International Journal of Pharmaceutics (v.403, #1-2)
Editorial Board (iii).
Velocity profiles and shear strain rate variability in the USP Dissolution Testing Apparatus 2 at different impeller agitation speeds by Ge Bai; Yimin Wang; Piero M. Armenante (1-14).
The fluid velocity profiles at different locations inside a standard USP Dissolution Testing Apparatus 2 were experimentally obtained via Laser Doppler Velocimetry (LDV) at three impeller agitations speeds, namely 50 rpm, 75 rpm and 100 rpm. The experimental results were compared with the predictions obtained with Computational Fluid Dynamics (CFD) where the κ–ω model with low Reynolds number correction was used to account for turbulence effects. In general, good agreement was found between the experimental LDV velocity measurements and the CFD simulation predictions. The non-dimensional tangential, axial and radial velocity profiles (scaled with the impeller tip speed) and the flow pattern were found to be nearly independent of the agitation speed in most regions of the vessel, implying that increasing the agitation speed generally produced a corresponding increase in the local values of the velocity. However, the velocity profiles and flow pattern in the inner core region just below the impeller, where the dissolving tablet is usually located, were found to be much less sensitive to agitation speed. In this region, the axial and radial velocities were especially low and were not significantly affected by agitation increases. This inner core region at the center of the vessel bottom persisted irrespective of agitation intensity. The CFD predictions also indicated that increasing the agitation speed resulted in a higher shear strain rate distribution along the vessel bottom, although the strain rate was always very low at the center of the vessel bottom, even when the agitation speed was increased.
Keywords: Dissolution testing; USP Dissolution Testing Apparatus 2; Hydrodynamics; Computational Fluid Dynamics (CFD); Laser Doppler Velocimetry (LDV); Agitation speed; Velocity profiles; Shear strain rate;
Confocal laser scanning microscopy (CLSM) based evidence for cell permeation by mono-4-(N-6-deoxy-6-amino-β-cyclodextrin)-7-nitrobenzofuran (NBD-β-CyD) by Hai Wei; Weizhong Zheng; James Diakur; Leonard I. Wiebe (15-22).
Beta-cyclodextrin (β-CyD), amantadine and glucose were fluorescently tagged with 4-chloro-7-nitrobenz-2-oxa-1,3-diazole (NBD chloride) to afford NBD-β-CyD, NBD-amantadine and NBD-glucose, respectively. NBD-β-CyD/amantadine and β-CyD/NBD-amantadine inclusion complexes were prepared. Fluorescence emission maxima (λ max 544 nm) and relative fluorescence intensities for NBD-β-CyD and NBD-β-CyD/amantadine were virtually identical, precluding the use of emission spectrum shifts for distinguishing free NBD-β-CyD from the complex. Intracellular accumulation of NBD-β-CyD was studied in HepG2 and SK-MEL-24 cells using confocal laser scanning microscopy (CLSM). No major differences were observed between uptake of NBD-β-CyD and NBD-β-CyD/amantadine. Serum proteins did not perturb uptake, whereas temperature-dependent uptake, indicative of cell entry via diffusion, was observed. Intracellular distribution favoured mitochondria, with less fluorescent material present in cytoplasm and none in cell nuclei. No experimental evidence of NBD-β-CyD breakdown to NBD-glucose was found upon chromatographic analysis of incubation mixtures, providing additional evidence of intact NBD-β-CyD entry into these cells. Endocytosis and/or cholesterol-independent membrane modulation are discussed as possible mechanisms for the transmembrane passage of NBD-β-CyD.
Keywords: β-Cyclodextrin; NBD-adamantine; NBD-glucose; 4-Chloro-7-nitrobenz-2-oxa-1,3-diazole (NBD); Confocal laser scanning microscopy (CLSM); Intracellular uptake in vitro;
Changed crystallinity of mebendazole solid dispersion: Improved anthelmintic activity by Juan J. García-Rodriguez; Paloma M. de la Torre-Iglesias; M. Carmen Vegas-Sánchez; Susana Torrado-Durán; Francisco Bolás-Fernández; Santiago Torrado-Santiago (23-28).
To improve the efficacy of mebendazole (MBZ), a poorly water-soluble drug, MBZ solid dispersions containing different proportions of low-substituted hydroxypropylcellulose (L-HPC) were prepared by lyophilization process. The physical characteristics of recrystallized MBZ, and solid dispersions (SD) at different MBZ:L-HPC proportions were investigated in terms of morphology (scanning electron microscopy, SEM), powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and dissolution rate. The in vivo performance was assessed by anthelmintic activity studies against enteral (pre-adult) stage of Trichinella spiralis in mice. The XRD, DSC and SEM revealed a characteristic decrease in crystallinity when increasing the L-HPC proportions in the solid dispersions. The dissolution studies demonstrated a marked increase in the dissolution rate in comparison with recrystallized drug. The considerable improvement in the dissolution rate of MBZ from solid dispersions was attributed to decreased drug crystallinity and altered surface morphology (major) and to the wetting effect of L-HPC (minor). The in vivo studies revealed that the anthelmintic effects of solid dispersions in mice were significantly increased in comparison with recrystallized MBZ (1.74-fold for SD-1:1, 3.20-fold for SD-1:2.5 and 3.80-fold for SD-1:5). These results have shown the suitability of MBZ:L-HPC solid dispersions for the treatment of enteral helmintic diseases at low doses.
Keywords: Mebendazole; Solid dispersions; Powder X-ray diffraction; Dissolution rate; Anthelmintic activity;
Thermal analysis: A further step in characterizing solid forms obtained by screening crystallization of an API by Thibaud Detoisien; Marine Arnoux; Pascal Taulelle; Didier Colson; Jean Paul Klein; Stéphane Veesler (29-36).
Phase and habit selection is a very important step in the early stages of pharmaceutical development of new APIs. In this paper, we show how observation, diffraction and thermal analysis are complementary methods of solid habit and phase characterization. At the end of phase screening of an API several habits and phases can be discriminated by microscopy, XRPD or Raman spectroscopy. Using thermal methods here allows us to separate the 12 phases discriminated by XRPD into: anhydrous, monohydrate, organic monosolvate and heterosolvate phases.
Keywords: Crystallization; Polymorphism; Thermal analysis;
Excipients enhance intestinal absorption of ganciclovir by P-gp inhibition: Assessed in vitro by everted gut sac and in situ by improved intestinal perfusion by Ming Li; Luqin Si; Hongping Pan; Abdullah K. Rabba; Fang Yan; Jun Qiu; Gao Li (37-45).
In rats we examined the effects of some common excipients on the intestinal absorption of ganciclovir (GCV), a BCS-III drug and substrate of P-gp, by assessing its in vitro transfer from mucosa to serosa and in situ transepithelial permeation. In vitro, all selected excipients (concentration range 0.1–1% [w/v]) could increase the transport amount of GCV in the everted gut sac model. Whereas enhancement by F-68 demonstrated regional differences like verapamil, PEG-400, Tween-80 and EL-35 exhibited no regional differences. In situ studies were performed by an improved perfusion model, single-pass perfusion with whole small intestine, to determine more accurately the permeability of lipophobic compounds. The permeability of GCV was significantly increased by all excipients. The effects of EL-35 and F-68 were dose-dependent but those of PEG-400 and Tween-80 were not. The results suggest that enhancements of intestinal absorption of GCV by these excipients are probably due to inhibition of P-gp-mediated drug efflux. It could be deduced from their different properties that both blocking binding sites of P-gp and altering membrane fluidity were involved in their P-gp-inhibition. The former mechanism might be involved for F-68, while the latter one might account for the effects of PEG-400, Tween-80 and EL-35.
