Glibenclamide nanosuspension inhaler: development, in vitro and in vivo assessment.

Objective: The development of nanosuspension for targeted delivery of glibenclamide as hypoglycemic agent to the lung in an inhaler dosage form.Method: Glibenclamide nanosuspension formulations were prepared using Box-Behnken design to investigate the effect of independent factors on the dependent variables, Fourier-transform Infrared spectroscopy, Differential Scanning Calorimetry, evaluation of glibenclamide nanosuspension inhaler and in vivo hypoglycemic efficacy were performed to determine glibenclamide nanosuspension inhaler effect.Results: The results revealed that the mean particle sizes of the prepared nanosuspension ranged from 0.216 to 0.856 µm, zeta potential from +9 to +16 mV, the solubility ranged from 43% to 75%, the mass median aerodynamic diameter was 2.34 µm and the glucose level in rat was significantly reduced by about 60%.Conclusion: These results confirmed that glibenclamide nanosuspension inhaler enhance hypoglycemic effectiveness and reduce adverse effect of glibenclamide, opening up new dosage form in Diabetes mellitus treatment.

In vitro cytotoxicity and transfection efficiency of pDNA encoded p53 gene-loaded chitosan-sodium deoxycholate nanoparticles.

Purpose: The objective of this work was to formulate a delivery system of pDNA encoded p53 gene-loaded chitosan-sodium deoxycholate (CS-DS) nanoparticles, and to evaluate their influence on in vitro cytotoxicity and transfection efficiency of p53 gene. Methods: The prepared pDNA-loaded CS-DS nanoparticles were evaluated for morphology, particle size, zeta potential, entrapment efficiency %, in vitro release, in vitro cytotoxicity, and transfection efficiency. Results: The mean particle size ranged from from 96.5 ± 11.31 to 405 ± 46.39 nm. All nanoparticles had good positive zeta potential values. Entrapment efficiency % ranged from 38.25 ± 3.25 to 94.89 ± 5.67. The agarose gel electrophoresis confirmed the strong binding between plasmid and CS. The in vitro pDNA release from nanoparticles exhibited an initial burst effect followed by a sustained drug release over a period of 6 days. In vitro cytotoxicity against human Caco-2 cells showed low cell cytotoxicity of plain CS-DS nanoparticles, while pDNA-loaded CS-DS nanoparticles showed a cytotoxic effect with increasing nanoparticles' concentration. Gene transfection, analyzed by PCR and ELISA, showed a direct correlation between gene expression and concentration of pDNA. The highest expression of the gene was achieved with pDNA concentration of 9 µg/mL with 5.7 times increase compared to naked pDNA of the same concentration. Conclusion: The obtained results were very encouraging and offer an alternative approach to enhancing the transfection efficiency of genetic material-loaded chitosan-based delivery systems.

Formulation and In Vitro and In Vivo Evaluation of Lipid-Based Terbutaline Sulphate Bi-layer Tablets for Once-Daily Administration.

The objective of this study was to prepare and evaluate terbutaline sulphate (TBS) bi-layer tablets for once-daily administration. The bi-layer tablets consisted of an immediate-release layer and a sustained-release layer containing 5 and 10 mg TBS, respectively. The sustained-release layer was developed by using Compritol®888 ATO, Precirol® ATO 5, stearic acid, and tristearin, separately, as slowly eroding lipid matrices. A full 4 × 2(2) factorial design was employed for optimization of the sustained-release layer and to explore the effect of lipid type (X 1), drug-lipid ratio (X 2), and filler type (X 3) on the percentage drug released at 8, 12, and 24 h (Y 1, Y 2, and Y 3) as dependent variables. Sixteen TBS sustained-release matrices (F1-F16) were prepared by melt solid dispersion method. None of the prepared matrices achieved the targeted release profile. However, F2 that showed a relatively promising drug release was subjected to trial and error optimization for the filler composition to develop two optimized matrices (F17 and F18). F18 which consisted of drug-Compritol®888 ATO at ratio (1:6 w/w) and Avicel PH 101/dibasic calcium phosphate mixture of 2:1 (w/w) was selected as sustained-release layer. TBS bi-layer tablets were evaluated for their physical properties, in vitro drug release, effect of storage on drug content, and in vivo performance in rabbits. The bi-layer tablets showed acceptable physical properties and release characteristics. In vivo absorption in rabbits revealed initial high TBS plasma levels followed by sustained levels over 24 h compared to immediate-release tablets.

Custom fractional factorial designs to develop atorvastatin self-nanoemulsifying and nanosuspension delivery systems--enhancement of oral bioavailability.

