DDSolver: an add-in program for modeling and comparison of drug dissolution profiles

Polyester-based microdisc systems for sustained release of neuroprotective phosphine-borane complexes

Phosphine-borane complexes are recently developed redox-active drugs that are neuroprotective in models of optic nerve injury and radioprotective in endothelial cells. However, a single dose of these compounds is short-lived, necessitating the development of sustained-release formulations of these novel molecules. We screened a library of biodegradable co- and non-block polyester polymer systems for release of incorporated phosphine-borane complexes to evaluate them as drug delivery systems for use in chronic disease. Bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) was combined with biodegradable polymers based on poly(D,L-lactide) (PDLLA), poly(L-lactide) (PLLA), poly(caprolactone) (PCL), poly(lactide-co-glycide) (PLGA), or poly(dioxanone-co-caprolactone) (PDOCL) to make polymer microdiscs, and release over time quantified. Of 22 polymer-PB1 formulations tested, 17 formed rigid polymers. Rates of release differed significantly based on the chemical structure of the polymer. PB1 released from PLGA microdiscs released most slowly, with the most linear release in polymers of 60:40 LA:GA, acid endcap, Mn 15 000-25 000 and 75:25 LA:GA, acid endcap, Mn 45 000-55 000. Biodegradable polymer systems can, therefore, be used to produce sustained-release formulations for redox-active phosphine-borane complexes, with PLGA-based systems most suitable for very slow release. The sustained release could enable translation to a clinical neuroprotective strategy for chronic diseases such as glaucoma.

Spray-Dried Thiolated Chitosan-Coated Sodium Alginate Multilayer Microparticles for Vaginal HIV Microbicide Delivery

It is hypothesized that novel thiolated chitosan-coated multilayer microparticles (MPs) with enhanced drug loading are more mucoadhesive than uncoated MPs and safe in vivo for vaginal delivery of topical anti-HIV microbicide. Formulation optimization is achieved through a custom experimental design and the alginate (AG) MPs cores are prepared using the spray drying method. The optimal MPs are then coated with the thiolated chitosan (TCS) using a layer-by-layer method. The morphological analysis, in situ drug payload, in vitro drug release profile, and mucoadhesion potential of the MPs are carried out using scanning electron microscopy, solid-state ³¹P NMR spectroscopy, UV spectroscopy, fluorescence imaging and periodic acid Schiff method, respectively. The cytotoxicity and preclinical safety of MPs are assessed on human vaginal (VK2/E6E7) and endocervical (End1/E6E7) epithelial cell lines and in female C57BL/6 mice, respectively. The results show that the MPs are successfully formulated with an average diameter ranging from 2 to 3 μm with a drug loading of 7-12% w/w. The drug release profile of these MPs primarily follows the Baker-Lonsdale and Korsmeyer-Peppas models. The MPs exhibit high mucoadhesion (20-50 folds) compared to native AGMPs. The multilayer MPs are noncytotoxic. Histological and immunochemical analysis of the mice genital tract shows neither signs of damage nor inflammatory cell infiltrate. These data highlight the potential use of TCS-coated AG-based multilayer MPs templates for the topical vaginal delivery of anti-HIV/AIDS microbicides.

Research Article. Kinetics and Mechanism of Drug Release from Loratadine Orodispersible Tablets Developed without Lactose

