesium stearate as excipients were used as model materials in the compacts. The UV imaging based drug and excipient distribution was in good agreement with hyperspectral NIR imaging. The UV wavelength region can be utilized in distinguishing between glibenclamide and excipients in a non-invasive way, as well as mapping the glibenclamide solid state form. An exploratory data analysis supported the critical evaluation of the mapping results and the selection of model parameters for the chemical mapping. The present study demonstrated that the multi-wavelength UV imaging is a fast process analytical technique with the potential for real-time monitoring of critical quality attributes.
Keywords: UV imaging; NIR imaging; Multivariate image analysis; Multivariate curve resolution; Glibenclamide; Solid state packing;

Nanocarrier improves the bioavailability, stability and antitumor activity of camptothecin by Xin-Jiang Tang; Min Han; Bo Yang; You-Qing Shen; Zhong-Gui He; Dong-Hang Xu; Jian-Qing Gao (536-545).
Display OmittedCamptothecin (CPT) nanosuspension was prepared by anti-solvent precipitation with TPGS as stabilizer to improve the solubility, stability and antitumor activity of CPT. And an increased solubility, stability and dissolution rate was achieved after nanosuspension being prepared. While, enhanced intracellular accumulation and cellular cytotoxicity was also observed for CPT nanosuspension than that of CPT solution.In addition, nanosuspension could increase bioavailability and intratumor accumulation of CPT in vivo after intravenous administration, and then produced a much higher antitumor effect and biocompatibility than that of CPT solution. Meanwhile, an enhanced cellular CPT uptake in hypoxic or acid conditions could also be observed for nanosuspension. As a result, nanosuspension represents a potentially feasible formation for insoluble drug in antitumor research.
Keywords: Camptothecin; Nanosuspension; Antitumor effect; Side effect;

Pharmaceutical properties of a low-substituted hydroxypropyl cellulose (L-HPC) hydrogel as a novel external dressing by Atsushi Ogawa; Sachie Nakayama; Mami Uehara; Yasuhiro Mori; Mai Takahashi; Tetsuya Aiba; Yuji Kurosaki (546-552).
Display OmittedControlling the moisture balance between exudates and their transpiration from the surface of wounded skin is important for healing. Low-substituted hydroxypropyl cellulose (L-HPC) hydrogel sheets (HGSs) possessing high water retention and water vapor transmission properties were prepared by neutralizing the highly viscous alkaline liquid of 7–10% L-HPC. Glycerol-impregnated L-HPC hydrogel sheets (L-HPC G-HGSs) were obtained by exchanging aqueous liquid in L-HPC HGSs. The physical characteristics required for wound dressings, i.e., mechanical strength, adhesive strength, and water retention properties, as well as the water vapor transmission (WVT) properties of L-HPC HGSs and L-HPC G-HGSs were evaluated. The mechanical strengths of L-HPC HGSs were enhanced with increases in the L-HPC content. The impregnation of glycerol in L-HPC HGSs yielded a significantly elasticated sheet. The adhesive strengths of L-HPC HGSs were significantly lower than those of commercial medical dressings. Water retention in L-HPC HGSs after being stored for 2 h at 37 °C was approximately 50%. The WVT rate of 7% L-HPC HGS was approximately 40 g/m2/h, which was markedly higher than that of silicone gel type medical dressings. In conclusion, L-HPC HGSs are promising dressings that maintain an adequate moisture balance by transpiring excessive wound exudates with less damage to the healing wound.
Keywords: Hydrogel; Low-substituted hydroxypropyl cellulose (L-HPC); Dressing; Water retention; Water vapor transmission; Adhesive strength;

