International Journal of Pharmaceutics (v.485, #1-2)
EDITORIAL BOARD (iii).
Can preschool-aged children swallow several minitablets at a time? Results from a clinical pilot study by A. Kluk; M. Sznitowska; A. Brandt; K. Sznurkowska; K. Plata-Nazar; M. Mysliwiec; B. Kaminska; H. Kotlowska (1-6).
Display OmittedMinitablets are a novel, multi-compartment solid drug formulation, particularly intended for children between 1 and 6 years of age. Available literature shows that even infants are capable of swallowing a single minitablet. In this study, we have explored the level of acceptance of minitablets administered in units of 5 or 10.A group of thirty two 2-year-old children (2-years) and twenty eight 3-year-old children (3-years) have been enrolled in the study. Each child was asked to swallow placebo minitablets (2 mm or 3 mm) suspended in a fruity jelly on a spoon.The swallowing of minitablets (with or without chewing) was registered for 75% of 2-year-olds and for 93% of 3-year-olds. Moreover, most of the children (57% of all participants) were fully capable of swallowing all units without chewing (2-years: 50%; 3-years: 64%). However, no statistically significant differences in the swallowing ability were observed in gender and age groups. None of the children choked. Neither the number, nor the diameter of the administered minitablets have significantly influenced the ability to swallow units.The results show that minitablets administered in several units mixed with jelly food are safe and could be accepted by a pediatric population.
Keywords: Minitablets; Swallowing; Children;
Synthesis and characterization of silk fibroin microparticles for intra-articular drug delivery by Timothy K. Mwangi; Robby D. Bowles; David M. Tainter; Richard D. Bell; David L. Kaplan; Lori A. Setton (7-14).
Display OmittedTo determine the utility of silk fibroin (SF) microparticles as sustained release vehicles for intra-articular delivery.SF formulations were varied to generate microparticle drug carriers that were characterized in vitro for their physical properties, release kinetics for a conjugated fluorophore (Cy7), and in vivo for intra-articular retention time using live-animal, fluorescence in vivo imaging.SF microparticle carriers were spherical in shape and ranged from 598 nm to 21.5 μm in diameter. SF microparticles provided for sustained release of Cy7 in vitro, with only 10% of the initial load released over 7 days. Upon intra-articular injection in rat knee joints, the SF microparticles were associated with an intra-articular fluorescence decay half-life of 43.3 h, greatly increasing the joint residence over that for an equivalent concentration of SF-Cy7 in solution form. The SF microparticles also increase the localization of dye within the joint cavity as determined by image analysis of fluorescent gradients, significantly reducing distribution of the Cy7 to neighboring tissue as compared to SF-Cy7 in free solution.Silk microparticles act to provide for localized and sustained delivery of loaded small molecules following intra-articular injection, and may be an attractive strategy for delivering small molecule drugs for the treatment of arthritis.
Keywords: Intra-articular; Drug delivery; Silk fibroin; Microparticles; In vivo imaging; Osteoarthritis;
Cryopreservation of microencapsulated murine mesenchymal stem cells genetically engineered to secrete erythropoietin by Haritz Gurruchaga; Jesús Ciriza; Laura Saenz del Burgo; Juan Roberto Rodriguez-Madoz; Edorta Santos; Felipe Prosper; Rosa María Hernández; Gorka Orive; Jose Luis Pedraz (15-24).
Display OmittedThe ability to cryopreserve and store for long term the structure and function of therapeutic cells and tissues plays a pivotal role in clinical medicine. In fact, it is an essential pre-requisite for the commercial and clinical application of stem cells since preserves cells at low temperature and creates a reserve for future uses. This requisite may also affect the encapsulated stem cells. Several parameters should be considered on encapsulated cell cryopreservation such as the time and temperature during the cryopreservation process, or the cryoprotectant solutions used. In this study, we have compared the influence of penetrating and nonpenetrating cryoprotectants on the viability and functionality of encapsulated mesenchymal stem cells genetically modified to secrete erythropoeitin. Several cryoprotectant solutions combining DMSO, glycerol and trehalose at different concentrations were studied. Although almost no differences among the studied cryoprotectant solutions were observed on the differentiation potential of encapsulated mesenchymal stem cells, the penetrating cryoprotectant DMSO at a concentration of 10% displayed the best viability and erythropoietin secretion profile compared to the other cryoprotectant solutions. These results were confirmed after subcutaneous implantation of thawed encapsulated mesenchymal stem cells secreting erythropoeitin on Balb/c mice. The hematocrit levels of these animals increased to similar levels of those detected on animals transplanted with noncryopreserved encapsulated cells. Therefore, DMSO 10% represents the most suitable cryoprotectant solution among the solutions here studied, for encapsulated mesenchymal stem cells cryopreservation and its translation into the clinic. Similar studies should be performed for the encapsulation of other cell types before they can be translated into the clinic.
Keywords: Mesenchymal stem cells; Microencapsulation; Cryopreservation; Nanotechnology;
A geometric pore adsorption model for predicting the drug loading capacity of insoluble drugs in mesoporous carbon by Yikun Gao; Wenquan Zhu; Jia Liu; Donghua Di; Di Chang; Tongying Jiang; Siling Wang (25-30).
Display OmittedIn this work, a simple and accurate geometric pore-adsorption model was established and experimentally validated for predicting the drug loading capacity in mesoporous carbon. The model was designed according to the shape of pore channels of mesoporous carbon and the arrangement of drug molecules loaded in the pores. Three different small molecule drugs (celecoxib, fenofibrate and carvedilol) were respectively loaded in mesoporous carbon with different pore sizes. In order to test the accuracy of the established model, nitrogen adsorption–desorption analysis was employed to confirm the pore structure of mesoporous carbon and to calculate the occupation volume of the adsorbed drugs. The adsorption isotherms of celecoxib were systematically investigated to describe the adsorption process. It was found that the experimental results of adsorption capacity were all in the range of the predicted values for all the tested drugs and mesoporous carbon. The occupation volumes calculated from the model also agreed well with the experimental data. These results demonstrated that the established model could accurately provide the range of drug loading capacity, which may provide a useful option for the prediction of the drug loading capacity of small molecule drugs in mesoporous materials.
Keywords: Pore-adsorption model; Drug loading; Pore structure; Mesoporous carbon;
Injectable nanoparticle-loaded hydrogel system for local delivery of sodium alendronate by Urszula Posadowska; Martin Parizek; Elena Filova; Malgorzata Wlodarczyk-Biegun; Marleen Kamperman; Lucie Bacakova; Elzbieta Pamula (31-40).
Display OmittedSystemic administration of bisphosphonates, e.g. sodium alendronate (Aln) is characterized by extremely low bioavailability and high toxicity. To omit aforementioned drawbacks an injectable system for the intra-bone delivery of Aln based on Aln-loaded nanoparticles (NPs-Aln) suspended in a hydrogel matrix (gellan gum, GG) was developed. Aln was encapsulated in poly(lactide-co-glycolide) (PLGA 85:15) by solid–oil–water emulsification. Drug release tests showed that within 25 days all the encapsulated drug was released from NPs-Aln and the release rate was highest at the beginning and decreased with time. In contrast, by suspending NPs-Aln in a GG matrix, the release rate was significantly lower and more constant in time. The GG–NPs-Aln system was engineered to be easily injectable and was able to reassemble its structure after extrusion as shown by rheological measurements. In vitro studies showed that the GG–NPs-Aln was cytocompatible with MG-63 osteoblast-like cells and it inhibited RANKL-mediated osteoclastic differentiation of RAW 264.7 cells. The injectability, the sustained local delivery of small doses of Aln and the biological activity render the GG–NPs-Aln system promising for the local treatment of osteoporosis and other bone tissue disorders.
Keywords: Sodium alendronate; Injectability; Gellan gum; PLGA; Nanoparticles; Osteoporosis;
The effect of shear and extensional viscosities on atomization of Newtonian and non-Newtonian fluids in ultrasonic inhaler by L. Broniarz-Press; T.R. Sosnowski; M. Matuszak; M. Ochowiak; K. Jabłczyńska (41-49).