Objective: The aim of this study is to develop lactose-free orodispersible tablets with loratadine for patients with lactose intolerance. Materials and methods: Seven compositions (F1-F7) of 10 mg loratadine were prepared in form of orally disintegrating tablets, by direct compression, using croscarmellose sodium and pre-gelatinized starch in various concentrations as superdisintegrants, diluted with microcrystalline cellulose and combined with mannitol and maltodextrin as binder agents. The tablets had been studied in terms of their pharmacotechnical characteristics, by determining: the weight uniformity of the tablets, their friability, breaking strength and disintegration time, drug content and the dissolution profile of loratadine. The statistical analyses were performed with GraphPad Prism Software Inc. As dependent variables, both the hardness of the tablets and their disintegration ability differ between batches due to their compositional differences (as independent variables). DDSolver were used for modeling the kinetic of the dissolution processes by fitting the dissolution profiles with time-dependent equations (Zero-order, First-order, Higuchi, Korsmeyer-Peppas, Peppas-Sahlin). Results: All proposed formulas shows rapid disintegration, in less than 15 seconds, and the dissolution loratadine spans a period of about 10 minutes. Akaike index as well as R2 adjusted parameter have demonstrated that the studied dissolution profiles are the best fitted by Zero-order kinetic. Conclusion: In conclusion, association of croscarmellose sodium (7.5%) with pre-gelatinized starch (6%) as superdisintegrants and mannitol as the binder agent (35%), positively influences the dissolution properties of loratadine from orally fast dispersible tablets.

Real-Time Analysis of Tenofovir Release Kinetics Using Quantitative Phosphorus (31P) Nuclear Magnetic Resonance Spectroscopy

The dialysis method is classically used for drug separation before analysis, but does not provide direct and real-time drug quantification and has limitations affecting the dialysis rate. In this study, a phosphorus nuclear magnetic resonance (³¹P-qNMR) method is developed for the real-time quantification of therapeutic molecules in vitro. The release kinetics of model drug, tenofovir (anti-HIV microbicide), was analyzed in vaginal fluid simulant (VFS), seminal fluid simulant (SFS), and human plasma (HP) from chitosan nanofibers (size ∼100-200 nm) using the NMR (direct) method and compared with dialysis/UV-Vis (indirect) method. The assay was linear in VFS/SFS (0.20-5.0 mM), HP (0.30-5.0 mM of drug concentration range) and specific no drug ³¹P-qNMR chemical shift [∼15 ppm] interference with formulation/media components. Limit of detection values were 0.075/0.10/0.20 mM, whereas limit of quantification values were 0.20/0.20/0.30 mM in VFS/SFS/HP, respectively. The method was robust, precise (%RSE <2%), and accurate (%mean recovery 90%-110%). After 12 h, ∼77%/72%/70% wt/wt of tenofovir release was observed with direct, compared to ∼47%/52%/52% wt/wt by indirect method in VFS/SFS/HP, respectively. Approximately 20% decrease in %drug release observed with dialysis method suggested an interference with drug transport process due to the dialysis membrane and the Gibbs-Donnan effect. Overall, ³¹P-qNMR provides more accurate, real-time, and direct drug quantification for effective in vitro-in vivo correlation.

Justification of disintegration testing beyond current FDA criteria using in vitro and in silico models

Drug product performance testing is an important part of quality-by-design approaches, but this process often lacks the underlying mechanistic understanding of the complex interactions between the disintegration and dissolution processes involved. Whereas a recent draft guideline by the US Food and Drug Administration (FDA) has allowed the replacement of dissolution testing with disintegration testing, the mentioned criteria are not globally accepted. This study provides scientific justification for using disintegration testing rather than dissolution testing as a quality control method for certain immediate release (IR) formulations. A mechanistic approach, which is beyond the current FDA criteria, is presented. Dissolution testing via United States Pharmacopeial Convention Apparatus II at various paddle speeds was performed for immediate and extended release formulations of metronidazole. Dissolution profile fitting via DDSolver and dissolution profile predictions via DDDPlus™ were performed. The results showed that Fickian diffusion and drug particle properties (DPP) were responsible for the dissolution of the IR tablets, and that formulation factors (eg, coning) impacted dissolution only at lower rotation speeds. Dissolution was completely formulation controlled if extended release tablets were tested and DPP were not important. To demonstrate that disintegration is the most important dosage form attribute when dissolution is DPP controlled, disintegration, intrinsic dissolution and dissolution testing were performed in conventional and disintegration impacting media (DIM). Tablet disintegration was affected by DIM and model fitting to the Korsmeyer-Peppas equation showed a growing effect of the formulation in DIM. DDDPlus was able to predict tablet dissolution and the intrinsic dissolution profiles in conventional media and DIM. The study showed that disintegration has to occur before DPP-dependent dissolution can happen. The study suggests that disintegration can be used as performance test of rapidly disintegrating tablets beyond the FDA criteria. The scientific criteria and justification is that dissolution has to be DPP dependent, originated from active pharmaceutical ingredient characteristics and formulations factors have to be negligible.