Keywords: P-glycoprotein; Excipient; Everted gut sac; Single-pass intestinal perfusion; BCS-III drug;
Nanocarrier for the enhanced bioavailability of a cardiovascular agent: In vitro, pharmacodynamic, pharmacokinetic and stability assessment by Vikas Bali; Mushir Ali; Javed Ali (46-56).
In vivo bioavailability studies in rats indicate significant improvement (p < 0.001) in the absorption of ezetimibe from nanoemulsion CF1 over marketed tablet and suspension formulation.The goals of the current study were to develop and characterize a nanoemulsion of ezetimibe, evaluate its stability, lipid lowering and pharmacokinetic profile. Solubility of the drug was estimated in various oils and surfactants. Existence of nanoemulsion region was confirmed by plotting phase diagrams. Various thermodynamic stability and dispersibility tests were performed on the formulations chosen from phase diagram. Percentage transmittance, refractive index, viscosity, droplet size and zeta potential of the optimized formulations were determined. Dialysis bag method was employed to study the release rate. The formulation selected for bioavailability estimation contained Capryol 90 (10%, v/v), Crempophor EL (11.25%, v/v), Transcutol® P (33.75%, v/v), and double distilled water (45%, v/v). The release rate from the nanoemulsion was highly significant (p < 0.001) in contrast to the drug suspension. The level of total cholesterol in the group receiving nanoemulsion CF1 was found to be highly significant (p < 0.001) in comparison to the group receiving drug suspension. Bioavailability studies in rats revealed superior absorption of ezetimibe from nanoemulsion as compared to the marketed formulation and drug suspension. The shelf life of the nanoemulsion was estimated to be 18.53 months. The present study corroborated nanoemulsion to be a promising choice to improve the bioavailability of ezetimibe.
Keywords: Nanoemulsion; Oral bioavailability; Ezetimibe; Pseudoternary phase diagram; Stability;
Noninvasive and persistent transfollicular drug delivery system using a combination of liposomes and iontophoresis by Kazuaki Kajimoto; Masahiko Yamamoto; Misuzu Watanabe; Kaoru Kigasawa; Kiyoshi Kanamura; Hideyoshi Harashima; Kentaro Kogure (57-65).
Iontophoresis is a promising technique for enhancing transdermal administration of charged drugs. However, conventional iontophoresis is not sufficient for effective delivery of large, hydrophilic, or electrically neutral molecules. In this study, we utilized charged liposomes as carriers, focused on a transfollicular route for delivery of the liposomes, and optimized iontophoretic conditions and lipid composition for this method in both in vitro and in vivo conditions. As a result, we identified the optimum condition (lipid composition: DOTAP/EPC/Chol = 2:2:1, current supply: 0.45 mA/cm2, duration: 1 h) for effective iontophoretic delivery of aqueous solution, which cannot be transferred into the skin without charged liposomes. We also examined the pharmacological effects of iontophoresis of liposomes encapsulating insulin (INS-lipo) using a rat model of type I diabetes. Interestingly, iontophoresis of INS-lipo onto a diabetes rat skin resulted in a gradual decrease in blood glucose levels, with levels reaching 20% of initial values at 18 h after administration. These lower blood glucose levels were maintained for up to 24 h. Significant amount of insulin were also detected in plasma 18 h after iontophoresis of INS-lipo. We succeeded in developing a non-invasive and persistent transfollicular drug delivery system that used a combination of liposomes and iontophoresis.
Keywords: Liposomes; Iontophoresis; Transdermal delivery; Insulin; Diabetes;
In line NIR quantification of film thickness on pharmaceutical pellets during a fluid bed coating process by Min-Jeong Lee; Da-Young Seo; Hea-Eun Lee; In-Chun Wang; Woo-Sik Kim; Myung-Yung Jeong; Guang J. Choi (66-72).
Along with the risk-based approach, process analytical technology (PAT) has emerged as one of the key elements to fully implement QbD (quality-by-design). Near-infrared (NIR) spectroscopy has been extensively applied as an in-line/on-line analytical tool in biomedical and chemical industries. In this study, the film thickness on pharmaceutical pellets was examined for quantification using in-line NIR spectroscopy during a fluid-bed coating process. A precise monitoring of coating thickness and its prediction with a suitable control strategy is crucial to the quality assurance of solid dosage forms including dissolution characteristics.Pellets of a test formulation were manufactured and coated in a fluid-bed by spraying a hydroxypropyl methylcellulose (HPMC) coating solution. NIR spectra were acquired via a fiber-optic probe during the coating process, followed by multivariate analysis utilizing partial least squares (PLS) calibration models. The actual coating thickness of pellets was measured by two separate methods, confocal laser scanning microscopy (CLSM) and laser diffraction particle size analysis (LD-PSA). Both characterization methods gave superb correlation results, and all determination coefficient (R 2) values exceeded 0.995. In addition, a prediction coating experiment for 70 min demonstrated that the end-point can be accurately designated via NIR in-line monitoring with appropriate calibration models. In conclusion, our approach combining in-line NIR monitoring with CLSM and LD-PSA can be applied as an effective PAT tool for fluid-bed pellet coating processes.
Keywords: Fluid-bed coating; Coating thickness; PAT; NIR; Pellets; CLSM; PSA;
Sodium carboxymethylcellulose scaffolds and their physicochemical effects on partial thickness wound healing by Nor Amlizan Ramli; Tin Wui Wong (73-82).
Sodium carboxymethylcellulose (SCMC) scaffolds promote wound healing through modulating transepidermal water movement as a function of polymer molecular weight instead of carboxymethyl substitution degree or matrix pore size distribution.This study investigated critical physicochemical attributes of low (LV), medium (MV) and high molecular weight (HV) sodium carboxymethylcellulose (SCMC) scaffolds in partial thickness wound healing. SCMC scaffolds were prepared by solvent-evaporation technique. Their in vitro erosion, moisture affinity, morphology, tensile strength, polymer molecular weight and carboxymethyl substitution, and in vivo wound healing profiles were determined. Inferring from rat wound size, re-epithelialization and histological profiles, wound healing progressed with HV scaffold > LV–MV scaffold > control with no scaffold. The transepidermal water loss (TEWL) from wound of rats treated by control > HV scaffold > LV–MV scaffold. HV scaffold had the highest tensile strength of all matrices and was resistant to erosion in simulated wound fluid. In spite of constituting small nanopores, it afforded a substantial TEWL than MV and LV scaffolds from wound across an intact matrix through its low moisture affinity characteristics. The HV scaffold can protect moisture loss without its excessive accumulation at wound bed which hindered re-epithelialization process. Regulation of transepidermal water movement and wound healing by scaffolds was governed by SCMC molecular weight instead of its carboxymethyl substitution degree or matrix pore size distribution, with large molecular weight HV preferred over lower molecular weight samples.