Display OmittedThe paper contains results of the experimental study on atomization process of aqueous solutions of glycerol and aqueous solutions of glycerol–polyacrylamide (Rokrysol WF1) in an ultrasonic inhaler. In experiments the different concentration aqueous solutions of glycerol and glycerol–polyacrylamide have been tested. The results have been obtained by the use of laser diffraction technique. The differences between characteristics of ultrasonic atomization for test liquids have been observed. The analysis of drop size histograms shows that the different sizes of drops have been formed during atomization process. The present study confirmed the previous reports which suggested that the drops size changes with the increase in viscosity of solution changes in spray characteristics were also observed. It has been shown that the shear and extensional viscosities affect the process of atomization.
Keywords: Shear viscosity; Extensional viscosity; Atomization; Ultrasonic inhaler; Drop size histogram; Laser diffraction;
Single-walled carbon nanotubes functionalized with aptamer and piperazine–polyethylenimine derivative for targeted siRNA delivery into breast cancer cells by Marzieh Mohammadi; Zahra Salmasi; Maryam Hashemi; Fatemeh Mosaffa; Khalil Abnous; Mohammad Ramezani (50-60).
Display OmittedEpithelial cell adhesion molecule (EpCAM) is a glycosylated type 1 membrane protein which is frequently over expressed in most solid tumors and it has recently been identified as a cancer stem cell (CSC) marker. Specific targeting of CSCs using nano-carriers would enhance treatment efficacy of cancer. In this study, we used a RNA aptamer against EpCAM (EpDT3) attached physically to our newly synthesized non-viral vector, based on single-walled carbon nanotube (SWNT) conjugated to piperazine–polyethylenimine derivative. The DNA transfection efficiency and siRNA delivery activity of the synthesized vector was investigated against upregulated BCL9l, which has been associated with breast and colorectal cancers.The complexes of the vector–aptamer/siRNA could specifically induce apoptosis by more than 20% in MCF-7 cell line as a positive EpCAM than MDA-MB-231 cells which are EpCAM negative. The decrease of BCL9l protein level was observed with western blot analysis in MCF-7 cells indicating the targeted silencing activity of the complex.
Keywords: Gene delivery; Aptamer; Epithelial cell adhesion molecule; Single-walled carbon nanotube; siRNA;
Texture analysis as a tool to study the kinetics of wet agglomeration processes by Silvia Nalesso; Carlo Codemo; Erica Franceschinis; Nicola Realdon; Riccardo Artoni; Andrea C. Santomaso (61-69).
Display OmittedIn this work wet granulation experiments were carried out in a planetary mixer with the aim to develop a novel analytical tool based on surface texture analysis. The evolution of a simple formulation (300 g of microcrystalline cellulose with a solid binders pre-dispersed in water) was monitored from the very beginning up to the end point and information on the kinetics of granulation as well as on the effect of liquid binder amount were collected. Agreement between texture analysis and granules particle size distribution obtained by sieving analysis was always found. The method proved to be robust enough to easily monitor the process and its use for more refined analyses on the different rate processes occurring during granulation is also suggested.
Keywords: Wet granulation; Granulation kinetics; Planetary mixer; Texture analysis;
Quality by design approach for optimizing the formulation and physical properties of extemporaneously prepared orodispersible films by J. Carolina Visser; Willem M.C. Dohmen; Wouter L.J. Hinrichs; Jörg Breitkreutz; Henderik W. Frijlink; Herman J. Woerdenbag (70-76).
Display OmittedThe quality by design (QbD) approach was applied for optimizing the formulation of extemporaneously prepared orodispersible films (ODFs) using Design-Expert® Software. The starting formulation was based on earlier experiments and contained the film forming agents hypromellose and carbomer 974P and the plasticizer glycerol (Visser et al., 2015). Trometamol and disodium EDTA were added to stabilize the solution. To optimize this formulation a quality target product profile was established in which critical quality attributes (CQAs) such as mechanical properties and disintegration time were defined and quantified. As critical process parameters (CPP) that were evaluated for their effect on the CQAs the percentage of hypromellose and the percentage of glycerol as well as the drying time were chosen. Response surface methodology (RMS) was used to evaluate the effects of the CPPs on the CQAs of the final product. The main factor affecting tensile strength and Young’s modulus was the percentage of glycerol. Elongation at break was mainly influenced by the drying temperature. Disintegration time was found to be sensitive to the percentage of hypromellose. From the results a design space could be created. As long as the formulation and process variables remain within this design space, a product is obtained with desired characteristics and that meets all set quality requirements.
Keywords: Orodispersible films; Extemporaneous pharmacy preparations; Optimizing formulation; Quality by design; Quality target product profile; Critical quality attributes;
Solid formulations by a nanocrystal approach: Critical process parameters regarding scale-ability of nanocrystals for tableting applications by Annika Tuomela; Timo Laaksonen; Johanna Laru; Osmo Antikainen; Juha Kiesvaara; Jukka Ilkka; Olli Oksala; Seppo Rönkkö; Kristiina Järvinen; Jouni Hirvonen; Leena Peltonen (77-86).
Display OmittedNanocrystallization is among the foremost drug delivery platform approaches for the commercial development of poorly soluble drugs. There exists an urge to enable a universal shift of the production of the solid nanocrystal formulations from laboratory scale to industrially feasible scale. The success of any formulation development depends on its transferability to large scale manufacture. The objectives of the study were to increase the nanocrystallization batch size and to screen and optimize parameters for industrially feasible itraconazole (ITC) and indomethacin (IND) nanocrystal composition for tablet formulation. Thus, ITC and IND were transformed into nanocrystal suspensions, using an increased batch size of a wet milling process, freeze-dried, and further developed into both direct compression (DC) and granulated (G) tableting masses. According to the investigated powder and tablet properties (true density, flowability, dose uniformity, maximum upper punch force, crushing strength, dissolution and disintegration) and stability testings, it was clear that the amount of the nanocrystals in the solid tablet formulation is critical in order to fully utilize the benefits of the nanocrystals, i.e., fast dissolution, and to produce high-quality tablets. The DC designs of both the model drugs with compositions including 40% of freeze-dried nanocrystalline drug powder outperformed the corresponding granulated tablets in all parameters after the stability surveillance.
Keywords: Scale-up; Wet milling; Freeze-drying; Granulation; Tableting; Solid nanocrystal formulation;
Surface characterization and protein interaction of a series of model poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanocarriers for drug targeting by Sven Staufenbiel; Marian Merino; Wenzhong Li; Mao-Dong Huang; Stefan Baudis; Andreas Lendlein; Rainer H. Müller; Christian Wischke (87-96).
Display OmittedThe surface properties of intravenously injected nanoparticles determine the acquired blood protein adsorption pattern and subsequently the organ distribution and cellular recognition. A series of poly[acrylonitrile-co-(N-vinyl pyrrolidone)] (PANcoNVP) model nanoparticles (133–181 nm) was synthesized, in which the surface properties were altered by changing the molar content of NVP (0–33.8 mol%) as the more hydrophilic repeating unit. The extent of achieved surface property variation was comprehensively characterized. The residual sodium dodecyl sulfate (SDS) content from the synthesis was in the range 0.3–1.6 μg ml−1, potentially contributing to the surface properties. Surface hydrophobicity was determined by Rose Bengal dye adsorption, hydrophobic interaction chromatography (HIC) and aqueous two-phase partitioning (TPP). Particle charge was quantified by zeta potential (ZP) measurements including ZP–pH profiles. The interaction with proteins was analyzed by ZP measurements in serum and by adsorption studies with single proteins. Compared to hydrophobic polystyrene model nanoparticles, all PANcoNVP particles were very hydrophilic. Differences in surface hydrophobicity could be detected, which did not linearly correlate with the systematically altered bulk composition of the PANcoNVP nanoparticles. This proves the high importance of a thorough surface characterization applying a full spectrum of methods, complementing predictions solely based on bulk polymer composition.