Formulation, release characteristics, and bioavailability study of gastroretentive floating matrix tablet and floating raft system of Mebeverine HCl

To prolong the residence time of dosage forms within the gastrointestinal tract until all drug is released at the desired rate is one of the real challenges for oral controlled-release drug delivery systems. This study was designed to develop a controlled-release floating matrix tablet and floating raft system of Mebeverine HCl (MbH) and evaluate different excipients for their floating behavior and in vitro controlled-release profiles. Oral pharmacokinetics of the optimum matrix tablet, raft system formula, and marketed Duspatalin^® 200 mg retard as reference were studied in beagle dogs. The optimized tablet formula (FT-10) and raft system formula (FRS-11) were found to float within 34±5 sec and 15±7 sec, respectively, and both remain buoyant over a period of 12 h in simulated gastric fluid. FT-10 (Compritol/HPMC K100M 1:1) showed the slowest drug release among all prepared tablet formulations, releasing about 80.2% of MbH over 8 h. In contrast, FRS-11 (Sodium alginate 3%/HPMC K100M 1%/Precirol 2%) had the greatest retardation, providing sustained release of 82.1% within 8 h. Compared with the marketed MbH product, the C_max of FT-10 was almost the same, while FRS-11 maximum concentration was higher. The t_max was 3.33, 2.167, and 3.0 h for marketed MbH product, FT-10, and FRS-11, respectively. In addition, the oral bioavailability experiment showed that the relative bioavailability of the MbH was 104.76 and 116.01% after oral administration of FT-10 and FRS-11, respectively, compared to marketed product. These results demonstrated that both controlled-released floating matrix tablet and raft system would be promising gastroretentive delivery systems for prolonging drug action.

Dehydroascorbate-derivatized chitosan particles for targeting antimalarial agents to infected erythrocytes

The mammalian glucose transporter GLUT-1 and Plasmodium falciparum hexose transporter PfHT1 are overexpressed on human RBC infected with the parasite (iRBC), presumably for enhanced glucose uptake. Dehydroascorbic acid (DHA) competes out glucose in GLUT-1 binding. We prepared particles containing chloroquine phosphate using novel derivatives of chitosan (CSN). CSN was either pre-derivatized with DHA (PRE) or particles made of CSN were derivatized by surface-grafting DHA (POST). The optimized formulations were analyzed for size (170-200nm) drug content (about 40%) entrapment efficiency (50-57%), in vitro drug release (80% in 72h, Higuchi's model), hemolysis on exposure to whole blood or RBC at 5% hematocrit, cytotoxicity towards cultured HEK 293T (kidney) and HepG2 (hepatic) cells, targeting iRBC and in vitro efficacy against P. falciparum. PRE particles were superior to POST CSN particles in terms of uptake and extent of preferential targeting to iRBCs than RBCs. Unlike starch particles reported earlier, dextrose did not competitively inhibit uptake of DHA-derivatized CSN particles. Both formulations significantly induced parasite inhibition at 1nM while free drug showed comparable activity at 100nM. Both PRE and POST particles were superior to free drug in efficacy. Targeting with high efficiency promises dose reduction and possibility of overcoming efflux-based drug resistance.