Keywords: Sodium carboxymethylcellulose; Transepidermal water loss; Wound dressing; Wound healing;
Determination of acetaminophen's solubility in poly(ethylene oxide) by rheological, thermal and microscopic methods by Min Yang; Peng Wang; Herman Suwardie; Costas Gogos (83-89).
The solubility of acetaminophen (APAP) in poly(ethylene oxide) (PEO) at different temperatures was measured utilizing rheological analysis, hot-stage microscopy and differential scanning calorimetry (DSC).A drug's solubility in a polymeric excipient is an important parameter that dictates the process window of hot-melt extrusion (HME) and product stability during storage. However, it is rather challenging to experimentally determine the solubility and there is very few published work in this field. In this study, the solubility of a model drug acetaminophen (APAP) in a pharmaceutical grade polymer poly(ethylene oxide) (PEO) at HME processing temperature was measured utilizing rheological analysis, hot-stage microscopy and differential scanning calorimetry (DSC). The results from three methods were consistent and the solubility was found to increase from 14% at 80 °C to 41% at 140 °C. The apparent drug solubility at room temperature was estimated to be less than 10% through glass transition temperature (T g) measurement using DSC and dynamic mechanical thermal analysis (DMTA). A “phase diagram” was constructed based on the experimental data and could be explored to design the HME process and formulation. Very few assumptions were made in the experimental study and result analysis, and the methods described here can be applied to investigate other drug–polymer systems to obtain the important thermodynamic data.
Keywords: Hot-melt mixing; Solubility; Rheology; Glass transition; Acetaminophen/paracetamol; Poly(ethylene oxide) (PEO);
Modeling of small-molecule release from crosslinked hydrogel microspheres: Effect of crosslinking and enzymatic degradation of hydrogel matrix by Felice Cheng; Young Bin Choy; Hyungsoo Choi; Kyekyoon (Kevin) Kim (90-95).
A diffusion-based model describing the drug release from a charged hydrogel (gelatin) microsphere undergoing enzymatic degradation is presented. The model elucidates the effect of glutaraldehyde, a crosslinking agent, on the release profile in terms of the initial drug distribution, diffusivity of the drug, degradation rate of gelatin and its ability to form polyionic complex with the drug. The model was validated by comparing with in vitro release of trypan blue, an acidic model drug, from basic gelatin microspheres. While drug release was not a simple function of glutaraldehyde concentration, the effective diffusivity was found to be inversely proportional to glutaraldehyde concentration in the form of a power function when the initial drug distribution was taken into consideration. For these reasons, the present model can accurately predict drug release with no adjustable parameters, given the collagenase concentration. The present model may help design certain release scenarios from biodegradable charged hydrogels for the oppositely charged drugs and biomolecules.
Keywords: Gelatin; Crosslinking; Controlled release; Michaelis–Menten equation; Degradation; Reaction diffusion;
Solubility and partitioning of carbamazepine in a two-phase supercritical carbon dioxide/polyvinylpyrrolidone system by Shweta Ugaonkar; Thomas E. Needham; Geoffrey D. Bothun (96-100).
Porosity of PVP microparticles aids surface adsorption of the anticonvulsant drug carbamazepine in a two-phase scCO2/PVP system.Supercritical carbon dioxide (scCO2) processing of drug/polymer mixtures is an environmentally friendly means of creating an impregnated polymeric carrier to enhance the aqueous dissolution rate of drugs that exhibit poor water solubility or are thermally labile. However, the role of drug solubilization and its interaction with the polymer during scCO2 processing on the extent and rate of dissolution has been ambiguous. In this study, we examine the rate of dissolution of carbamazepine (CBZ), a hydrophobic drug for treating epilepsy, in scCO2 (90–200 bar, 35 °C and 45 °C) and its partitioning into polyvinylpyrrolidone (PVP, 10 and 29 K MW) using in situ UV–vis spectroscopy. Our results show that partitioning occurs by surface adsorption and impregnation within the polymer matrix. These processes are linked to plasticization, which is dependent on PVP molecular weight, and temperature and pressure during treatment. The rate and extent of CBZ solubility is also controlled by treatment condition. The ability to tune polymer and drug simultaneously can be used to control the nature and extent of drug loading.
Keywords: Carbamazepine; Supercritical; Excipient; Formulation; Polymer swelling; Drug partitioning;
In vitro aerosol characterization of Staccato® Loxapine by Khe Dinh; Dan J. Myers; Marc Glazer; Tamara Shmidt; Caitlin Devereaux; Kathleen Simis; Peter D. Noymer; Min He; Corinna Choosakul; Qiang Chen; James V. Cassella (101-108).
Average emitted dose for the Staccato® Loxapine for inhalation product characterized at different operating settings and at nominal test conditions following exposure to various stresses.Medicinal aerosol products (metered dose and dry powder inhalers) require characterization testing over a wide range of use and pre-operating stress scenarios in order to ensure robust product performance and support submissions for regulatory approval. Aerosol characterization experiments on Staccato® Loxapine for inhalation (Staccato Loxapine) product (emitted dose, particle size, and purity) were assessed at different operating settings (flow rates, ambient temperature and humidity, altitude, and orientation) and at nominal test conditions following exposure to various stresses on the device (mechanical shock, vibration, drop, thermal cycling, and light exposure). Emitted dose values were approximately 90% of the coated dose at every condition, meeting target specifications in each case. Aerosol purity was consistently >99.5% for every test setting, with no reportable impurities according to ICH standards (>0.1%). Particle size averaged 2 μm (MMAD) and was independent of the different test conditions with the exception of different airflow rates. Particle size decreased slightly with airflow, which may assist in maintaining constant deep lung deposition. The combination of high emitted dose efficiency and a particle size range ideally suited for lung deposition, along with the consistency of these key aerosol attributes, suggests that the Staccato system has distinct advantages over more traditional aerosol systems.
Keywords: Aerosol; Characterization; Emitted dose; Particle size; Purity;
Prediction of mechanical properties of compacted binary mixtures containing high-dose poorly compressible drug by Sarsvatkumar Patel; Arvind Kumar Bansal (109-114).
The aim of the study was to develop, compare and validate predictive model for mechanical property of binary systems. The mechanical properties of binary mixtures of ibuprofen (IBN) a poorly compressible high dose drug, were studied in presence of different excipients. The tensile strength of tablets of individual components viz. IBN, microcrystalline cellulose (MCC), and dicalcium phosphate dihydrate (DCP) and binary mixtures of IBN with excipients was measured at various relative densities. Prediction of the mechanical property of binary mixtures, from that of single components, was attempted using Ryshkewitch–Duckworth (R-D) and Percolation theory, by assuming a linear mixing rule or a power law mixing rule. The models were compared, and the best model was proposed based on the distribution of residuals and the Akaike's information criterion. Good predictions were obtained with the power law combined with linear mixing rule, using R-D and Percolation models. The results indicated that the proposed model can well predict the mechanical properties of binary system containing predominantly poorly compressible drug candidate. The predictions of these models and conclusions can be systematically generalized to other pharmaceutical powders.
Keywords: Compaction; Tensile strength; Binary mixtures; Percolation theory; Mechanical property;
Modelling, solubility and pK a of five sparingly soluble drugs by Urszula Domańska; Aneta Pobudkowska; Aleksandra Pelczarska; Łukasz Żukowski (115-122).