Keywords: Polymer nanoparticles; Protein adsorption; Surface characterization; Poly[acrylonitrile-co-(N-vinyl pyrrolidone)]; Surface hydrophobicity; Targeting;
Evaluation of microwave oven heating for prediction of drug–excipient compatibilities and accelerated stability studies by Anne Marie V. Schou-Pedersen; Jesper Østergaard; Claus Cornett; Steen Honoré Hansen (97-107).
Display OmittedMicrowave ovens have been used extensively in organic synthesis in order to accelerate reaction rates. Here, a set up comprising a microwave oven combined with silicon carbide (SiC) plates for the controlled microwave heating of model formulations has been applied in order to investigate, if a microwave oven is applicable for accelerated drug stability testing. Chemical interactions were investigated in three selected model formulations of drug and excipients regarding the formation of ester and amide reaction products. In the accelerated stability studies, a design of experiments (DoE) approach was applied in order to be able to rank excipients regarding reactivity: Study A: cetirizine with PEG 400, sorbitol, glycerol and propylene glycol. Study B: 6-aminocaproic acid with citrate, acetate, tartrate and gluconate. Study C: atenolol with citric, tartaric, malic, glutaric, and sorbic acid. The model formulations were representative for oral solutions (co-solvents), parenteral solutions (buffer species) and solid dosage forms (organic acids applicable for solubility enhancement). The DoE studies showed overall that the same impurities were generated by microwave oven heating leading to temperatures between 150 °C and 180 °C as compared to accelerated stability studies performed at 40 °C and 80 °C using a conventional oven. Ranking of the reactivity of the excipients could be made in the DoE studies performed at 150–180 °C, which was representative for the ranking obtained after storage at 40 °C and 80 °C. It was possible to reduce the time needed for drug–excipient compatibility testing of the three model formulations from weeks to less than an hour in the three case studies. The microwave oven is therefore considered to be an interesting alternative to conventional thermal techniques for the investigation of drug–excipient interactions during preformulation.
Keywords: Design of experiments; Drug–excipient compatibility; Drug stability; Formulation development; Kinetics; Microwave heating;
Development, optimization and evaluation of long chain nanolipid carrier for hepatic delivery of silymarin through lymphatic transport pathway by Shilpa Chaudhary; Tarun Garg; R.S.R. Murthy; Goutam Rath; Amit K. Goyal (108-121).
Display OmittedIn the present study, nanostructured lipid carriers (NLCs) with three different lipid combinations (solid lipid:liquid lipid) were prepared through emulsification and ultrasonication using a Box–Behnken design. From the design, the best lipid combination was glyceryl monostearate and oleic acid, which gives particle of smaller size (223.73 ± 43.39 nm) with high drug entrapment efficiency (78.65 ± 2.2%). In vitro release studies show that 84.60 ± 5.66% of drug was released in 24 h. In vivo studies revealed that drug absorption occurs through lymphatic pathway as only 5.008 ± 0.011 μg/ml of peak plasma concentration was achieved in blood plasma in presence of chylomicron inhibitor. The peak plasma concentration (C max) for silymarin loaded NLC was found to be 25.565 ± 0.969 μg/ml as compared to silymarin suspension whose C max was found to be 14.050 ± 0.552 μg/ml, this confirms 2-fold increase in relative bioavailability. In vivo studies revealed that 19.268 ± 1.29 μg of drug reaches to liver in 2 h whereas negligible drug concentration reported in other organs. It was concluded that drug loaded NLCs was beneficial for targeting liver or other lymphatic disorders through lymphatic transport pathway. Finally, the main purpose of modifying lymphatic transport system was successfully achieved through NLCs.
Keywords: Nanolipid carrier; Lymphatic system; Box–Behnken design; Liver target; Chylomicron;
Microfluidic-controlled manufacture of liposomes for the solubilisation of a poorly water soluble drug by Elisabeth Kastner; Varun Verma; Deborah Lowry; Yvonne Perrie (122-130).
Display OmittedBesides their well-described use as delivery systems for water-soluble drugs, liposomes have the ability to act as a solubilizing agent for drugs with low aqueous solubility. However, a key limitation in exploiting liposome technology is the availability of scalable, low-cost production methods for the preparation of liposomes. Here we describe a new method, using microfluidics, to prepare liposomal solubilising systems which can incorporate low solubility drugs (in this case propofol). The setup, based on a chaotic advection micromixer, showed high drug loading (41 mol%) of propofol as well as the ability to manufacture vesicles with at prescribed sizes (between 50 and 450 nm) in a high-throughput setting. Our results demonstrate the ability of merging liposome manufacturing and drug encapsulation in a single process step, leading to an overall reduced process time. These studies emphasise the flexibility and ease of applying lab-on-a-chip microfluidics for the solubilisation of poorly water-soluble drugs.
Keywords: Liposomes; Microfluidics; Poorly soluble drugs; Bilayer loading; High throughput;
Intestinal behavior of the ester prodrug tenofovir DF in humans by Sophie Geboers; Steven Haenen; Raf Mols; Joachim Brouwers; Jan Tack; Pieter Annaert; Patrick Augustijns (131-137).
Display OmittedTenofovir-disoproxil-fumarate (TDF) is a double ester prodrug which enables intestinal uptake of tenofovir (TFV) after oral administration in humans. In this study, prodrug stability was monitored in situ in the human intestine and in vitro using biorelevant media. In fasted state human intestinal fluids, the prodrug was completely degraded within 90 min, resulting in the formation of the mono-ester intermediate and TFV; in fed state intestinal fluids, the degradation rate of TDF was slightly reduced and no TFV was formed. Intestinal fluid samples aspirated after administration of TDF confirmed extensive intraluminal degradation of TDF in fasted state conditions; a relatively fast absorption of TDF partly compensated for the degradation. Although food intake reduced intestinal degradation, the systemic exposure was not proportionally increased. The lower degradation in fed state conditions may be attributed to competing esterase substrates present in food, lower chemical degradation in the slightly more acidic environment and micellar entrapment, delaying exposure to the “degrading” intestinal environment. The results of this study demonstrate premature intestinal degradation of TDF and suggest that TFV may benefit from a more stable prodrug approach; however, fast absorption may compensate for fast degradation, indicating that prodrug selection should not be limited to stability assays.
Keywords: Tenofovir; Ester prodrug; Intestinal absorption behavior; Human intestinal fluids; Clinical trial;
Nano-formulation of rifampicin with enhanced bioavailability: Development, characterization and in-vivo safety by Harinder Singh; Sahil Jindal; Mandeep Singh; Gaurav Sharma; Indu Pal Kaur (138-151).
Display OmittedNovel lipidic nanocarrier system of RIF with high drug loading of 50%, enhanced bioavailability and prolonged release.RIF-SLNs can be translated to reduced dose, dosage frequency and reduced side effects.Rifampicin (RIF) was encapsulated into solid lipid nanoparticles (SLNs) to overcome its poor and unreliable oral bioavailability. Novel microemulsification method with high drug loading (50%) and entrapment efficiency (∼67%) was developed (Indian Patent Application 3356/DEL/2013). RIF-SLNs were characterized using TEM, AFM, DSC and XRD. Near neutral SLNs (zeta −3.5 ± 0.8), with average particle size of 130.0 ± 22.6 nm showed 70.12% release in phosphate buffer pH 6.8 in 9 days. Single oral dose (50 mg/kg) pharmacokinetic studies in Wistar rats indicated 8.14 times higher (in comparison to free RIF) plasma bioavailability with sustained levels for 5 days. Pharmacodynamic parameters viz. T MIC (120 h; time for which plasma levels were above MIC of 0.2 μg/ml), AUC0–∞/MIC (1868.9 h) and C max/MIC (75.6) for RIF-SLNs were greater than free RIF by 2.5, 8.2 and 6.6 times, respectively. Similar LD50 (1570 mg/kg) and absence (or reversal in satellite group) of adverse events in repeat dose (three doses; highest dose was up to 50 times the human therapeutic dose) toxicity studies confirmed safety of RIF-SLNs. Improved pharmacokinetic profile of RIF-SLNs can be translated to a reduced dose and dosage frequency of RIF, thus resulting in lower or no hepatotoxicity commonly associated with its use.