In vitro antiherpes effect of C-glycosyl flavonoid enriched fraction of Cecropia glaziovii encapsulated in PLGA nanoparticles

In this work is reported a novel and promising approach for the preparation of C-glycosylflavonoid enriched fraction of Cecropia glaziovii (EFF-Cg) loaded PLGA nanoparticles (NP) with antiherpes properties. The purpose of this study was to evaluate and to compare the effect of two nonionic surfactants (poloxamer 188 (PLU) and polyvinyl alcohol (PVA)), and also an emulsion stabilized by solid particles of cellulose nanocrystal (CNC) in place of surfactants. The characterization of these nanoparticles was in terms of size, polydispersity index, zeta potential, morphology, thermogravimetric analysis (TGA), loading capacity and percent yield. Since TGA analysis revealed thermo stability especially for NP-PLU, this formulation was selected for the evaluation of drug release profile, cytotoxicity and antiherpes activity. The drug delivery profile demonstrated a sustained release through the polymer structure and a significant reduction of the polymer molecular weight at 21-day period. The cytotoxicity of these nanoparticles was determined on Vero cells, and the selected formulation did not exhibit cytotoxicity even at the highest tested concentration. The results demonstrated a potential antiherpetic effect of the EFF-Cg loaded NP at 48h of testing. In summary, EFF-Cg loaded NP exhibited a promising system for the effective drug delivery in the treatment of herpes infections.

Influence of Lipid Composition, pH, and Temperature on Physicochemical Properties of Liposomes with Curcumin as Model Drug

The physicochemical properties of large unilamellar vesicles (LUVs) were assessed with respect to lipid composition, pH, time, and temperature by monitoring their size, zeta potential, drug payload, and thermal behavior. A conventional thin film hydration technique was employed to prepare liposomes from soy phosphatidylcholine (SPC), dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG), and a 7:3 (M/M) mixture of DPPC+DPPG along with 30 mole% cholesterol in each combination. While the size of liposomes depended on lipid composition, pH and temperature, the zeta potential was found to be independent of the pH of the medium, although it varied with liposome type. Spherical morphology and bilayer were observed by electron microscopy. The phase transition temperature increased with decreasing pH. Membrane micro-viscosity showed the highest value for SPC, and membrane rigidity increased with increasing pH. The entrapment efficiency of liposomes with reference to curcumin was as follows: DPPC>DPPC+DPPG>DPPG>SPC. Sustained release of curcumin was observed for all liposomes. Curcumin-loaded liposomes exhibited substantial antibacterial activity against the gram-positive bacteria Bacillus amyloliquefaciens. Additional studies are needed to improve the understanding of the effect of formulation variables on the physicochemical stability of liposomes.

Mechanistic insights into acyclovir-polyethylene glycol 20000 binary dispersions

Objective:

The objective of this study is to provide a mechanistic insight into solubility enhancement and dissolution of acyclovir (ACY) by polyethylene glycol20000 (PEG20000).

Materials and Methods:

Solid dispersions with differing ratios of drug (ACY) and carrier (PEG20000) were prepared and evaluated by phase solubility, in vitro release studies, kinetic analysis, in situ perfusion, and in vitro permeation studies. Solid state characterization was also done by Powder X-Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectroscopy (FT-IR) analysis and surface morphology was assessed by Polarizing Microscopic Image (PMI) analysis, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Nuclear Magnetic Resonance (NMR) analysis.

Results:

Thermodynamic parameters proved the solubilization effect of carrier. The aqueous solubility and dissolution of ACY were increased in all samples. Formation of solid solution, crystallinity reduction, and absence of interaction between drug and carrier was proved by XRD, DSC, and FTIR analysis. The particle size reduction and change in surface morphology were confirmed by SEM and AFM and analysis. The permeation coefficient and amount of drug diffused was higher in samples as compared to ACY. The stability was high in dispersions, and it was proved by NMR analysis.

Conclusion:

The mechanical insights into the enhancement of solubility and dissolution could be used as a platform to improve the aqueous solubility for other poor water soluble drugs.