Bionanocomposites containing magnetic graphite as potential systems for drug delivery by Lígia N.M. Ribeiro; Ana C.S. Alcântara; Margarita Darder; Pilar Aranda; Paulo S.P. Herrmann; Fernando M. Araújo-Moreira; Mar García-Hernández; Eduardo Ruiz-Hitzky (553-563).
Display OmittedNew magnetic bio-hybrid matrices for potential application in drug delivery are developed from the assembly of the biopolymer alginate and magnetic graphite nanoparticles. Ibuprofen (IBU) intercalated in a Mg–Al layered double hydroxide (LDH) was chosen as a model drug delivery system (DDS) to be incorporated as third component of the magnetic bionanocomposite DDS. For comparative purposes DDS based on the incorporation of pure IBU in the magnetic bio-hybrid matrices were also studied. All the resulting magnetic bionanocomposites were processed as beads and films and characterized by different techniques with the aim to elucidate the role of the magnetic graphite on the systems, as well as that of the inorganic brucite-like layers in the drug-loaded LDH. In this way, the influence of both inorganic components on the mechanical properties, the water uptake ability, and the kinetics of the drug release from these magnetic systems were determined. In addition, the possibility of modulating the levels of IBU release by stimulating the bionanocomposites with an external magnetic field was also evaluated in in vitro assays.
Keywords: Bionanocomposites; Magnetic graphite; Layered double hydroxides; Drug delivery; Alginate; Ibuprofen; Controlled release;

Display OmittedThe present work aims to investigate applicability of antisolvent precipitation method for preparation of nanosized curcumin and to control their characteristics by determining the influence of process and solvents on solid-state properties of curcumin nanoparticles. Effects of different experimental parameters on particle size were investigated using dynamic light scattering. Particle morphology was studied using SEM. Drug content in stabilized nanoparticles was determined using HPLC. Residual moisture content after lyophilisation was determined using Karl Fischer method and solid state properties were investigated using DSC, TGA, FTIR and powder-XRD. The resulting product showed a high drug load and contained the drug in amorphous form. The particle diameters of prepared curcumin nanoparticles were found in the range of 100–200 nm. In vitro drug release studies indicated a sustained release profile of curcumin from the nanoparticles. Antisolvent precipitation produced amorphous curcumin nanoparticles whose size and morphology could be controlled using gelatine as stabilizer. Lyophilized curcumin nanoparticles with d-sorbitol as lyoprotectant possessed good redispersibility and showed up to 4 times faster in vitro curcumin release rate than that of unprocessed curcumin. Stability tests (at 2–8 °C and ambient conditions) indicated that the product was stable for up to 6 months of storage.
Keywords: Antisolvent; Curcumin; Nanoparticles; Non-solvent; Precipitation;

Administration strategies for proteins and peptides by D. Ibraheem; A. Elaissari; H. Fessi (578-589).
Display OmittedProteins are a vital constituent of the body as they perform many of its major physiological and biological processes. Recently, proteins and peptides have attracted much attention as potential treatments for various dangerous and traditionally incurable diseases such as cancer, AIDS, dwarfism and autoimmune disorders. Furthermore, proteins could be used for diagnostics. At present, most therapeutic proteins are administered via parenteral routes that have many drawbacks, for example, they are painful, expensive and may cause toxicity. Finding more effective, easier and safer alternative routes for administering proteins and peptides is the key to therapeutic and commercial success. In this context, much research has been focused on non-invasive routes such as nasal, pulmonary, oral, ocular, and rectal for administering proteins and peptides. Unfortunately, the widespread use of proteins and peptides as drugs is still faced by many obstacles such as low bioavailability, short half-life in the blood stream, in vivo instability and numerous other problems. In order to overcome these hurdled and improve protein/peptide drug efficacy, various strategies have been developed such as permeability enhancement, enzyme inhibition, protein structure modification and protection by encapsulation. This review provides a detailed description of all the previous points in order to highlight the importance and potential of proteins and peptides as drugs.
Keywords: Protein; Peptides; Administration routes; Bioavailability; Encapsulation; Immunotherapy;