Keywords: Lipidic nanoparticles; Rifampicin; Acute toxicity; Repeat dose toxicity; Pharmacokinetics;
In vitro dissolution of proton-pump inhibitor products intended for paediatric and geriatric use in physiological bicarbonate buffer by Fang Liu; Honaz Shokrollahi (152-159).
Drug release from omeprazole enteric-coated products in pH 4.5 PBS (45 min), and subsequent pH 6.8 phosphate buffer (a) and mHanks buffer (b).Display OmittedProton-pump inhibitor (PPI) products based on enteric coated multiparticulates are design to meet the needs of patients who cannot swallow tablets such as children and older adults. Enteric coated PPI preparations exhibit delays in in vivo absorption and onset of antisecretory effects, which is not reflected by the rapid in vitro dissolution in compendial pH 6.8 phosphate buffer commonly used for assessment of these products. A more representative and physiological medium, pH 6.8 mHanks bicarbonate buffer, was used in this study to evaluate the in vitro dissolution of enteric coated multiparticulate-based PPI products. Commercially available omeprazole, lansoprazole and esomeprazole products were subject to dissolution tests using USP-II apparatus in pH 4.5 phosphate buffer saline for 45 min (acid stage) followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, all nine tested products displayed rapid and comparable dissolution profiles meeting the pharmacopeia requirements for delayed release preparations. In pH 6.8 mHanks buffer, drug release was delayed and failed the pharmacopeia requirements from most enteric coated preparations. Despite that the same enteric polymer, methacrylic acid–ethyl acrylate copolymer (1:1), was applied to all commercial multiparticulate-based products, marked differences were observed between dissolution profiles of these preparations. The use of pH 6.8 physiological bicarbonate (mHanks) buffer can serve as a useful tool to provide realistic and discriminative in vitro release assessment of enteric coated PPI preparations and to assist rational formulation development of these products.
Keywords: Pellets; Dysphagia; Modified release; Physiological buffers; Bicarbonate media; Biorelevant dissolution;
Multiple withdrawals from single-use vials: A study on sterility by Alba Ripoll Gallardo; Grazia Meneghetti; Luca Ragazzoni; Vesselina Kroumova; Daniela Ferrante; Pier Luigi Ingrassia; Paola Ruzza; Angela Dell’Era; Esther Boniolo; Gjergji Koraqe; Fabrizio Faggiano; Francesco Della Corte (160-163).
Display OmittedReutilization of single-use vials containing medical drugs is still under discussion. This practice has been adopted as a standard to avoid drug wastage, particularly in developing countries and in the aftermath of disasters. Some studies have assessed sterility of medications stored in single-use vials after utilization as multiple doses; however, most of these were limited to one single drug, included a low number of samples and did not consider an intermediate transfer step from the vial to a disposable syringe. The purpose of this study was to assess microbial contamination of samples withdrawn over three days from disposable syringes prepared from single-use vials.A prospective sterility study was conducted. A total of 600 initial samples were prepared from six-hundred 10 mL single-use vials of physiological solution into six-hundred 20 mL disposable syringes. Samples were prepared in three different standard operating rooms, on six different days and by the same operator, using basic sterile technique. All syringes were capped, placed together in a non-sterile steel container, covered with a clean drape and stored in the refrigerator at 4° C under non-sterile conditions. Using basic sterile technique, four samples were withdrawn daily and cultured from each syringe over the next 3 days. Microbial growth was examined on Sabouraud agar and chocolate agar culture media.A total of 7200 samples were collected and 14,400 cultures were performed. No evidence of microbial growth in any of the culture media plates was found.This study demonstrated that contents initially stored in single-use vials and subsequently transferred into disposable syringes in an operating room using sterile technique, maintain sterility after 4 withdrawals per day for a total of 3 days.
Keywords: Single-use vial; Drug packaging; Drug storage; Disposable equipment; Drug contamination; Syringes/microbiology;
Local sustained-release delivery systems of the antibiofilm agent thiazolidinedione-8 for prevention of catheter-associated urinary tract infections by Julia Shenderovich; Mark Feldman; David Kirmayer; Abed Al-Quntar; Doron Steinberg; Eran Lavy; Michael Friedman (164-170).
Display OmittedThiazolidinedione-8 (TZD-8) is an anti-quorum-sensing molecule that has the potential to effectively prevent catheter-associated urinary tract infections, a major healthcare challenge. Sustained-release drug-delivery systems can enhance drugs’ therapeutic potential, by maintaining their therapeutic level and reducing their side effects. Varnishes for sustained release of TZD-8 based on ethylcellulose or ammonio methacrylate copolymer type A (Eudragit® RL) were developed. The main factors affecting release rate were found to be film thickness and presence of a hydrophilic or swellable polymer in the matrix. The release mechanism of ethylcellulose-based systems matched the Higuchi model. Selected varnishes were retained on catheters for at least 8 days. Sustained-release delivery systems of TZD-8 were active against Candida albicans biofilms. The present study demonstrates promising results en route to developing applications for the prevention of catheter-associated infections.
Keywords: Thiazolidinedione-8; Quorum sensing; Catheter-associated infections; Varnish; Modeling; Sustained release;
Improvement of the antibacterial activity of daptomycin-loaded polymeric microparticles by Eudragit RL 100: An assessment by isothermal microcalorimetry by Inês Santos Ferreira; Ana Bettencourt; Bertrand Bétrisey; Lídia M.D. Gonçalves; Andrej Trampuz; António J. Almeida (171-182).
Display OmittedThe aim of the present study was to develop novel daptomycin-loaded acrylic microparticles with improved release profiles and antibacterial activity against two clinically relevant methicillin-susceptible and methicillin-resistant Staphylococcus aureus strains (MSSA and MRSA, respectively). Daptomycin was encapsulated into poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL 100 (EUD) microparticles by a double emulsion-solvent evaporation method. For comparison purposes similar formulations were prepared with vancomycin. Particle morphology, size distribution, encapsulation efficiency, surface charge, physicochemical properties, in vitro release and biocompatibility were assessed. Particles exhibited a micrometer size and a spherical morphology. The addition of EUD to the formulation caused a shift in the surface charge of the particles from negative zeta potential values (100% PMMA formulations) to strongly positive. It also improved daptomycin encapsulation efficiency and release, whereas vancomycin encapsulation and release were strongly hindered. Plain and antibiotic-loaded particles presented comparable biocompatibility profiles. The antibacterial activity of the particles was assessed by isothermal microcalorimetry against both MSSA and MRSA. Daptomycin-loaded PMMA-EUD particles presented the highest antibacterial activity against both strains. The addition of 30% EUD to the daptomycin-loaded PMMA particles caused a 40- and 20-fold decrease in the minimum inhibitory (MIC) and bactericidal concentration (MBC) values, respectively, when compared to the 100% PMMA formulations. On the other hand, vancomycin-loaded microparticles presented the highest antibacterial activity in PMMA particles. Unlike conventional methods, isothermal microcalorimetry proved to be a real-time, sensitive and accurate method for assessment of antibacterial activity of antibiotic-loaded polymeric microparticles. Finally, the addition of EUD to formulations proved to be a powerful strategy to improve daptomycin encapsulation efficiency and release, and consequently improving the microparticles activity against two relevant S. aureus strains.
Keywords: Microencapsulation; Controlled release; PMMA; Eudragit; Daptomycin; Vancomycin; Isothermal microcalorimetry;
Solid lipid nanoparticles loaded with lipoyl–memantine codrug: Preparation and characterization by Sara Laserra; Abdul Basit; Piera Sozio; Lisa Marinelli; Erika Fornasari; Ivana Cacciatore; Michele Ciulla; Hasan Türkez; Fatime Geyikoglu; Antonio Di Stefano (183-191).