The use of a freeze-dried extract of Ligusticum mutellina in a cosmetic cream with potential antioxidant properties

The aim of this work was to develop a cream formulation with potential antioxidant properties. Herein, a freeze-dried extract of Ligusticum mutellina was used as a source of active compounds. The proposed qualitative composition of the cream was characterized by a good polyphenolic compounds release profile. Of note, the highest R2adj values were obtained for the Korsmeyer-Peppas and Higuchi models (0.9159 and 0.9226, respectively). These results indicate that a freeze-dried extract of L. mutellina, due to its retained high phenolic acids content, could become a key component in antioxidant creams.

Stimuli-sensitive thiolated hyaluronic acid based nanofibers: synthesis, preclinical safety and in vitro anti-HIV activity

AIM

To develop a seminal enzyme bioresponsive, mucoadhesive nanofibers (NFs) as safe and effective nanocarriers for the prevention of HIV vaginal transmission.

METHODS

A novel thiolated hyaluronic acid (HA-SH) polymer was synthesized to fabricate tenofovir (TFV)-loaded electrospun NFs (HA-SH-NFs) and characterized in vitro/in vivo.

RESULTS

A triggered drug release (87% w/w) from the engineered HA-SH-NFs (mean diameter ∼75 nm) occured within 1 h under the influence of seminal hyaluronidase enzyme. HA-SH-NFs were noncytotoxic, induced no damage on the C57BL/6 mice genital-tract and other organs. No significant CD45 cell-infiltration and changes in cytokines level in cervicovaginal tissues were observed. HA-SH-NFs significantly enhanced both TFV retention and bioavailability in vaginal tissue compared with the 1% TFV-gel. The anti-HIV activity of TFV (on pseudotyped virus followed by luciferase assay) was not adversely affected by the electrospinning process.

CONCLUSION

HA-SH-NFs developed in this study could potentially serve as a safe nanotemplate for topical intravaginal delivery of HIV/AIDS microbicides.

Tenofovir Containing Thiolated Chitosan Core/Shell Nanofibers: In Vitro and in Vivo Evaluations

It is hypothesized that thiolated chitosan (TCS) core/shell nanofibers (NFs) can enhance the drug loading of tenofovir, a model low molecular weight and highly water-soluble drug molecule, and improve its mucoadhesivity and in vivo safety. To test this hypothesis, poly(ethylene oxide) (PEO) core with TCS and polylactic acid (PLA) shell NFs are fabricated by a coaxial electrospinning technique. The morphology, drug loading, drug release profiles, cytotoxicity and mucoadhesion of the NFs are analyzed using scanning and transmission electron microscopies, liquid chromatography, cytotoxicity assays on VK2/E6E7 and End1/E6E7 cell lines and Lactobacilli crispatus, fluorescence imaging and periodic acid colorimetric method, respectively. In vivo safety studies are performed in C57BL/6 mice followed by H&E and immunohistochemical (CD45) staining analysis of genital tract. The mean diameters of PEO, PEO/TCS, and PEO/TCS-PLA NFs are 118.56, 9.95, and 99.53 nm, respectively. The NFs exhibit smooth surface. The drug loading (13%-25%, w/w) increased by 10-fold compared to a nanoparticle formulation due to the application of the electrospinning technique. The NFs are noncytotoxic at the concentration of 1 mg/mL. The PEO/TCS-PLA core/shell NFs mostly exhibit a release kinetic following Weibull model (r² = 0.9914), indicating the drug release from a matrix system. The core/shell NFs are 40-60-fold more bioadhesive than the pure PEO based NFs. The NFs are nontoxic and noninflammatory in vivo after daily treatment for up to 7 days. Owing to their enhanced drug loading and preliminary safety profile, the TCS core/shell NFs are promising candidates for the topical delivery of HIV/AIDS microbicides such as tenofovir.