Enhanced gene delivery efficiency of cationic liposomes coated with PEGylated hyaluronic acid for anti P-glycoprotein siRNA: A potential candidate for overcoming multi-drug resistance by Rui Ran; Yayuan Liu; Huile Gao; Qifang Kuang; Qianyu Zhang; Jie Tang; Kai Huang; Xiaoxiao Chen; Zhirong Zhang; Qin He (590-600).
PEGylated hyaluronic acid (PEG–HA) was synthesized and employed to coat the cationic liposome-siRNA complex through electrostatic interaction to form PEG–HA–NP. Due to a reversed surface charge, PEG–HA–NP could keep stable in fetal bovine serum (FBS). In vitro studies demonstrated that PEG–HA–NP had two cell internalization pathways and it had comparable P-glycoprotein downregulation efficacy with Lipofectamine RNAiMAX. In vivo experiments illustrated that PEG–HA–NP possessed the best tumor accumulation, cellular uptake, and P-glycoprotein downregulation capability in tumor bearing mice compared with naked NP and HA–NP after systemic administration. Overall, PEG–HA–NP proved itself an efficient siRNA carrier and the ability of downregulating P-glycoprotein made it a potential candidate to overcome multi-drug resistance.Display OmittedRNA interference is an effective method to achieve highly specific gene regulation. However, the commonly used cationic liposomes have poor biocompatibility, which may lead to systematic siRNA delivery of no avail. PEGylation is a good strategy in shielding the positive charge of cationic liposomes, but the enhanced serum stability is often in company with compromised cellular uptake and endosome escape. In this study, PEG was covalently linked to negatively charged hyaluronic acid and it was used to coat the liposome-siRNA nanoparticles. The resulting PEG–HA–NP complex had a diameter of 188.6 ± 10.8 nm and a dramatically declined zeta-potential from +34.9 ± 4.0 mV to −18.2 ± 2.2 mV. Owing to the reversed surface charge, PEG–HA–NP could remain stable in fetal bovine serum (FBS) to up to 24 h. In contrast with normal PEGylation, hyaluronic acid and PEG co-modified PEG–HA–NP provided comparable cellular uptake and P-glycoprotein downregulation efficacy in MCF-7/ADR cells compared with Lipofectamine RNAiMAX and naked NP regardless of its anionic charged surface. Because of its good biocompatibility in serum, PEG–HA–NP possessed the best tumor accumulation, cellular uptake and subsequently the strongest P-glycoprotein silencing capability in tumor bearing mice compared with naked NP and HA–NP after i.v. injection, with a 34% P-glycoprotein downregulation. Therefore, PEG–HA coated liposomal complex was demonstrated to be a promising siRNA delivery system in adjusting solid tumor P-glycoprotein expression, which may become a potential carrier in reversing MDR for breast cancer therapy.
Keywords: Cationic liposome; PEGylated hyaluronic acid; siRNA delivery; P-glycoprotein downregulation; Tumor targeting delivery;

Lipid based nanocarrier system for the potential oral delivery of decitabine: Formulation design, characterization, ex vivo, and in vivo assessment by Yub Raj Neupane; Manish Srivastava; Nafees Ahmad; Neeraj Kumar; Aseem Bhatnagar; Kanchan Kohli (601-612).
Display OmittedThe aim of this study was to design and fabricate nanostructured lipid carrier (NLC) for the potential oral delivery of decitabine (DCB). NLC was prepared by cold homogenization technique and optimized by the Box–Behnken experimental design. It was further characterized by particle size, zeta potential, transmission electron microscopy (TEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), in vitro release study, and stability study. Moreover, ex vivo and in vivo efficacy of the NLC was assessed by gut permeation study, γ scintigraphy imaging, and MTT assay. NLC was found to have particle size (116.64 ± 6.67 nm), zeta potential (−31.8 ± 0.96 mV) and sustained drug release (80.23 ± 4.67%) up to 24 h. TEM and AFM proved that the particles were spherical in shape and smooth surface. DSC and XRD studies had demonstrated the reduced crystallinity and stability enhancing effect of the NLC. Stability studies revealed the changes in the observed parameters up to 45 days were not significantly differences (p  > 0.05). Ex vivo gut permeation study showed 4-folds increment in the permeation of drug compared with the plain drug solution. γ Scintigraphy imaging and MTT assay results inferred that DCB loaded NLC possesses excellent cytotoxic activity against cancer cells. Thus, NLC holds high potential for the oral delivery of DCB to treat cancer cells and future prospects for the industrial purpose.
Keywords: Atomic force microscopy; Decitabine; γ Scintigraphy; Lipid based nanocarrier; Oral drug delivery;