Display OmittedSolid lipid nanoparticles (SLNs) are considered very attractive drug-delivery systems (DDS) able to enhance the efficacy of some therapeutic agents in several pathologies difficult to treat in a conventional way. Starting from these evidences, this study describes the preparation, physicochemical characterization, release, and in vitro cytotoxicity of stealth SLNs as innovative approach to improve solubility and absorption through the gastrointestinal tract of lipoyl–memantine (LA–MEM), a potential anti-Alzheimer codrug.Physico-chemical properties of LA–MEM loaded SLNs have been intensively investigated. Differential scanning calorimetry (DSC) was used to clarify the state and crystalline structure of the formulation. The results obtained from particles size analysis, polydispersity (PDI), and zeta potential measurements allowed the identification of the optimized formulation, which was characterized by a drug-lipid ratio 1:5, an average intensity diameter of 170 nm, a PDI of 0.072, a zeta potential of −33.8 mV, and an entrapment efficiency of 88%. Moreover, in vitro stability and release studies in both simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), and preliminary in vitro cytotoxicity studies revealed that LA–MEM loaded SLNs could represent potential candidate for an in vivo investigation as DDS for the brain since it resulted devoid of citotoxicity and able to release the free codrug.
Keywords: Alzheimer’s disease; Codrug; Memantine; Lipoic acid; Solid lipid nanoparticles;
Fine powder flow under humid environmental conditions from the perspective of surface energy by Vikram Karde; Chinmay Ghoroi (192-201).
Display OmittedThe influence of humidity on surface energetics and flow behavior of fine pharmaceutical powders was investigated. Amorphous and crystalline fine powders with hydrophilic (Corn starch and Avicel PH105) and hydrophobic (ibuprofen) nature were considered for this study. The surface energy was determined using surface energy analyzer and flow behavior was measured in terms of unconfined yield stress (UYS) using a shear tester. The study showed that unlike hydrophobic ibuprofen powder, surface energy and flow of hydrophilic excipient powders were affected by relative humidity (RH). The Lifshitz–van der Waals dispersive (γ LW) component of surface energy barely changed with varying RH for all pharmaceutical powders. For hydrophilic excipients, the specific component of surface energy (γ SP) was found to increase with increasing RH. Furthermore, for these excipients, flow deterioration at elevated RH was observed due to increased capillary bridge formation. Detailed analysis showed that γ SP component of surface energy can be an effective indicator for flow behavior of fine powders under varying humid conditions. The present study also brought out the existence of different regimes of probable interparticle forces which dictate the bulk flow behavior of fine hydrophilic powder under humid conditions.
Keywords: Pharmaceutical powders; Humidity; Moisture sorption; Powder flow; Surface energy; Interparticle force;
Development and validation of an in vitro release method for topical particulate delivery systems by Maja Lusina Kregar; Marjana Dürrigl; Andrea Rožman; Želimir Jelčić; Biserka Cetina-Čižmek; Jelena Filipović-Grčić (202-214).
Display OmittedThe aim of this study was to develop an in vitro release method for topical particulate delivery systems using the immersion cell in combination with paddle dissolution apparatus. Chitosan- and methacrylate-based microparticles with mupirocin were prepared and used as model topical delivery systems for method development. Diffusion of the drug occurred across a mixed cellulose ester membrane, which demonstrated low drug adsorption and low diffusional resistance. After an initial lag phase the amount of drug released became proportional to the square root of time. The method was discriminative toward differences in formulation, as well as toward differences in drug concentration inside the sample compartment. The method was further used to confirm sameness between batches of the same composition prepared by the same process. Variations in paddle rotation speed (25 rpm, 50 rpm, 100 rpm), paddle height (1 cm, 2.5 cm) and volume of release medium (100 ml, 200 ml) did not significantly alter the release rates. The method of analysis was validated according to ICH guidelines. Currently there are no compendial or standard methods and apparatuses for in vitro release testing of topical microparticles. The developed method can be a useful guide in formulation development of such delivery systems.
Keywords: In vitro release; Immersion cell; Microparticles; Topical delivery; Mupirocin;
Characterization of naproxen-loaded solid SMEDDSs prepared by spray drying: The effect of the polysaccharide carrier and naproxen concentration by Katja Čerpnjak; Alenka Zvonar; Franc Vrečer; Mirjana Gašperlin (215-228).
Display OmittedThe purpose of this study was to prepare solid SMEDDS (sSMEDDS) particles produced by spray-drying using maltodextrin (MD), hypromellose (HPMC), and a combination of the two as a solid carrier. Naproxen (NPX) as the model drug was dissolved (at 6% concentration) or partially suspended (at 18% concentration) in a liquid SMEDDS composed of Miglyol® 812, Peceol™, Gelucire® 44/14, and Solutol® HS 15. Among the sSMEDDSs tested, the MD-based sSMEDDSs (with a granular, smooth-surfaced, microspherical appearance) preserved the self-microemulsifying properties of liquid SMEDDSs and exhibited dissolution profiles similar to those of liquid SMEDDSs, irrespective of the concentration of NPX. In contrast, HPMC-based sSMEDDSs (irregular-shaped microparticles) exhibited slightly prolonged release times due to the polymeric nature of the carrier. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and Raman mapping analysis confirmed molecularly dissolved NPX (at 6% of drug loading), whereas at 18% NPX loading drug is partially molecularly dissolved and partially in the crystalline state.
Keywords: Microcapsules; SEM; DSC; XRPD; Raman mapping; Dissolution profile improvement;
Inter-subject variability in intestinal drug solubility by Sarit Cohen Rabbie; Talia Flanagan; Paul D. Martin; Abdul W. Basit (229-234).
Display OmittedVariability in oral drug absorption is a well-known phenomenon, but it is often overlooked for its potential effects in oral drug delivery. Understanding the mechanisms behind absorption variability is crucial to understanding and predicting drug pharmacokinetics. In this study, the solubility of furosemide and dipyridamole – drugs known to have highly variable oral bioavailabilities – was investigated in individual ileostomy fluids from 10 subjects with ulcerative colitis. For comparison, drug solubility was also determined in pooled upper gastrointestinal fluids from healthy human subjects and simulated intestinal fluids. Ileostomy fluid characterization revealed high variability in buffer capacity and to a lesser degree for pH. Drug solubility in ileostomy fluids showed high variability. Correlation analysis revealed that dipyridamole solubility in these fluids is pH-dependent, whereas furosemide solubility was highly correlated to buffer capacity and pH. The implications of these results might partly explain the high variability in bioavailability in vivo, assuming that most of the observed variability is due to the absorption, and not the elimination, process.
Keywords: Oral absorption; Solubility; Inter-subject variability; Humans; Gastrointestinal fluids;
Design and optimization of topical methotrexate loaded niosomes for enhanced management of psoriasis: Application of Box–Behnken design, in-vitro evaluation and in-vivo skin deposition study by Aly A. Abdelbary; Mohamed H.H. AbouGhaly (235-243).
Display OmittedPsoriasis, a skin disorder characterized by impaired epidermal differentiation, is regularly treated by systemic methotrexate (MTX), an effective cytotoxic drug but with numerous side effects. The aim of this work was to design topical MTX loaded niosomes for management of psoriasis to avoid systemic toxicity. To achieve this goal, MTX niosomes were prepared by thin film hydration technique. A Box-Behnken (BB) design, using Design-Expert® software, was employed to statistically optimize formulation variables. Three independent variables were evaluated: MTX concentration in hydration medium (X 1), total weight of niosomal components (X 2) and surfactant: cholesterol ratio (X 3). The encapsulation efficiency percent (Y 1: EE%) and particle size (Y 2: PS) were selected as dependent variables. The optimal formulation (F12) displayed spherical morphology under transmission electron microscopy (TEM), optimum particle size of 1375.00 nm and high EE% of 78.66%. In-vivo skin deposition study showed that the highest value of percentage drug deposited (22.45%) and AUC0–10 (1.15 mg. h/cm2) of MTX from niosomes were significantly greater than that of drug solution (13.87% and 0.49 mg .h/cm2, respectively). Moreover, in-vivo histopathological studies confirmed safety of topically applied niosomes. Concisely, the results showed that targeted MTX delivery might be achieved using topically applied niosomes for enhanced treatment of psoriasis.