New thermophysical data, solubility data, and pK a values are presented for five drugs cimetidine, phenylbutazone, fenbufen, nitrofurantoin, triamterene, which will improve all prediction-methods and their precision.Drug solubility is an important aspect of drug development. The objective of this investigation was to measure solubilities of five drugs (cimetidine, phenylbutazone, fenbufen, nitrofurantoin, triamterene) at constant pH in range of temperature from 270 to 340 K in three solvents: water, ethanol and 1-octanol with the dynamic-visual method and the saturation shake-flask method using spectrophotometric analysis. The Barton group contribution method was used for the calculations of molar volumes of solutes. The thermodynamic description of the solubility curves was made using the thermophysical properties obtained with the differential scanning microcalorimetry technique (DSC). The DSC measurements have shown different than existing in the literature enthalpies of melting for phenylbutazone and fenbufen. The experimental solubility data also differ from the literature data, normally measured at one, or two temperatures only. The solubility data have been correlated by means of three commonly known excess Gibbs energy, G E equations. The activity coefficients of drugs at saturated solutions were calculated from the experimental data. Reexamination of the pK a values using diluted solutions was made with the Bates–Schwarzenbach method for the pK a measurements. The association constants and corresponding pK a values of drugs were close to the most of the literature data. We hope that our new solubility data, thermophysical data, and pK a values will improve all prediction-methods and their precision.
Keywords: Poorly soluble drug; Solubility; pK a; Modelling;
Deoxycholate hydrogels of betamethasone-17-valerate intended for topical use: In vitro and in vivo evaluation by Taner Şenyiğit; Işıl Tekmen; Ülker Sönmez; Patrizia Santi; Özgen Özer (123-129).
Na-DOC gels produced significantly higher flux and anti-inflammatory activity compared to commercial cream at all time intervals.The aim of this study was to evaluate the suitability of sodium-deoxycholate (Na-DOC) gels containing betamethasone-17-valerate (BMV) for topical application. The gels were characterized for rheological and textural properties. The in vitro flux of BMV from Na-DOC gels across rat skin was 2.5 (0.05% gel) and 8.5 times (0.1% gel) higher compared to the commercial cream (0.1%), respectively. The pharmacodynamic responses after in vivo topical application in rats were also determined. A significant correlation between anti-inflammatory activity and in vitro permeation of BMV was observed. Na-DOC gels produced significantly higher edema inhibition compared to commercial cream at all time intervals. Finally, according to the results of histology studies, Na-DOC gel has no irritant effect on the skin.In conclusion, Na-DOC gel formulation could be suggested as a promising alternative system for the topical application of BMV.
Keywords: Betamethasone valerate; Sodium-deoxycholate gel; Texture profile analysis; Skin permeation enhancement; Anti-inflammatory activity;
Antitumor efficacy of solid dispersion of paclitaxel prepared by supercritical antisolvent process in human mammary tumor xenografts by Srinivasan Shanmugam; Jae-Hyun Park; Sang-Cheol Chi; Chul Soon Yong; Han-Gon Choi; Jong Soo Woo (130-135).
Paclitaxel solid dispersion (PSD) prepared by supercritical antisolvent process was very effective and safe, without Cremophor-associated toxicities of Taxol®, in human mammary tumor xenografts with possibilities of dose escalation.The efficacy of intravenous chemotherapy for breast cancer has been improving with newer agents. However, the fractional improvements in breast cancer progression-free survival were quite modest and these small gains are obtained at the cost of significant toxicity. To address this problem, paclitaxel solid dispersion (PSD), a Cremophor EL-free formulation prepared by supercritical antisolvent process using hydrophilic polymers as carrier, was developed to avoid Cremophor EL-associated toxicities in Taxol®. In this study, we investigated the antitumor activity of PSD as a function of dose from 12 to 24 mg/kg (dose–effect) and compared antitumor activity of 18 mg/kg dose of PSD to that of Taxol® (relative efficacy) in female athymic mice bearing mammary tumor xenografts. In dose–effect study, PSD showed excellent activity and good tolerance at all doses tested with a significant increase in tumor growth inhibition, recurrence time, survival percent, and number of tumor free survivors compared to control (P < 0.01). In all of the four doses tested in this study, the magnitude of the increase in effectiveness of PSD was quite substantial and statistically significant with similar degrees of weight loss. In relative efficacy study of PSD and Taxol®, PSD demonstrated a greater degree of tumor growth inhibition with 10 complete tumor regressions (100%) and eight tumor-free survivors (80% cure). Besides, mice treated with PSD regained their initial body weight by day 27 following initial acute weight reductions, whereas mice treated with Taxol® required more than 40 days to regain their initial weight. In conclusion, PSD prepared by supercritical process was very effective and safe, without Cremophor EL-associated toxicities of Taxol®, in human mammary tumor xenografts with possibilities of dose escalation.
Keywords: Paclitaxel; Solid dispersion; Supercritical antisolvent process; Antitumor efficacy; Mammary tumor xenografts;
In vitro and in vivo antioxidant properties of chlorogenic acid and caffeic acid by Yuki Sato; Shirou Itagaki; Toshimitsu Kurokawa; Jiro Ogura; Masaki Kobayashi; Takeshi Hirano; Mitsuru Sugawara; Ken Iseki (136-138).
Dietary polyphenols are thought to be beneficial for human health as antioxidants. Coffee beans contain a common polyphenol, chlorogenic acid. Chlorogenic acid is the ester of caffeic acid and quinic acid. Although these polyphenols have received much attention, there is little evidence indicating a relationship between the effect and the rate of absorption. In this study, we focused on the beneficial effects of chlorogenic acid and caffeic acid, a major metabolite of chlorogenic acid. We carried out in vitro and in vivo experiments. In the in vitro study, caffeic acid had stronger antioxidant activity than that of chlorogenic acid. The uptake of chlorogenic acid by Caco-2 cells was much less than that of caffeic acid. The physiological importance of an orally administered compound depends on its availability for intestinal absorption and subsequent interaction with target tissues. We then used an intestinal ischemia–reperfusion model to evaluate antioxidant activities in vivo. We found that both chlorogenic acid and caffeic acid had effects on intestinal ischemia–reperfusion injury. Since caffeic acid has a stronger antioxidant activity than that of chlorogenic acid and chlorogenic acid is hydrolyzed into caffeic acid in the intestine, it is possible that caffeic acid plays a major role in the protective effect of chlorogenic acid against ischemia–reperfusion injury.
Keywords: Intestine; Antioxidant; Chlorogenic acid; Caffeic acid; Absorption; Ischemia–reperfusion;
Stimuli-responsive magnetic particles for biomedical applications by S.F. Medeiros; A.M. Santos; H. Fessi; A. Elaissari (139-161).
An ideal stimuli-responsive magnetic system possibilities the monitoring of the medication in the organism followed by the treatment using local drug delivery or hyperthermia.In recent years, magnetic nanoparticles have been studied due to their potential applications as magnetic carriers in biomedical area. These materials have been increasingly exploited as efficient delivery vectors, leading to opportunities of use as magnetic resonance imaging (MRI) agents, mediators of hyperthermia cancer treatment and in targeted therapies. Much attention has been also focused on “smart” polymers, which are able to respond to environmental changes, such as changes in the temperature and pH. In this context, this article reviews the state-of-the art in stimuli-responsive magnetic systems for biomedical applications. The paper describes different types of stimuli-sensitive systems, mainly temperature- and pH sensitive polymers, the combination of this characteristic with magnetic properties and, finally, it gives an account of their preparation methods. The article also discusses the main in vivo biomedical applications of such materials. A survey of the recent literature on various stimuli-responsive magnetic gels in biomedical applications is also included.