PEGylated mesoporous silica as a redox-responsive drug delivery system for loading thiol-containing drugs by Qinfu Zhao; Chen Wang; Ying Liu; Jiahong Wang; Yikun Gao; Xiaojing Zhang; Tongying Jiang; Siling Wang (613-622).
Display OmittedIn this paper, we describe the development of a redox-responsive delivery system based on 6-mercaptopurine (6-MP)-conjugated colloidal mesoporous silica (CMS) via disulfide bonds. mPEG was modified on the surface of silica to improve the dispersibility and biocompatiblity of CMS by reducing hemolysis and protein adsorption. The CMS carriers with different amounts of thiol groups were prepared to evaluate the impact of modified thiol on the drug loading efficiency. In vitro release studies demonstrated that the CMS nanoparticles exhibited highly redox-responsive drug release. The cumulative release of 6-MP was less than 3% in absence of GSH, and reached more than 70% within 2 h in the presence of 3 mM GSH. In addition, by comparing the cumulative release profiles of CMS-SS-MP@mPEG with their counterparts without the grafting of hydrophilic PEG, it was found that mPEG chains did not hinder the drug release due to the cleavable disulfide bonds and the improved dispersibility. Overall, this work provides a new strategy to connect thiol-containing/thiolated drugs and hydrophilic polymers to the interior and exterior of silica via disulfide bonds to obtain redox-responsive release and improve the dispersibility and biocompatibility of silica.
Keywords: Colloidal mesoporous silica; Redox-responsive; 6-Mercaptopurine; Methoxy polyethylene glycols; Disulfide bonds;

Defining cisplatin incorporation properties in thermosensitive injectable biodegradable hydrogel for sustained delivery and enhanced cytotoxicity by Hend Mohamed Abdel-Bar; Amal Youssef Abdel-Reheem; Rihab Osman; Gehanne A.S. Awad; Nahed Mortada (623-630).
Display OmittedInjectable thermoreversible chitosan (CS)/β-glycerophosphate (β-GP) hydrogels were developed for prolonged localized delivery of cisplatin (Cis). The effects of formulation variables on the thermoreversible hydrogels preparation as well as the impact of drug incorporation method on Cis release were studied. Antitumor activity of Cis CS/β-GP thermoreversible hydrogels were evaluated against HCT-116 human colorectal cancer cells and MCF-7 human breast cancer cells. Incorporation of Cis to CS solution adjusted at pH 6.2 prior to hydrogel preparation deemed necessary to achieve a sustained release up to 4 days. Cis loaded CS/β-GP thermoreversible hydrogels showed enhanced antitumor activity with about 1.2 fold and 2.05 fold that of Cis solution against HCT-116 cancer cells and MCF-7 cancer cells respectively. The obtained enhanced antitumor activity elected this delivery system for further in vivo and toxicological investigations.
Keywords: Cisplatin; Chitosan; β-glycerophosphate; Thermoreversible hydrogels; Controlled drug incorporation;