Poor water solubility of a drug is a major challenge in drug delivery research and a main cause for limited bioavailability and pharmacokinetic parameters. This work aims to utilize custom fractional factorial design to assess the development of self-nanoemulsifying drug delivery systems (SNEDDS) and solid nanosuspensions (NS) in order to enhance the oral delivery of atorvastatin (ATR). According to the design, 14 experimental runs of ATR SNEDDS were formulated utilizing the highly ATR solubilizing SNEDDS components: oleic acid, Tween 80, and propylene glycol. In addition, 12 runs of NS were formulated by the antisolvent precipitation-ultrasonication method. Optimized formulations of SNEDDS and solid NS, deduced from the design, were characterized. Optimized SNEDDS formula exhibited mean globule size of 73.5 nm, zeta potential magnitude of -24.1 mV, and 13.5 µs/cm of electrical conductivity. Optimized solid NS formula exhibited mean particle size of 260.3 nm, 7.4 mV of zeta potential, and 93.2% of yield percentage. Transmission electron microscopy showed SNEDDS droplets formula as discrete spheres. The solid NS morphology showed flaky nanoparticles with irregular shapes using scanning electron microscopy. The release behavior of the optimized SNEDDS formula showed 56.78% of cumulative ATR release after 10 minutes. Solid NS formula showed lower rate of release in the first 30 minutes. Bioavailability estimation in Wistar albino rats revealed an augmentation in ATR bioavailability, relative to ATR suspension and the commercial tablets, from optimized ATR SNEDDS and NS formulations by 193.81% and 155.31%, respectively. The findings of this work showed that the optimized nanocarriers enhance the oral delivery and pharmacokinetic profile of ATR.

Optimized zein nanospheres for improved oral bioavailability of atorvastatin.

BACKGROUND: This work focuses on the development of atorvastatin utilizing zein, a natural, safe, and biocompatible polymer, as a nanosized formulation in order to overcome the poor oral bioavailability (12%) of the drug. METHODS: Twelve experimental runs of atorvastatin-zein nanosphere formula were formulated by a liquid-liquid phase separation method according to custom fractional factorial design to optimize the formulation variables. The factors studied were: weight % of zein to atorvastatin (X1), pH (X2), and stirring time (X3). Levels for each formulation variable were designed. The selected dependent variables were: mean particle size (Y1), zeta potential (Y2), drug loading efficiency (Y3), drug encapsulation efficiency (Y4), and yield (Y5). The optimized formulation was assayed for compatibility using an X-ray diffraction assay. In vitro diffusion of the optimized formulation was carried out. A pharmacokinetic study was also done to compare the plasma profile of the atorvastatin-zein nanosphere formulation versus atorvastatin oral suspension and the commercially available tablet. RESULTS: The optimized atorvastatin-zein formulation had a mean particle size of 183 nm, a loading efficiency of 14.86%, and an encapsulation efficiency of 29.71%. The in vitro dissolution assay displayed an initial burst effect, with a cumulative amount of atorvastatin released of 41.76% and 82.3% after 12 and 48 hours, respectively. In Wistar albino rats, the bioavailability of atorvastatin from the optimized atorvastatin-zein formulation was 3-fold greater than that from the atorvastatin suspension and the commercially available tablet. CONCLUSION: The atorvastatin-zein nanosphere formulation improved the oral delivery and pharmacokinetic profile of atorvastatin by enhancing its oral bioavailability.

Comparative study on the suitability of two techniques for measuring the transfer of lipophilic drug models from lipid nanoparticles to lipophilic acceptors.

Due to their particle size in the submicrometer range, lipid nanoparticles are suitable for parenteral administration. In order to obtain information on their potential in vivo performance, a simple and effective in vitro assay to evaluate the drug release behavior of such particles is required. This study compares the use of different experimental setups for this purpose. Lipid nanoparticles from trimyristin which were loaded with fluorescent lipophilic drug models (a temoporfin and Nile red) were used as donor particles. The transfer of the two drug models to multilamellar vesicles (MLV) and emulsion droplets as lipophilic acceptor compartments was examined. The determination of the transferred substance was performed either after separation by centrifugation or by an in situ flow cytometric technique. The transfer of temoporfin was slow to the acceptor MLV and very rapid to the acceptor emulsion. With both acceptors, the transfer of temoporfin stopped at a concentration much lower than the theoretical equilibrium values. The transfer of the less lipophilic drug Nile red was very rapid to both acceptors with equilibrium concentrations close to the expected values. The transfer results of temoporfin especially to the acceptor MLV obtained with the two detection techniques were comparable while the centrifugation technique indicated an apparently higher Nile red transfer rate than the flow cytometric technique. Both techniques are equally suitable to study the transfer of temoporfin, while the flow cytometric technique is advantageous to measure the very rapid transfer of Nile red.

In vitro cytotoxicity and bioavailability of solid lipid nanoparticles containing tamoxifen citrate.