Keywords: Magnetic nanoparticles; Ferrofluid; Smart polymers; N-vinylcaprolactam; Biomedical; Applications;
Development of biodegradable porous starch foam for improving oral delivery of poorly water soluble drugs by Chao Wu; Zhongyan Wang; Zhuangzhi Zhi; Tongying Jiang; Jinghai Zhang; Siling Wang (162-169).
A biodegradable porous starch foam (BPSF) was developed for the first time as a carrier in order to improve the dissolution and enhance the oral bioavailability of lovastatin – defined as a model poorly water soluble BCS type II drug. In this paper, BPSF was prepared by the solvent exchange method and characterized by scanning electron microscopy (SEM) and nitrogen adsorption/desorption analysis in order to perform the morphological and structural characterization of BPSF. Lovastatin was loaded by immersion/solvent evaporation into the BPSF which provided a stable hydrophilic matrix with a nano-porous structure. The solid state properties of the loaded BPSF samples were characterized by SEM, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). In vitro and in vivo drug release studies showed that when BPSF was used as a carrier it allowed immediate release of lovastatin and enhanced the dissolution rate in comparison with crystalline lovastatin and commercial capsules. These results provide important information about the mechanism of drug adsorption and release from BPSF as a carrier. Accordingly, BPSF has a promising future as a device for the oral delivery of poorly water soluble drugs.
Keywords: Biodegradable porous starch foam (BPSF); Lovastatin; Bioavailability; Poorly water soluble drugs;
PET imaging of brain cancer with positron emitter-labeled liposomes by Naoto Oku; Mina Yamashita; Yurie Katayama; Takeo Urakami; Kentaro Hatanaka; Kosuke Shimizu; Tomohiro Asai; Hideo Tsukada; Shuji Akai; Hiroaki Kanazawa (170-177).
Since nanocarriers such as liposomes are known to accumulate in tumors of tumor-bearing animals, and those that have entrapped a positron emitter can be used to image a tumor by PET, we applied 18F-labeled 100-nm-sized liposomes for the imaging of brain tumors. Polyethylene glycol (PEG)-modified liposomes, which are known to accumulate in tumors by passive targeting and those modified with Ala-Pro-Arg-Pro-Gly, which are known to home into angiogenic sites were used. Those liposomes labeled with DiI fluorescence accumulated in a glioma implanted in a rat brain 1 h after the injection, although they did not accumulate in the normal brain tissues due to the protection afforded by the blood–brain barrier. Preformed liposomes were easily labeled with 1-[18F]fluoro-3,6-dioxatetracosane, and enabled the imaging of gliomas by PET with higher contrast than that obtained with [18F]deoxyfluoroglucose. In addition, the smallest tumor among those tested, having a diameter of 1 mm was successfully imaged by the liposomal 18F. Therefore, nanocarrier-based imaging of brain tumors is promising for the diagnosis of brain cancer and possible drug delivery-based therapy.
Keywords: Positron emission tomography; Brain cancer; Liposome; Cancer diagnosis; Passive targeting; Angiogenesis;
Angiotensin II-induced hypertension enhanced therapeutic efficacy of liposomal doxorubicin in tumor-bearing mice by Yoshiyuki Hattori; Haruya Ubukata; Kumi Kawano; Yoshie Maitani (178-184).
In this study, we investigated whether the therapeutic efficacy of liposomal doxorubicin (DXR-SL) could be enhanced by angiotensin II (AT)-induced hypertension. AT-induced hypertension increased the volume of tumor blood flow in mice bearing a poorly vascularized Lewis lung carcinoma (LLC) tumor, but only slightly in mice bearing a well-vascularized colon carcinoma Colon 26 (C26) tumor. In therapeutic efficacy, AT-induced hypertension enhanced the antitumor activity of DXR-SL in mice bearing LLC and C26 tumors. Localization of DXR-SL after injection by AT-induced hypertension was observed outside tumor blood vessels in LLC and C26 tumors, but within them under the normotension. From these findings, AT-induced hypertension had potential to improve the delivery of DXR-SL to both well- and poorly vascularized solid tumors.
Keywords: Angiotensin II; Induced hypertension chemotherapy; Liposome; Doxorubicin;
Nanostructured lipid carrier (NLC) coated with Chitosan Oligosaccharides and its potential use in ocular drug delivery system by Qiuhua Luo; Junming Zhao; Xiangrong Zhang; Weisan Pan (185-191).
Pre-corneal drainage of 99mTc-DTPA labeled formulations after topical instillation.The objective of the present investigation was to explore the potential of the Chitosan Oligosaccharides (COS)-coated NLC (nanostructured lipid carrier) for ocular drug delivery. NLC loaded with flurbiprofen was prepared by melt-ultrasonic method and then coated with COS with a molecular weight of 3000–6000 kDa. After coating, the particles reflected spherical morphology with smooth surface under transmission electron microscope (TEM) analysis and a changed zeta potential from −0.446 mV to +20.7 mV. The ocular bioadhesion property was evaluated by Gamma scintigraphic technique, revealing that the clearance of the formulations labeled with radioactive 99mTc-DTPA was significantly delayed in the presence of COS, and the AUC of the COS-coated formulation had a 7.7-fold increase comparing with non-coated ones. Additionally, enhanced transcorneal penetration was achieved by using the COS coating with a corresponding apparent permeability coefficients (P app) which had a 2.4-fold increase comparing with the reference. Consequently, COS coating modified the properties of NLCs and presented a series of notable advantages in ophthalmic application.
Keywords: Chitosan Oligosaccharides; Nanostructured lipid carrier; Ocular drug delivery; Gamma scintigraphy; Controlled-release; Corneal penetration;
Nano spray drying: A novel method for preparing protein nanoparticles for protein therapy by Sie Huey Lee; Desmond Heng; Wai Kiong Ng; Hak-Kim Chan; Reginald B.H. Tan (192-200).
There has been an increasing interest in the development of protein nanotherapeutics for diseases such as cancer, diabetes and asthma. Spray drying with prior micro mixing is commonly used to obtain these powders. However, the separation and collection of protein nanoparticles with conventional spray dryer setups has been known to be extremely challenging due to its typical low collection efficiency for fine particles less than 2 μm. To date, there has been no feasible approach to produce these protein nanoparticles in a single step and with high yield (>70%). In this study, we explored the feasibility of the novel Nano Spray Dryer B-90 (equipped with a vibrating mesh spray technology and an electrostatic particle collector) for the production of bovine serum albumin (BSA) nanoparticles. A statistical experimental design method (Taguchi method based on three levels, five variables L18 orthogonal array robust design) was implemented to study the effect of and optimize the experimental conditions of: (1) spray mesh size, (2) BSA solution concentration, (3) surfactant concentration, (4) drying air flow rate and (5) inlet temperature on: (1) size and (2) morphology (axial ratio). Particle size and morphology were predominantly influenced by the spray mesh size and surfactant concentration, respectively. The drying air flow rate and inlet temperature had minimal impact. Optimized production of smooth spherical nanoparticles (median size: 460 ± 10 nm, axial ratio: 1.03 ± 0.00, span 1.03 ± 0.03, yield: 72 ± 4%) was achieved using the 4 μm spray mesh at BSA concentration of 0.1% (w/v), surfactant concentration of 0.05% (w/v), drying flow rate of 150 L/min and inlet temperature of 120 °C. The Nano Spray Dryer B-90 thus offers a new, simple and alternative approach for the production of protein nanoparticles suited for a variety of drug delivery applications.