Keywords: Methotrexate; Niosomes; Box-Behnken; In-vivo skin deposition; In-vivo histopathological study;
Cationic peptides as RNA compaction agents: A study on the polyA compaction activity of a linear alpha,epsilon-oligo-l-lysine by Giovanni N. Roviello; Domenica Musumeci; Valentina Roviello (244-248).
Display OmittedIn this work, we investigate the compaction activity of a sequential alpha,epsilon-peptide composed of l-lysines towards two RNA targets, in view of its possible pharmaceutical application in RNA-targeting and RNA delivery. The basic oligolysine, object of the present study, proved not only to be efficient in compacting the single-stranded polyA RNA, but also to strongly interact with the polyA·polyU complex, as evidenced by CD-binding and UV-melting experiments. In particular, the marked differences in the CD spectra of the RNA targets upon addition of the peptide, as well as the different UV melting behaviour for the polyA·polyU complex in the presence and absence of the peptide, sustain the hypothesis of a strong RNA compaction capacity of the alpha,epsilon-oligolysine. Finally, by using HPLC analysis, we found a good resistance of the peptide against the lytic action of human serum, an important requirement in view of in vitro/in vivo biological assays.
Keywords: Basic peptide; Alpha,epsilon-oligolysine; polyA; polyA·polyU;
Lecithin/TPGS-based spray-dried self-microemulsifying drug delivery systems: In vitro pulmonary deposition and cytotoxicity by Rania A.H. Ishak; Rihab Osman (249-260).
Display OmittedThe aim of the present work was to develop a new solid self-microemulsifying drug delivery system (SMEDDS) for the pulmonary delivery of the poorly water-soluble anti-cancer drug atorvastatin (AVT). Microemulsion (ME) was first developed using isopropyl myristate (IPM), a combination of 2 biocompatible surfactants: lecithin/d-α-tocopheryl polyethylene glycol succinate (TPGS) and ethanol as co-surfactant. Two types of lecithin with different phosphatidylcholine (PC) contents were compared. Phase diagram, physico-chemical characterization and stability studies were used to investigate ME region. Solid SMEDDS were then prepared by spray-drying the selected ME using a combination of carriers composed of sugars, leucine as dispersibility enhancer with or without polyethylene glycol (PEG) 6000. Yield, flow properties, particle size and in vitro pulmonary deposition were used to characterize the spray-dried powders. Reconstituted MEs were characterized in terms of morphology, particle size and size distribution. In vitro cytotoxicity study was undertaken on lung cancer cell line for the selected MEs and SD-SMEDDS formulae. Results showed that the most satisfactory MEs properties were obtained with 1:3 lecithin/TPGS, 1:1 lecithin/oil and 1:1 surfactant/co-surfactant ratios. A larger ME area was obtained with lecithin containing 100% PC compared to the less expensive lecithin containing 20% PC. By manipulating spray drying parameters, carrier composition and ratio of ME lipids to carrier, microparticles with more than 70% of respirable fraction could be prepared. The ME was efficiently recovered in simulated lung fluid even after removal of alcohol. The concurrent delivery of AVT with TPGS in solid SMEDDS greatly enhanced the cytotoxic activity on lung cancer cells.
Keywords: Atorvastatin; Spray drying; SMEDDS; Lecithin; TPGS; Pulmonary deposition; Cytotoxicity;
Anticancer siRNA cocktails as a novel tool to treat cancer cells. Part (A). Mechanisms of interaction by Maksim Ionov; Joanna Lazniewska; Volha Dzmitruk; Inessa Halets; Svetlana Loznikova; Darya Novopashina; Evgeny Apartsin; Olga Krasheninina; Alya Venyaminova; Katarzyna Milowska; Olga Nowacka; Rafael Gomez-Ramirez; Francisco Javier de la Mata; Jean-Pierre Majoral; Dzmitry Shcharbin; Maria Bryszewska (261-269).
Display OmittedThis paper examines a perspective on the use of newly engineered nanomaterials as effective and safe carriers of genes for the therapy of cancer. Three different groups of cationic dendrimers (PAMAM, phosphorus and carbosilane) were complexed with anticancer siRNA and their biophysical properties of the dendriplexes analyzed. The potential of the dendrimers as nanocarriers for anticancer siBcl-xl, siBcl-2, siMcl-1 siRNAs and a siScrambled sequence was explored. Dendrimer/siRNA complexes were characterized by methods including fluorescence, zeta potential, dynamic light scattering, circular dichroism, gel electrophoresis and transmission electron microscopy. Some of the experiments were done with heparin to check if siRNA can be easily disassociated from the complexes, and whether released siRNA maintains its structure after interaction with the dendrimer. The results indicate that siRNAs form complexes with all the dendrimers tested. Oligoribonucleotide duplexes can be released from dendriplexes after heparin treatment and the structure of siRNA is maintained in the case of PAMAM or carbosilane dendrimers. The dendrimers were also effective in protecting siRNA from RNase A activity. The selection of the best siRNA carrier will be made based on cell culture studies (Part B).
Keywords: Dendrimer; Anticancer siRNA; Complex formation; Biophysical characteristics; Nano-drug-delivery;
Multifunctional network-structured film coating for woven and knitted polyethylene terephthalate against cardiovascular graft-associated infections by Bassam M. Al Meslmani; Gihan F. Mahmoud; Frank O. Sommer; Michael D. Lohoff; Udo Bakowsky (270-276).
Display OmittedMultifunctional network-structured polymeric coat for woven and knitted forms of crimped polyethylene terephthalate PET graft was developed to limit graft-associated infections. A newly synthesized antibacterial sulfadimethoxine polyhexylene adipate-b-methoxy polyethylene oxide (SD-PHA-b-MPEO) di-block copolymer was employed. Our figures of merit revealed that the formed coat showed a porous topographic architecture which manifested paramount properties, mostly bacterial anti-adhesion efficiency and biocompatibility with host cells. Compared to untreated grafts, the coat presented marked reduction of adhered Gram-positive Staphylococcus epidermidis previously isolated from a patient's vein catheter by 2.6 and 2.3 folds for woven and knitted grafts, respectively. Similarly, bacterial anti-adhesion effect was observed for Staphylococcus aureus by 2.3 and 2.4 folds, and by 2.9 and 2.7 folds for Gram-negative Escherichia coli for woven and knitted grafts, respectively. Additionally, adhesion and growth characteristics of L929 cells on the modified grafts revealed no significant effect on the biocompatibility. In conclusion, coating of PET with (SD-PHA-b-MPEO) is a versatile approach offers the desired bacterial anti-adhesion effect and host biocompatibility.
Keywords: Network-structured polymeric coat; Crimped polyethylene terephthalate; Modified grafts; Bacterial anti-adhesion; Biocompatibility;
Influence of excipients on solubility and dissolution of pharmaceuticals by Raphael Paus; Anke Prudic; Yuanhui Ji (277-287).
Display OmittedIn this work, solubilities and dissolution profiles of the active pharmaceutical ingredients (APIs) indomethacin and naproxen were measured in water in the presence of one excipient out of polyethylene glycol (PEG) 2000, 6000 and 12000, polyvinylpyrrolidone (PVP) K 25 and mannitol. It was found that the solubility of indomethacin and naproxen was increased with an addition of the selected excipients, which was also predicted by the perturbed-chain statistical associating fluid theory (PC-SAFT). The two-step chemical-potential-gradient model was applied to investigate the dissolution mechanism of indomethacin and naproxen in water in the presence of the excipient. It was found that the dissolution mechanisms of indomethacin and naproxen were changed by the presence of excipients. Although the solubility of the API was increased by the addition of excipients, the dissolution rate of the API was decreased in some cases. This was mainly due to the combination of the molecular interactions between the API and the polymer with the influence of the excipients on the kinetic part (rate constant of the surface reaction or diffusion of the API or both) of API dissolution as function of PEG molar mass as well as of the API type. Based upon the determined rate constants, the dissolution profiles were modeled with a high accuracy compared with the experimental data.