IN VITRO RELEASE KINETICS MODEL FITTING OF LIPOSOMES: AN INSIGHT

Liposomes are emerging cargoes for bioactive delivery owing to their widely accepted biocompatible and biodegradable nature. It is always a challenge to control the release of payload for effective delivery to the site of interest. Over the couple of decennia, mathematical modeling of release process is a need of time whether the drug remains in the circulation or reaches at the target site. For establishing a better in vitro - in vivo correlation, release kinetics models viz. Peppas, Higuchi, Weibull, Zero Order and First order including mechanistic models like All-or-None, Toroidal, and Biomembrane models etc. are continuously exploited to predict drug release profile. Most of these models rely on the diffusion equations based on the composition of liposomes and conditions of release. Here, we summarized the crucial reports exploring these models and associated interventions to know the underlying physicochemical release phenomenon. Such mathematical model fitting can be a promising approach to deduce release/delivery process to help in designing the safe and efficacious ("Smart") liposomes.

Lx2-32c-loaded polymeric micelles with small size for intravenous drug delivery and their inhibitory effect on tumor growth and metastasis in clinically associated 4T1 murine breast cancer

Lx2-32c is a novel taxane derivative with a strong antitumor activity. In this study, we developed Lx2-32c–loaded polymeric micelles (Lx2-32c-PMs) with small size and investigated their antitumor efficacy against tumor growth and metastasis on 4T1 murine breast cancer cell line with Cremophor EL–based Lx2-32c solution as the control. In this study, copolymer monomethoxy polyethylene glycol₂₀₀₀–polylactide₁₃₀₀ was used to prepare Lx2-32c-PMs by film hydration method, and their physicochemical properties were characterized as well, according to morphology, particle size, zeta potential, in vitro drug release, and reconstitution stability. Under confocal laser scanning microscopy, it was observed that Lx2-32c-PMs could be effectively taken up by 4T1 cells in a time-dependent manner. Cell Counting Kit-8 assay showed that the IC₅₀ of Lx2-32c-PMs was 0.3827 nM. Meanwhile, Lx2-32c-PMs had better ability to promote apoptosis and induce G₂/M cycle block and polyploidy formation, compared with Lx2-32c solution. More importantly, in vivo animal studies showed that compared to Lx2-32c solution, Lx2-32c-PMs possessed better ability not only to effectively inhibit the tumor growth, but also to significantly suppress spontaneous and postoperative metastasis to distant organs in 4T1 orthotopic tumor-bearing mice. Consequently, Lx2-32c-PMs have significantly prolonged the survival lifetime of tumor-bearing mice. Thus, our study reveals that Lx2-32c-PMs had favorable antitumor activity and exhibited a good prospect for application in the field of antitumor therapy.

Influence of barium sulfate X-ray imaging contrast material on properties of floating drug delivery tablets

The objective of the study was to reveal the influence of necessarily added barium sulfate (BaSO₄) X-ray contrast material on floating drug delivery tablets. Based on literature survey, a chosen floating tablet composition was determined containing HPMC and carbopol 943P as matrix polymers. One-factor factorial design with five levels was created for evaluation of BaSO₄ (X₁) effects on experimental parameters of tablets including: floating lag time, total floating time, swelling-, erosion-, dissolution-, release kinetics parameters and X-ray detected volume changes of tablets. Applied concentrations of BaSO₄ were between 0 and 20.0% resulting in remarkable alteration of experimental parameters related especially to flotation. Drastic deterioration of floating lag time and total floating time could be observed above 15.0% BaSO₄. Furthermore, BaSO₄ showed to increase the integrity of tablet matrix by reducing eroding properties. A novel evaluation of dissolutions from floating drug delivery systems was introduced, which could assess the quantity of drug dissolved from dosage form in floating state. In the cases of tablets containing 20.0% BaSO₄, only the 40% of total API amount could be dissolved in floating state. In vitro fine resolution X-ray CT imagings were performed to study the volume change and the voxel distributions as a function of HU attenuations by histogram analysis of the images. X-ray detected relative volume change results did not show significant difference between samples. After 24h, all tablets containing BaSO₄ could be segmented, which highlighted the fact that enough BaSO₄ remained in the tablets for their identification.