Keywords: Nano spray dryer; Protein therapy; Nanoparticles; Bovine serum albumin; Spray drying;
Antitumoral activity of camptothecin-loaded nanoparticles in 9L rat glioma model by Yasemin Çırpanlı; Emilie Allard; Catherine Passirani; Erem Bilensoy; Laurent Lemaire; Sema Çalış; Jean-Pierre Benoit (201-206).
In this study, camptothecin loaded nanoparticulate delivery systems were developed with either amphiphilic cyclodextrins, poly(lactide-co-glycolide) or poly-ɛ-caprolactone. All nanoparticles were prepared with nanoprecipitation technique.Camptothecin (CPT), a plant alkaloid, is a potent anticancer drug in cell culture studies but it is clinically inactive due to rapid hydrolysis under physiological conditions. The drug exists in two forms depending on the pH value, an active lactone form at pH below 5 and an inactive carboxylate form at basic pH and this is a reversible reaction. In this study, nanoparticulate delivery systems were developed with either amphiphilic cyclodextrins, poly(lactide-co-glycolide) or poly-ɛ-caprolactone in order to maintain the active lactone form and prevent the drug from hydrolysis. All nanoparticles were prepared with nanoprecipitation technique. Mean particle sizes were 130–280 nm and surface charges were negative. The encapsulation efficiency was significantly higher for amphiphilic cyclodextrin nanoparticles when compared to polymeric nanoparticles. Nanoparticle formulations based on cyclodextrins showed a controlled release profile extended up to 12 days. 6-O-Capro-β-cyclodextrin (1.44 μg/60 μL CPT) and concentrated 6-O-Capro-β-cyclodextrin (2.88 μg/60 μL CPT) nanoparticles significantly modified the growth or lethality of the 9L gliomas, since the median survival time was 26 days for the untreated group and between 27 and 33 days for amphiphilic cyclodextrin nanoparticle groups. These results indicate that, CPT-loaded amphiphilic cyclodextrin nanoparticles may provide a promising carrier system for the effective delivery of CPT in comparison to polymeric analogues.
Keywords: Camptothecin; Amphiphilic cyclodextrin; Poly(lactide-co-glycolide); Poly-ɛ-caprolactone; Nanoparticle; 9L glioma model;
Cellular uptake and degradation behaviour of biodegradable poly(ethylene glycol-graft-methyl methacrylate) nanoparticles crosslinked with dimethacryloyl hydroxylamine by Stefan Scheler; Martina Kitzan; Alfred Fahr (207-218).
Nanoparticles made of diacyl hydroxylamine-crosslinked PEGylated polymethacrylates differ from conventional biodegradable particles. They are hydrolyzable at pH ≥ 7 and their cellular uptake is strongly controlled by their surface charge.Crosslinked polymers with hydrolytically cleavable linkages are highly interesting materials for the design of biodegradable drug carriers. The aim of this study was to investigate if nanoparticles made of such polymers have the potential to be used also for intracellular drug delivery. PEGylated nanoparticles were prepared by copolymerization of methacrylic acid esters and N,O-dimethacryloylhydroxylamine (DMHA). The particles were stable at pH 5.0. At pH 7.4 and 9.0 the degradation covered a time span of about 14 days, following first-order kinetics with higher crosslinked particles degrading slower. Cellular particle uptake and cytotoxicity were tested with L929 mouse fibroblasts. The particle uptake rate was found to correlate linearly with the surface charge and to increase as the zeta potential becomes less negative. Coating of the particle surface with polysorbate 80 drops the internalization rate close to zero and the charge dependence disappears. This indicates the existence of a second effect apart from surface charge. A similar pattern of correlation with zeta potential and coating was also found for the degree of membrane damage while there was no effect of polysorbate on the cell metabolism which increased as the negative charge decreased. It is discussed whether exocytotic processes may explain this behaviour.
Keywords: Nanoparticle; Biodegradation; Cross-linking; Polyethylene oxide; Cell culture; Fibroblast;
Protective effect of Coenzyme Q10 against oxidative damage in human lens epithelial cells by novel ocular drug carriers by Siling Wang; Jing Zhang; Tongying Jiang; Li Zheng; Zhanyou Wang; Jinghai Zhang; Pan Yu (219-229).
With the enhanced permeation effect of the TMC coating, Coenzyme Q10-loaded TMC-coated liposomes appear to be a promising ophthalmic drug delivery carrier with an efficacy in protecting HLECs against H2O2-induced oxidative damage.The evaluation of N-trimethyl chitosan (TMC)-coated liposomes containing Coenzyme Q10 as potential ophthalmic drug delivery system was carried out. Firstly, transcorneal permeation studies were conducted at 34 °C using a side-by-side diffusion apparatus. The transport process of the fluorescent marker, rhodamine B, across the corneal epithelium was visualized with confocal laser scanning microscopy. Secondly, the human lens epithelial cells (HLECs) were cultured without or with Coenzyme Q10 followed by addition of H2O2. The cell viability and apoptosis were evaluated. The permeability coefficient for rhodamine B with TMC-coated liposomes increased more than two times in comparison with the value obtained for solution as control, from (0.42 ± 0.018) × 105 cm s−1 to (1.31 ± 0.030) × 105 cm s−1. Confocal laser scanning microscopy revealed that a TMC coating enhanced the transepithelial transport, dependent on the TMC concentration and contacting time. Coenzyme Q10 elevated the cell viability and reduced the oxidative damage with the decreased percentage of apoptotic cells in a positive concentration-dependent manner. The ATP content of liposome-treated cells was increased about 2-fold compared with that of H2O2-treated cells. Together, our findings demonstrate that with the enhanced permeation effect of the TMC coating, Coenzyme Q10-loaded TMC-coated liposomes appear to be a promising ophthalmic drug delivery carrier with an efficacy in protecting HLECs against H2O2-induced oxidative damage.
Keywords: N-trimethyl chitosan; Coenzyme Q10; Transcorneal permeation; Human lens epithelial cells; Anti-apoptosis;
Polyvalent catanionic vesicles: Exploring the drug delivery mechanisms by Ariane Boudier; Pauline Castagnos; Elodie Soussan; Grégory Beaune; Haouaria Belkhelfa; Christine Ménager; Valérie Cabuil; Laila Haddioui; Christine Roques; Isabelle Rico-Lattes; Muriel Blanzat (230-236).