Keywords: Dissolution; Excipients; Thermodynamics; Solubility; PC-SAFT; Chemical potential gradient; Poorly soluble APIs;
Anticancer siRNA cocktails as a novel tool to treat cancer cells. Part (B). Efficiency of pharmacological action by Volha Dzmitruk; Aleksandra Szulc; Dzmitry Shcharbin; Anna Janaszewska; Natallia Shcharbina; Joanna Lazniewska; Darya Novopashina; Marina Buyanova; Maksim Ionov; Barbara Klajnert-Maculewicz; Rafael Gómez-Ramirez; Serge Mignani; Jean-Pierre Majoral; Maria Angeles Muñoz-Fernández; Maria Bryszewska (288-294).
Display OmittedThis paper examines a perspective to use newly engineered nanomaterials as effective and safe carriers for gene therapy of cancer. Three different groups of cationic dendrimers (PAMAM, phosphorus, and carbosilane) were complexed with anticancer siRNA and the biophysical properties of the dendriplexes created were analyzed. The potential of the dendrimers as nanocarriers for anticancer Bcl-xl, Bcl-2, Mcl-1 siRNAs and additionally a scrambled sequence siRNA has been explored. Dendrimer/siRNA complexes were characterised by various methods including fluorescence, zeta potential, dynamic light scattering, circular dichroism, gel electrophoresis and transmission electron microscopy. In this part of study, the transfection of complexes in HeLa and HL-60 cells was analyzed using both single apoptotic siRNAs and a mixture (cocktail) of them. Cocktails were more effective than single siRNAs, allowing one to decrease siRNAs concentration in treating cells. The dendrimers were compared as siRNA carriers, the most effective being the phosphorus-based ones. However, they were also the most cytotoxic on their own, so that in this regard the application of all dendrimers in anticancer therapy will be discussed.
Keywords: Dendrimer; Anticancer siRNA; Nano-drug-delivery; Cancer cells;
Optimization of a PGSS (particles from gas saturated solutions) process for a fenofibrate lipid-based solid dispersion formulation by Aude Pestieau; Fabrice Krier; Pierre Lebrun; Adeline Brouwers; Bruno Streel; Brigitte Evrard (295-305).
Display OmittedThe aim of this study was to develop a formulation containing fenofibrate and Gelucire® 50/13 (Gattefossé, France) in order to improve the oral bioavailability of the drug. Particles from gas saturated solutions (PGSS) process was chosen for investigation as a manufacturing process for producing a solid dispersion. The PGSS process was optimized according to the in vitro drug dissolution profile obtained using a biphasic dissolution test.Using a design of experiments approach, the effects of nine experimental parameters were investigated using a PGSS apparatus provided by Separex® (Champigneulles, France).Within the chosen experimental conditions, the screening results showed that the drug loading level, the autoclave temperature and pressure, the connection temperature and the nozzle diameter had a significant influence on the dissolution profile of fenofibrate. During the optimization step, the three most relevant parameters were optimized using a central composite design, while other factors remained fixed. In this way, we were able to identify the optimal production conditions that would deliver the highest level of fenofibrate in the organic phase at the end of the dissolution test. The closeness between the measured and the predicted optimal dissolution profiles in the organic phase demonstrated the validity of the statistical analyses.
Keywords: Supercritical carbon dioxide; Solid dispersion; Biphasic dissolution test; Particles from gas saturated solutions; Design of experiments; Fenofibrate;
Triboelectrification and dissolution property enhancements of solid dispersions by Kofi Asare-Addo; Enes Šupuk; Hiba Al-Hamidi; Samuel Owusu-Ware; Ali Nokhodchi; Barbara R. Conway (306-316).
Dissolution and tribo-electrification of indomethacin: glucosamine solid dispersions.Display OmittedThe use of solid dispersion techniques to modify physicochemical properties and improve solubility and dissolution rate may result in alteration to electrostatic properties of particles. Particle triboelectrification plays an important part in powder processing, affecting end product quality due to particle deposition and powder loss. This study investigates the use of glucosamine hydrochloride (GLU) in solid dispersions with indomethacin. Solvents selected for the preparation of the dispersions were acetone, acetone–water, ethanol and ethanol–water. Solid state characterizations (DSC, FTIR and XRPD) and dissolution were conducted. Dispersions were subjected to charge using a custom built device based on a shaking concept, consisting of a Faraday cup connected to an electrometer. All dispersions improved the dissolution rate of indomethacin. Analysis showed the method of preparation of the dispersion induced polymorphic forms of the drug. Indomethacin had a high propensity for charging (−411 nC/g). GLU had a very low charge (−1 nC/g). All dispersions had low charges (−1 to 14 nC/g). Acetone as a solvent, or in combination with water, produced samples with an electronegative charge in polarity. The same approach with ethanol produced electropositive charging. The results show the selection of solvents can influence powder charge thereby improving powder handling as well as dissolution properties.
Keywords: Electrostatics; Solid dispersions; Triboelectrification; Indomethacin; d-Glucosamine HCl; Polymorphism;
Key-properties outlook of a levofloxacin-loaded acrylic bone cement with improved antibiotic delivery by Ana C. Matos; Isabel A.C. Ribeiro; Rita C. Guedes; Rosana Pinto; Mário A. Vaz; Lídia M. Gonçalves; António J. Almeida; Ana F. Bettencourt (317-328).
Display OmittedAntibiotic-loaded acrylic bone cements (ALABCs) are widely used to decrease the occurrence of bone infections in cemented arthroplasties and actually being considered as a more cost-effective procedure when compared to cementless implants. However, ALABCs have a major drawback, which is the incomplete release of the antibiotics and, as a result, pathogens that commonly are responsible for those infections are becoming resistant. Consequently, it is of most relevance to find new antibacterial agents to load into BC with an effective mechanism against those microorganisms. This research work intended to load levofloxacin, a fluoroquinolone with anti-staphylococcal activity and adequate penetration into osteoarticular tissues, on lactose-modified commercial bone cement (BC). This modified BC matrix exhibited increased levofloxacin release and delayed Staphylococcus aureus biofilm formation. Further insights on material-drug interaction during BC setting were investigated by density functional theory calculations. The obtained results suggested that favorable covalent and non-covalent interactions could be established between levofloxacin and the BC. Moreover, BC mechanical and biocompatibility properties were maintained. These features justify the potential of levofloxacin-loaded modified-BC as a valuable approach for local antibiotic delivery in bone infections management.
Keywords: Poly(methylmethacrylate); Fluoroquinolone; Staphylococcus-infection; Controlled release; Density functional theory;
Investigating the potential of employing bilosomes as a novel vesicular carrier for transdermal delivery of tenoxicam by Abdulaziz M. Al-mahallawi; Aly A. Abdelbary; Mona H. Aburahma (329-340).
Display OmittedBilosomes represent an evolving vesicular carrier that have been explored for oral vaccines delivery based on its ability to resist enzymes and bile salts in the gastrointestinal tract (GIT). Bilosomes vesicles are formed of bilayer membrane of non-ionic surfactant molecules encompassing bile salts. Although, bilosomes have not been proposed for transdermal drug delivery, this carrier seems to have promising potential in this regard. Accordingly, the aim of this investigation was to assess the capability and safety of utilizing bilosomes for transdermal delivery of tenoxicam (TX) as a model drug. A 3122 full factorial design was adopted to study the effects of different formulation parameters on bilosomes properties and select the optimal formulation using Design-Expert® software. The selected formulation displayed nano-sized spherical vesicles (242.5 ± 6.43 nm) with reasonable entrapment efficiency percent (68.33 ± 2.33%). Confocal laser scanning microscopy confirmed the capability of the flourolabeled bilosomes to penetrate deep within the skin. Both, ex vivo permeation and in vivo skin deposition studies confirmed the superiority of bilosomes over drug solution in delivering TX transdermally. In addition, in vivo histopathological study proved the safety of topically applied bilosomes. In summary, the highlighted results confirmed that bilosomes can be further adopted for delivering drugs transdermally.