Enhanced tumor delivery and antitumor response of doxorubicin-loaded albumin nanoparticles formulated based on a Schiff base

A novel method was developed here to prepare albumin-based nanoparticles (NPs) for improving the therapeutic and safety profiles of chemotherapeutic agents. This approach involved crosslinking bovine serum albumin (BSA) using a Schiff base-containing vanillin, into NPs and loading doxorubicin (DOX) into the NPs by incubation. The resultant NPs (DOX-BSA-V-NPs) displayed a particle size of 100.5±1.3 nm with a zeta potential of -23.05±1.45 mV and also showed high drug-loading efficiency and excellent stability with respect to storage and temperature. The encapsulation of DOX into the BSA-V-NPs was confirmed by dynamic scanning calorimetry and Raman spectroscopy. DOX-BSA-V-NPs exhibited a significantly faster DOX release at pH 6.5 than pH 7.4, as well as in a solution with a higher glutathione concentration. In vitro studies showed that the cellular uptake of DOX-BSA-V-NPs was time-dependent, concentration-dependent, and faster than free DOX, while the cytotoxicity of DOX-BSA-V-NPs (IC50 value of 3.693 μg/mL) was superior to free DOX (IC50 value of 4.007 μg/mL). More importantly, DOX-BSA-V-NPs showed a longer mean survival time of 24.83 days, a higher tumor inhibition rate of 56.66%, and a decreased distribution in the heart than other DOX formulations in animal studies using a tumor xenograft model. Thus, the vanillin-based albumin NPs were shown here to be a promising carrier for tumor-targeted delivery of chemotherapeutic agents and, thus, should be further studied.

Towards the development of multifunctional chitosan-based iron oxide nanoparticles: Optimization and modelling of doxorubicin release

In the present work composite nanoparticles with a magnetic core and a chitosan-based shell were produced as drug delivery systems for doxorubicin (DOX). The results show that composite nanoparticles with a hydrodynamic diameter within the nanometric range are able to encapsulate more DOX than polymeric nanoparticles alone corresponding also to a higher drug release. Moreover the synthesis method of the iron oxide nanoparticles influences the total amount of DOX released and a high content of iron oxide nanoparticles inhibits DOX release. The modelling of the experimental results revealed a release mechanism dominated by Fickian diffusion.

Enhancement of the aqueous solubility and permeability of a poorly water soluble drug ritonavir via lyophilized milk-based solid dispersions

In the present study, a lyophilized milk-based solid dispersion (SD) of ritonavir (RTV) was developed with the goal of improving its aqueous solubility. The SD was prepared by lyophilization, and characterized for its physicochemical and functional properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photomicroscopy and powder X-ray diffraction (PXRD) were used to confirm the formation and robustness of the SD formulation. The prepared SD formulations were functionally evaluated by saturation solubility, in vitro drug release and ex vivo permeation studies. The optimized SD formulation exhibited a significantly higher (30-fold) aqueous solubility (11.36 ± 0.06 μg/mL), compared to the pure RTV (0.37 ± 0.03 μg/mL). The in vitro dissolution studies revealed a significantly higher (∼10-fold) efficiency of the optimized SD formulation in releasing the RTV, compared to the pure RTV. The ex vivo permeation studies with the everted intestine method showed that prepared SD formulation significantly improved the permeation of RTV (75.6 ± 3.09, % w/w), compared to pure RTV (20.45 ± 1.68, % w/w). Thus, SD formulation utilizing lyophilized milk as a carrier appears to be a promising alternative strategy to improve the aqueous solubility of poorly water soluble drugs.