Among drug delivery systems, catanionic vesicles now appear as powerful candidates for pharmaceutical applications because they are relatively cheap and easy to use, thus well corresponding to industrial requirements. Using labelled vesicles made of a tricatenar catanionic surfactant, the work reported here aims at exploring the mechanisms by which internalisation into a cell occurs. The study was performed on various cell types such as phagocytic as well as non-phagocytic cells using confocal laser scanning microscopy and flow cytometry. Using various inhibitors, endocytosis and also a passive process, as probably fusion, were highlighted as interaction phenomena between catanionic vesicles and cell membranes. Finally, the interaction modelled with giant liposomes as membrane models confirmed the hypothesis of the occurrence of a fusion phenomenon between the nanovectors and cell membranes. This process highlights the potential of catanionic vesicles for a future pharmaceutical application as a universal drug delivery system.
Keywords: Catanionic vesicles; Drug delivery; Phagocytic and non-phagocytic cells; Membrane fusion; Endocytosis; Internalisation modelisation;
Analysis of lipid nanoparticles by Cryo-EM for characterizing siRNA delivery vehicles by Randy Crawford; Belma Dogdas; Edward Keough; R. Matthew Haas; Wickliffe Wepukhulu; Steven Krotzer; Paul A. Burke; Laura Sepp-Lorenzino; Ansuman Bagchi; Bonnie J. Howell (237-244).
In this paper we describe a semiautomatic Cryo-Electron Microscopy image analysis framework to facilitate biophysical analysis of lipid nanoparticles carrying siRNA for in vivo therapeutics.Lipid nanoparticles are self-assembling, dynamic structures commonly used as carriers of siRNA, DNA, and small molecular therapeutics. Quantitative analysis of particle characteristics such as morphological features can be very informative as biophysical properties are known to influence biological activity, biodistribution, and toxicity. However, accurate characterization of particle attributes and population distributions is difficult. Cryo-Electron Microscopy (Cryo-EM) is a leading characterization method and can reveal diversity in particle size, shape and lamellarity, however, this approach is traditionally used for qualitative review or low throughput image analysis due to inherent EM micrograph contrast characteristics and artifacts in the images which limit extraction of quantitative feature values. In this paper we describe the development of a semiautomatic image analysis framework to facilitate reliable image enhancement, object segmentation, and quantification of nanoparticle attributes in Cryo-EM micrographs. We apply this approach to characterize two formulations of siRNA-loaded lipid nanoparticles composed of cationic lipid, cholesterol, and poly(ethylene glycol)-lipid, where the formulations differ only by input component ratios. We found Cryo-EM image analysis provided reliable size and morphology information as well as the detection of smaller particle populations that were not detected by standard dynamic light scattering (DLS) analysis.
Keywords: Drug delivery; Liposome characterization; Dynamic light scattering; Oligonucleotides; Nanodrugs; Imaging;
Entrapment and release difference resulting from hydrogen bonding interactions in niosome by Yong-Mei Hao; Ke’an Li (245-253).
The hydrogen bonding interaction between drugs and membrane molecules is discussed in detail and the corresponding quantitative analysis has been finished firstly. The results demonstrate that the hydrogen bonding interaction between drugs and membrane molecules is greatly helpful to improve the encapsulation efficiency of drugs and reduce the release rate.In this study the influence of hydrogen bonding interaction between niosomal membrane and solutes on the drug loading and release was investigated. Salicylic acid (SA) and p-hydroxyl benzoic acid (p-BA) were selected as models. Niosomes were prepared with 1:1 molar ratios of various surfactants and cholesterol by film hydration technique, and the corresponding formulation variables were optimized to achieve the maximum entrapment efficiencies (EE%). The EE% of different formulations followed the trend Span 60 > Span 40 > Span 20 > Span 80. Additionally, it was also found that the EE% of p-BA was much higher than that of SA. This difference may be due to the formation of hydrogen bond between p-BA and niosomal membrane, and the corresponding interaction diagram has been proposed and confirmed indirectly by UV spectroscopy method. The quantitative analysis of hydrogen binding interaction between solutes and niosome has been finished firstly, and the corresponding entrapment equilibrium constant K has been calculated as well. Moreover, in vitro the release of both drugs from niosomes was examined in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), respectively. The results indicated that the release of p-BA in SIF was much slower than that in SGF, and the release rate of SA in SGF is apparently slower than that in SIF. The possible mechanism was given as well.
Keywords: Niosome; Drug carrier; Hydrogen bonding interaction; Salicylic acid; p-Hydroxyl benzoic acid;
Development and characterization of site specific target sensitive liposomes for the delivery of thrombolytic agents by Bhuvaneshwar Vaidya; Manasa K. Nayak; Debabrata Dash; G.P. Agrawal; Suresh P. Vyas (254-261).
In recent times, search for potent and highly selective thrombolytic agents with minimal side effects has become a major area of research. The aim of the present study was to develop and characterize target sensitive (TS) liposomes encapsulating streptokinase, a thrombolytic agent. The developed TS liposomes were composed of dioleylphophatidyl ethanolamine (DOPE) and dipalmityl-c(RGDfK) (10:1 mol/mol). Dipalmityl-c(RGDfK) was synthesized using typical carbodiimide chemistry using palmitic acid and c(RGDfK), while lysine was used as a spacer. Liposomes were of 100–120 nm size. In vitro drug release study showed that nearly 40% drug of the entrapped drug was released in 12 h in the PBS (pH 7.4), however on incubation with activated platelet about 90% of drug was released within 45 min. The results suggested target sensitivity of the liposomes. Further, targeting potential was confirmed using fluorescent microscopy and flow cytometry. Clot lysis study revealed that TS liposomes could not only reduce the clot lysis time but also increase the extent of clot lysis as compared to non-liposomal streptokinase solution. In conclusion, the present liposomal formulation will target the thrombolytic agent to the activated platelets in the thrombus and hence will improve the therapeutic efficacy of the drug.
Keywords: Target sensitive liposomes; Thrombolytic agents; Streptokinase; Targeting; Thrombus;
pH-sensitive Eudragit nanoparticles for mucosal drug delivery by Jin-Wook Yoo; Namita Giri; Chi H. Lee (262-267).
Drug delivery via vaginal epithelium has suffered from lack of stability due to acidic and enzymatic environments. The biocompatible pH-sensitive nanoparticles composed of Eudragit S-100 (ES) were developed to protect loaded compounds from being degraded under the rigorous vaginal conditions and achieve their therapeutically effective concentrations in the mucosal epithelium. ES nanoparticles containing a model compound (sodium fluorescein (FNa) or nile red (NR)) were prepared by the modified quasi-emulsion solvent diffusion method. Loading efficiencies were found to be 26% and 71% for a hydrophilic and a hydrophobic compound, respectively. Both hydrophilic and hydrophobic model drugs remained stable in nanoparticles at acidic pH, whereas they are quickly released from nanoparticles upon exposure at physiological pH. The confocal study revealed that ES nanoparticles were taken up by vaginal cells, followed by pH-responsive drug release, with no cytotoxic activities. The pH-sensitive nanoparticles would be a promising carrier for the vaginal-specific delivery of various therapeutic drugs including microbicides and peptides/proteins.
Keywords: pH-sensitive nanoparticles; Eudragit; Intravaginal delivery;
In vitro and in vivo evaluation of anti-inflammatory agents using nanoengineered alginate carriers: Towards localized implant inflammation suppression by Rahul Dev Jayant; Michael J. McShane; Rohit Srivastava (268-275).