Keywords: Bilosomes; Bile salts; Histopathology; Ex vivo permeation; In vivo skin deposition; Confocal laser scanning microscopy;
Migrability of PVC plasticizers from medical devices into a simulant of infused solutions by L. Bernard; R. Cueff; C. Breysse; B. Décaudin; V. Sautou (341-347).
Display OmittedMedical devices (MD) for infusion and artificial nutrition are essentially made of plasticized PVC. The plasticizers in the PVC matrix can leach out into the infused solutions and may enter into contact with the patients. In order to assess the risk of patient exposure to these plasticizers we evaluated the migration performance of DEHP, DEHT, DINCH, and TOTM using a model adapted to the clinical use of the MDs. Each PVC tubing sample was immersed in a simulant consisting of a mixture of ethanol/water (50/50 v/v) at 40 °C and migration tests were carried out after 24 h, 72 h, and 10 days.DEHP had the highest migration ability, which increased over time. The amount of TOTM released was more than 20 times less than that of DEHP, which makes it an interesting alternative. DEHT is also promising, with a migration level three times smaller than DEHP. However, the migration ability of DINCH was similar to DEHP, with the released amounts equaling 1/8th of the initial amount in the tubing after 24 h of contact. Taking into account the available toxicological data, TOTM and DEHT appear to be of particular interest. However, these data should be supplemented and correlated with clinical and toxicological studies on plasticizers and their metabolites.
Co-processing of hydroxypropyl methylcellulose (HPMC) for improved aqueous dispersibility by Payal Sharma; Sameer R. Modi; Arvind K. Bansal (348-356).
Display OmittedHydroxypropyl methylcellulose (HPMC), a widely employed film coating polymer, exhibits poor dispersibility in an aqueous medium. Rapid hydration leading to swelling and coherent gel formation is reported to be responsible for this problem. Present study focuses on the use of spray drying based approach for co-processing of HPMC to improve its dispersibility. Dispersion behavior of native HPMC showed formation of large lumps that did not dissolve completely for 40 min. However, HPMC co-processed with lactose and sodium chloride exhibited improvement in dispersibility with complete dissolution attained within 20 min. Mechanistic insights into improved dispersibility were obtained using contact angle studies, confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM) and scanning TEM (STEM) studies. Co-processed products exhibited higher immersional wetting as determined by sessile drop contact angle technique, which indicated spontaneous incursion of water. CLSM study revealed highly swollen and erodible gel in co-processed products. Novel application of TEM and STEM techniques was developed to understand the nature of mixing achieved during co-processing. Overall the improvement in dispersibility of co-processed products was predominantly due to the alteration in sub-particulate level properties during co-processing. The effect of excipients on the film properties of HPMC, like tensile strength and hygroscopicity, was also assessed. This study provides the comprehensive understanding of role of co-processing on improvement of dispersion behavior of HPMC and helps in the selection of suitable excipients for the same.
Keywords: Hydroxypropyl methylcellulose (HPMC); Co-processing; Dispersion; Gel layer; Swelling; Microscopic techniques;
Self-assembled filomicelles prepared from polylactide/poly(ethylene glycol) block copolymers for anticancer drug delivery by Katarzyna Jelonek; Suming Li; Xiaohan Wu; Janusz Kasperczyk; Andrzej Marcinkowski (357-364).
Display OmittedBioresorbable filomicelles present many advantageous as drug delivery systems e.g., long circulation time and high loading efficiency. The aim of this study was to develop polylactide/poly(ethylene glycol) (PLA/PEG) filomicelles for drug delivery applications. A series of PLA/PEG diblock copolymers were synthesized using non-toxic initiator, and characterized by means of NMR and GPC. Analysis of morphology of micelles determined by TEM revealed that apart from the weight fraction also the molar mass of PEG and the stereochemistry of PLA block must be considered for tailoring micellar structures. The CMC was found to be dependent on the length and structure of the hydrophobic block. It was observed that the drug loading properties could be improved by selection of appropriate copolymer and encapsulation method. Slower release of paclitaxel was observed for mPEG5000 initiated copolymers than mPEG2000 initiated copolymers. Moreover, the influence of the length of hydrophobic block and its stereoisomeric form on drug release rate was evidenced. Therefore, PLA/PEG filomicelles with good stability, high drug loading capacity and sustained drug release appear most attractive for drug delivery applications.
Keywords: Polymeric micelles; Filomicelles; Paclitaxel; PLA/PEG; Drug delivery;
Comparative evaluation of polymeric and waxy microspheres for combined colon delivery of ascorbic acid and ketoprofen by F. Maestrelli; N. Zerrouk; M. Cirri; P. Mura (365-373).
Display OmittedThe goal of this work was to combine the ketoprofen anti-inflammatory effect with the ascorbic acid antioxidant properties for a more efficient treatment of colonic pathologies. With this aim, microspheres (MS) based on both waxy materials (ceresine, Precirol® and Compritol®) or hydrophilic biopolymers (pectine, alginate and chitosan) loaded with the two drugs were developed, physicochemically characterized and compared in terms of entrapment efficiency, in vitro release profiles, potential toxicity and drug permeation properties across the Caco-2 cell line. Waxy MS revealed an high encapsulation efficiency of ketoprofen but a not detectable entrapment of ascorbic acid, while polymeric MS showed a good entrapment efficiency of both drugs. All MS need a gastro-resistant coating, to avoid any premature release of the drugs. Ketoprofen release rate from polymeric matrices was clearly higher than from the waxy ones. In contrast, the ASC release rate was higher, due to its high hydro-solubility. Cytotoxicity studies revealed the safety of all the formulations. Transport studies showed that the ketoprofen apparent permeability increased, when formulated with the different MS. In conclusion, only polymeric MS enabled an efficient double encapsulation of both the hydrophilic and lipophilic drugs, and, in addition, presented higher drug release rate and stronger enhancer properties.
Keywords: Ketoprofen; Ascorbic acid; Colon delivery; Microspheres; Caco-2 cells;
Temperature-dependent drug release from DPPC:C12H25-PNIPAM-COOH liposomes: Control of the drug loading/release by modulation of the nanocarriers’ components by Natassa Pippa; Anastasia Meristoudi; Stergios Pispas; Costas Demetzos (374-382).
Display OmittedNovel polymer-modified thermosensitive liposomes were developed for the delivery of indomethacin in order to control its release profile. When attached to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, the end functionalized C12H25-poly(N-isopropylacrylamide)-COOH (C12H25-PNIPAM-COOH) polymer was membrane-disruptive in a temperature-dependent manner. The interest for this polymer is driven by its famous lower critical solution temperature (LCST) behavior, where heating an aqueous solution of PNIPAM above 32 °C induces nanophase separation and polymer chain aggregation. The physicochemical/structural behavior of these polymer-modified thermosensitive liposomes was found to depend on the PNIPAM:lipid molar ratio and the composition of the polymeric guest. The incorporation of PNIPAM has caused alterations in the thermotropic behavior of DPPC liposomes, as the differential scanning calorimetry (DSC) experiments revealed. The drug loading and the release were found to be strongly dependent on the thermotropic characteristics of the PNIPAM grafted DPPC liposomes. Namely, the in vitro release is immediate at 37 °C (>LCST) (“burst” effect), while the prepared mixed nanocarriers did not release the encapsulated bioactive substance at <32 °C (<LCST). Thus, the thermosensitivity and the drug loading/release properties of the prepared formulations can be modulated by varying the ratio of DPPC/PNIPAM components, as well as the molecular characteristics of the polymeric guest.
Keywords: Poly(N-isopropylacrylamide); Thermosensitive liposomes; Drug release; Burst “effect”; Differential scanning calorimetry;
Corrigendum to ‘Preclinical evaluation of a ricinoleic acid poloxamer gel system for transdermal eyelid delivery’ [Int. J. Pharm. 470 (1–2) (2014) 158–161] by Sai H.S. Boddu; Himanshu Gupta; Sindhu Prabha Bonam (383).