The objective of this study was to evaluate the influence of solid lipid nanoparticles (SLN) loaded with the poorly water-soluble drug tamoxifen citrate (TC) on the in vitro antitumor activity and bioavailability of the drug. TC-loaded SLN were prepared by solvent injection method using glycerol monostearate (GMS) or stearic acid (SA) as lipid matrix. Poloxamer 188 or tween 80 were used as stabilizers. TC-loaded SLN (F3 and F4) prepared using GMS and stabilized by poloxamer 188 showed highest entrapment efficiency % (86.07 ± 1.74 and 90.40 ± 1.22%) and reasonable mean particle sizes (130.40 ± 9.45 and 243.80 ± 12.33 nm), respectively. The in vitro release of TC from F3 and F4 exhibited an initial burst effect followed by a sustained drug release. In vitro cytotoxicity of F3 against human breast cancer cell line MCF-7 showed comparable antitumor activity to free drug. Moreover, the results of bioavailability evaluation of TC-loaded SLN in rats compared to free TC indicated that 160.61% increase in the oral bioavailability of TC. The obtained results suggest that incorporation of the poorly water-soluble drug TC in SLN preserves the in vitro antitumor activity and significantly enhance oral bioavailability of TC in rats.

Development and evaluation of chitosan microspheres for tetanus, diphtheria and divalent vaccines: a comparative study of subcutaneous and intranasal administration in mice.

CONTEXT: There is a need to use the new technologies to induce immunity with minimum number of vaccination sessions to ensure compliance with reducing cost. OBJECTIVES: To develop single shot vaccines of tetanus, diphtheria and divalent toxoids microsphere's formulations and to induce their immune response after intranasal and subcutaneous administration in mice. MATERIALS AND METHODS: The microspheres were prepared using different concentrations of chitosan. Microsphere's morphology, particle size analysis, encapsulation efficiency and antigen integrity were performed and the best formulations were selected for in vitro and in vivo testing in mice. RESULTS: The developed microspheres have a yield percent of 70.3-91.5%. In vitro release of antigens indicated that tetanus release was increased up to 75 and 81% post T5 and TD5 formulations respectively, whereas diphtheria cumulative release increased up to 74 and 69% post D3 and TD5, respectively. DISCUSSION: Antibody levels produced were lower than that obtained from alum adsorbed vaccine but higher than the minimum level required to induce immunogenicity (>0.01 IU/mL). The subcutaneous route of administration was superior over the intranasal route in producing higher antibody levels. CONCLUSION: Chitosan microspheres were developed successfully and prove that chitosan represents a good candidate for vaccines delivery.

In Vitro and In Vivo Evaluation of Oxatomide ß -Cyclodextrin Inclusion Complex.

The objective of this study was to evaluate the influence of oxatomide ß-cyclodextrin inclusion complex on the physicochemical properties and bioavailability of the drug. Oxatomide ß-cyclodextrin solid complex was prepared with equimolar ratio of both oxatomide and ß-cyclodextrin in presence or absence of water soluble polymers using different techniques. The coevaporated complex prepared in presence of PVP-K15 showed a prompt drug release and significantly increased % dissolution efficiency (P < 0.05) compared to the pure oxatomide. Moreover, the results of bioavailability evaluation of this complex in rabbits compared to commercial drug product indicated a 73.15% increase in the oral bioavailability of oxatomide. In conclusion, inclusion complex of oxatomide with ß-cyclodextrin prepared by coevaporation in presence of PVP-K15 not only results in an enhancement of the oxatomide dissolution rate but also improves the bioavailability of oxatomide.

Formulation, characterization, and clinical evaluation of microemulsion containing clotrimazole for topical delivery.

The objective of the present study was to formulate and evaluate microemulsion systems for topical delivery of clotrimazole (CTM). The solubility of CTM in various oils was determined to select the oil phase of the microemulsion systems. Pseudoternary phase diagrams were constructed to identify the area of microemulsion existence. Five CTM microemulsion formulations (M1-M5) were prepared and evaluated for their thermodynamic stability, pH, refractive index, droplet size, viscosity, and in vitro release across cellulose membrane. Among the prepared microemulsion formulations, M3 (lemon oil/Tween 80/n-butanol/water) and M4 (isopropyl myristate/Tween 80/n-butanol/water) microemulsion systems were found to be promising according to their physical properties and CTM cumulative percentage release. Gel form of M3 and M4 were prepared using 1% Carbopol 940 as the hydrogel matrix. Both formulations were evaluated in the liquid and gel forms for drug retention in the skin in comparison to the marketed CTM topical cream and their stability examined after storage at 40°C for 6 months. Microemulsion formulations achieved significantly higher skin retention for CTM over the CTM cream. Stability studies showed that M4 preparations were more stable than M3. The in vitro anti-fungal activity of M4 against Candida albicans was higher than that of the conventional cream. Moreover, clinical evaluation proved the efficacy and tolerability of this preparation in the treatment of various topical fungal infections.