The aim of this research was to develop nanoengineered alginate microspheres for localized delivery of anti-inflammatory drugs (dexamethasone and diclofenac sodium) for implantable “Smart tattoo” glucose biosensor used for continuous glucose monitoring. The formulation was prepared and characterized for in vitro drug release from uncoated and polyelectrolyte-coated microparticles. Biocompatibility was then tested using L929 cell-line; pilot in vivo studies with Sprague–Dawley (SD) rat subjects were performed to test the suppression of inflammation and fibrosis associated with implantation and was analyzed using standard hematoxylin and eosin staining method. The drug-loaded microspheres were able to deliver the drug for 30 days at a controlled rate with zero-order kinetics. The layer-by-layer self-assembly technique was used to effectively limit the burst release of drug from the matrix. Cell culture studies prove that the material are not cytotoxic and showed acceptable >80% cell viability in all the tested samples. In vivo studies show that both drugs were successful in controlling the implant/tissue interface by suppressing inflammation at the implant site. It was clearly evident that the combined approach of drug loaded carriers along with implanted biosensor shows promise in improving sensor biocompatibility and functionality. Thus, suggesting potential application of alginate microspheres as “smart-tattoo” glucose sensors.
Keywords: Alginate; Microspheres; Controlled release; Anti-inflammatory drugs; Layer-by-layer (LbL);
Photochemical internalization for pDNA transfection: Evaluation of poly(d,l-lactide-co-glycolide) and poly(ethylenimine) nanoparticles by M. Gargouri; A. Sapin; B. Arıca-Yegin; J.L. Merlin; P. Becuwe; P. Maincent (276-284).
The main objective of this study was to prepare two types of nanoparticles with poly(d,l-lactide-co-glycolide) (PLGA) and polyethylenimine (PEI) polymers. Plasmid DNA (pDNA) was adsorbed either on PLGA/PEI nanoparticles, or as PEI/DNA complex onto the surface of PLGA nanoparticles. Both types of nanoparticles were prepared by the double emulsion method. The nanoparticles were characterized by their size, zeta potential and pDNA or PEI/DNA complex adsorption. The PEI/DNA complex adsorption was confirmed with ethidium bromide assay. pDNA adsorption onto PLGA/PEI nanoparticles (PLGA/PEI–DNA) was studied by electrophoresis on agarose gel. Cytotoxicity and transfection efficiency of both types of nanoparticle and PEI/DNA complexes formulations were studied in head and neck squamous carcinoma cell line (FaDu). To improve endosomal release, photochemical internalization (PCI) was used. The zeta potential increased when the PEI/DNA complex adsorbed onto PLGA nanoparticles (PLGA–PEI/DNA). Optimal pDNA adsorption efficiency was achieved for nitrogen/phosphorous ratio ≥ 20/1. In vitro transfection and cells viability on FaDu cells with or without PCI were found to be variable depending on the type and concentration of nanoparticles. The results showed that transfection efficiency for PLGA/PEI–DNA or PLGA–PEI/DNA nanoparticles ranged between 2 and 80%, respectively. PCI was found to slightly improve the transfection efficiency for all formulations.
Keywords: Gene delivery; Nanoparticles; Photochemical internalization; Poly(d,l-lactide-co-glycolide); Polyethylenimine;
Preparation and characterization of water-soluble albumin-bound curcumin nanoparticles with improved antitumor activity by Tae Hyung Kim; Hai Hua Jiang; Yu Seok Youn; Chan Woong Park; Kyung Kook Tak; Seulki Lee; Hyungjun Kim; Sangyong Jon; Xiaoyuan Chen; Kang Choon Lee (285-291).
Water-soluble curcumin (CCM)-loaded human serum albumin (HSA) nanoparticles (CCM-HSA-NPs) and its improved antitumor activity.Curcumin (CCM), a yellow natural polyphenol extracted from turmeric (Curcuma longa), has potent anti-cancer properties as has been demonstrated in various human cancer cells. However, the widespread clinical application of this efficient agent in cancer and other diseases has been limited by its poor aqueous solubility and bioavailability. In this study, we prepared novel CCM-loaded human serum albumin (HSA) nanoparticles (CCM-HSA-NPs) for intravenous administration using albumin bound technology. Field emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS) investigation confirmed a narrow size distribution in the 130–150 nm range. Furthermore, CCM-HSA-NPs showed much greater water solubility (300-fold) than free CCM, and on storage, the biological activity of CCM-HSA-NPs was preserved with negligible activity loss. In vivo distributions and vascular endothelial cells transport studies demonstrated the superiority of CCM-HSA-NPs over CCM. Amounts of CCM in tumors after treatment with CCM-HSA-NPs were about 14 times higher at 1 h after injection than that achieved by CCM. Furthermore, vascular endothelial cell binding of CCM increased 5.5-fold, and transport of CCM across a vascular endothelial cell monolayer by Transwell testing was 7.7-fold greater for CCM-HSA-NPs than CCM. Finally, in vivo antitumor tests revealed that CCM-HSA-NPs (10 or 20 mg/kg) had a greater therapeutic effect (50% or 66% tumor growth inhibition vs. PBS-treated controls) than CCM (18% inhibition vs. controls) in tumor xenograft HCT116 models without inducing toxicity. We attribute this potent antitumor activity of CCM-HSA-NPs to enhanced water solubility, increased accumulation in tumors, and an ability to traverse vascular endothelial cell.
Keywords: Curcumin; Solubility; Nanoparticle; Human serum albumin; Antitumor;
Self-assembly nanoparticles for the delivery of bisphosphonates into tumors by G. Salzano; M. Marra; M. Porru; S. Zappavigna; A. Abbruzzese; M.I. La Rotonda; C. Leonetti; M. Caraglia; G. De Rosa (292-297).
Bisphosphonates (BPs) are molecules able to induce apoptosis in several cancer cell lines. However, their short half-life and the rapid uptake and accumulation within bone, limit its use as antitumor agent for extra-skeletal malignancies. Here we proposed a new delivery system to avoid BP accumulation into the bone, thus improving extra-skeletal bioavailability. In this work, we used the zoledronic acid (ZOL), a third generation bisphosphonate, able to induce apoptosis at micromolar concentration. We developed ZOL-containing self-assembly PEGylated nanoparticles (NPs) based on ZOL complexes with calcium phosphate NPs (CaPZ NPs) and cationic liposomes. PEGylation was achieved by two different strategies. CaPZ NPs were covered with PEGylated liposomes (pre-PLCaPZ NPs); alternatively, CaPZ NPs were previously mixed with cationic liposomes and then PEGylated by post-insertion method (post-PLCaPZ NPs). The NPs were fully characterized in terms of mean diameter and size distribution, morphology, ZOL loading, antiproliferative effect on different cell lines. Pre-PLCaPZ NPs showed the best technological characteristics, with a narrow size distribution and a high ZOL loading. Moreover, on different cancer cell lines, these NPs enhanced the antiproliferative effect of ZOL. Finally, in an animal model of prostate cancer, a significant reduction of tumor growth was achieved with pre-PLCaPZ NPs, while the tumor was unaffected by ZOL in solution.
Keywords: Zoledronic acid; Self-assembly nanoparticles; Calcium phosphate; Cationic liposomes;