Display OmittedNaltrexone hydrochloride (NTX) is an innovative drug used in ophthalmology for treatment of ocular surface diseases such as impaired corneal wound healing and severe dry eye. Poor chemical stability has been a major limitation for development of NTX in solution form. The aim of this study was to develop and characterise NTX in situ ocular films for enhanced chemical stability and improved ocular tolerability. The films were prepared from different amorphous polymers and characterised for physicochemical compatibility, moisture-sorption, surface pH, mechanical properties, sterilisability, surface morphology, mucoadhesion, in vitro release, conjunctival irritation and accelerated stability at 40 °C/75% relative humidity for 3 months. Glycerin (GLY)-plasticised films exhibited significantly better mechanical properties, compared with polyethylene glycol (PEG) 400 and triethylcitrate (TEC)-plasticised formulations. Superior mucoadhesion was recorded for F7 and F9 plasticised with GLY and PEG 400, respectively. The stability of NTX was significantly enhanced more than 18-times, compared with the solution form. Combination of carboxymethylcellulose sodium (CMC) and sodium alginate (ALG) in a film formulation demonstrated minimal % moisture sorption, good mechanical properties, in vitro release, excellent chemical stability and minimal conjunctival irritation lending them as promising ocular formulations.
Keywords: Naltrexone hydrochloride; In situ gel ocular films; Polymers; Plasticisers; Corneal wound healing;

Display OmittedPreformulation study of rotary spun hydroxypropyl cellulose fibers was carried out using the combination of textural characterization of gels in the concentration range of 42–60% w/w and optical microscopic evaluation of formed fibers. High adhesiveness values resulted in bead formation at lower polymer concentration, meanwhile fiber formation was hindered when high adhesiveness values were associated with high polymer content. The optimum gel concentration for fiber formation was given to 50% w/w.Drug loaded microfibers were prepared using a model drug of biopharmaceutical drug classification system class II. Fibers were milled, sieved and mixed with tableting excipients in order to directly compress orodispersible tablets. Hardness, friability, in vitro disintegration time values complied with the pharmacopoeial requirements. In vitro dissolution profiles obtained from three distinct dissolution media (pH 1.0; 4.5; 6.8) were quite differentiated compared to the compressed physical mixture of the same composition. Difference and similarity factors confirmed that the drug dissolution from microfiber based formula was almost independent from the pH value of the media. X-ray diffraction patterns indicated that the drug embedded in microfibers was in amorphous state, and the decrease of o-Ps lifetime values suggested that fiber formation enabled the development of a more ordered fibrous system.
Keywords: High-speed rotary spinning; Microfibers; Hydroxypropyl cellulose; Orodispersible tablet; Dissolution enhancement;

Transbuccal delivery of doxepin: Studies on permeation and histological investigation by Alvaro Gimeno; Ana C. Calpena; Roser Sanz; Mireia Mallandrich; Concepción Peraire; Beatriz Clares (650-654).
Display OmittedAccording to previous studies reporting the anesthetic/analgesic action of oral topical doxepin administration, this study evaluated a model of buccal permeation to determine the depth of delivery of doxepin into excised porcine buccal mucosa following topical application of a saturated aqueous doxepin solution. Buccal mucosa permeation studies were performed using Franz diffusion cells. Cumulative amounts of doxepin permeated were plotted as a function of time. Kinetic permeation parameters as flux (J s), lag time (T l) and permeability coefficient (K p) were calculated. Theoretical human plasmatic steady-state doxepin concentration and drug retained in the tissue were also determined in order to evaluate its potential therapeutic use, central or peripheral. Finally, a histological evaluation of the buccal mucosa was performed to test potential damage due to the permeation phenomenon. Obtained results showed a poor aqueous doxepin permeation through buccal mucosa membrane (median parameters J s  = 34.79 μg/h, K p  = 0.49 × 10−3  cm/h and T l  = 2.8 h). Predicted doxepin plasma concentrations would reach 46 ng/mL, far from the required to have central nervous system activity as tricyclic agent. However, median doxepin amount remaining in the mucosa membrane was 0.24 μg/cm2/μg tissue, which evidenced a reservoir function of the buccal mucosa. Histologically, no structural damage was observed in the tissues. This study lays the foundation for further research within this area with a view to potentially adopting alternative strategies for enhanced buccal absorption of doxepin in clinical practice.
Keywords: Doxepin; Buccal delivery; Pain; Porcine buccal mucosa; Ex vivo drug permeation;