Ethyl cellulose nanoparticles as a platform to decrease ulcerogenic potential of piroxicam: formulation and in vitro/in vivo evaluation

Nanoparticles (NPs) have long gained significant interest for their use in various drug formulations in order to increase bioavailability, prolong drug release, and decrease side effects of highly toxic drugs. The objective of this investigation was to evaluate the potential of ethyl cellulose-based NPs (EC-NPs) to modulate the release and reduce ulcerogenicity of piroxicam (PX) after oral administration. PX-loaded EC-NPs were prepared by solvent evaporation technique using different stabilizers at three concentration levels. Morphological examination of selected formulas confirmed the formation of spherical NPs with slightly porous surface. Formulation containing poloxamer-stabilized EC-NPs (P188/0.2), having a particle size of 240.26±29.24 nm, polydispersity index of 0.562±0.030, entrapment efficiency of 85.29%±1.57%, and modulated release of PX (88% after 12 hours), was selected as the optimum formulation. Differential scanning calorimetry demonstrated the presence of PX in an amorphous form in the NPs. Fourier-transform infrared spectroscopy revealed the possible formation of hydrogen bond and the absence of chemical interaction. In vivo study, evaluation of pharmacokinetic parameters, evaluation of gastric irritation potential, and histological examination were conducted after administration of the selected formulation. Time to reach maximum plasma concentration, t_max, of poloxamer-stabilized EC-NPs was significantly higher than that of Feldene^® 20 mg capsules (P≤0.001). Encapsulation of the acidic, gastric offender PX into NPs managed to significantly suppress gastric ulceration potential in rats (P≤0.05) as compared to that of PX suspension. A reduction of 66% in mean ulcer index was observed. In conclusion, poloxamer-stabilized EC-NPs (P188/0.2) had a significant potential of offsetting deleterious side effects common in PX use.

Design and evaluation of lipoprotein resembling curcumin-encapsulated protein-free nanostructured lipid carrier for brain targeting

Many nanoparticle matrixes have been demonstrated to be efficient in brain targeting, but there are still certain limitations for them. To overcome the shortcomings of the existing nanoparticulate systems for brain-targeted delivery, a lipoprotein resembling protein-free nanostructured lipid carrier (PS80-NLC) loaded with curcumin was constructed and assessed for in vitro and in vivo performance. Firstly, single factor at a time approach was employed to investigate the effects of various formulation factors. Mean particle sizes of ≤100nm, high entrapment efficiency (EE, about 95%) and drug loading (DL, >3%) were obtained for the optimized formulations. In vitro release studies in the presence of plasma indicated stability of the formulation under physiological condition. Compared with NLC, PS80-NLC showed noticeably higher affinity for bEnd.3 cells (1.56 folds greater than NLC) but with lower uptake in macrophages. The brain coronal sections showed strong and widely distributed fluorescence intensity of PS80-NLC than that of NLC in the cortex. Ex vivo imaging studies further confirmed that PS80-NLC could effectively permeate BBB and preferentially accumulate in the brain (2.38 times greater than NLC). The considerable in vitro and in vivo performance of the safe and biocompatible PS80-NLC makes it a suitable option for further investigations in brain targeted drug delivery.

Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets

The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation.

Immune response to antituberculosis drug-loaded gelatin and polyisobutyl-cyanoacrylate nanoparticles in macrophages

Aim: Secondary toxicity of nanoparticles (NPs) in macrophages is a well-known phenomenon. The aim of the study was to investigate the immuneresponse of macrophages after NP treatment. Methods & results: Antituberculosis drugs moxifloxacin and rifampicin were loaded into gelatin and polyisobutyl-cyanoacrylate NPs. The NPs were physicochemical characterized. Cellular immuneresponses and cellular viability were determined. The drug release kinetics vary depending on the type of NP, size and loading capacity. IC50 values of polyisobutyl-cyanoacrylate NPs were lower than for gelatin NPs. NPs treatment induced higher release of Th1 type cytokines compared with free drug. Conclusion: NPs together with chemotherapeutic drugs might be able to trigger an immune response in macrophages. The combined effect might be able to overcome mycobacteria infections.