Vilazodone-phospholipid mixed micelles for enhancing oral bioavailability and reducing pharmacokinetic variability between fed and fasted states.

Despite the effectiveness and high tolerability of vilazodone (VLZ) as an antidepressant, its use is still limited due to its poor solubility and food dependent absorption. This study aims to load VLZ-phospholipid complex into self-assembled micelles forming VLZ-PL mixed micelles (VLZ-PL-MM), that can enhance VLZ solubility, improve its bioavailability and reduce the pharmacokinetic variability between the fed and fasting conditions. The effect of surfactant type and concentration was assessed using four different non-ionic surfactants (Brij 58, Tween 80, Labrasol and Pluronic F127) in four different weight ratios between the drug-complex and surfactant (1:0.5, 1:1, 1:2 and 1:3 w/w). Two VLZ-PL-MM formulae prepared using Brij 58 and Labrasol in 1:3 w/w ratio were selected as optimised ones since they have the highest encapsulation efficiency (100.83 and 93.87%, respectively), a particle size below 250 nm (206.73 and 221.33 nm, respectively) and negative zeta potential values (-29.63, -17.20 mV, respectively). Lyophilisation of these formulations using 3% sucrose was successful with no statistical changes in particle size and zeta potential upon rehydration. Both formulations elicited faster and higher in-vitro drug release profiles compared to the pure drug and the marketed tablet. In addition, both selected formulae improved ex-vivo permeation across rabbit intestinal membrane compared to the pure drug and the marketed tablet, with marked superiority of the one prepared using Brij 58. The results of the in-vivo study in male albino rabbits revealed similar AUC0-24 values after the oral administration of the best achieved VLZ-PL-MM system under fed and fasted conditions (769.89 and 741.55 ng.h mL-1, respectively). On the other hand, the marketed product showed significantly lower values of the AUC0-24 relative to the VLZ-PL-MM system and there was a marked enhancement of absorption of drug from the marketed product in presence of food (244.24 and 174.96 ng.h mL-1 under fed and fasted conditions, respectively). In addition, VLZ concentrations in the brain after 24 h obtained from the selected VLZ-PL-MM were significantly higher than those obtained from marketed tablet under fed and fasted conditions. Thus, the phospholipid mixed micelles formulation enhances the oral bioavailability of the poorly soluble drug and reduces the pharmacokinetic variability between fasting and fed conditions.

Insulin Mucoadhesive Liposomal Gel for Wound Healing: a Formulation with Sustained Release and Extended Stability Using Quality by Design Approach.

The present study deals with the formulation of topical insulin for wound healing with extended stability and sustained release, by applying quality by design concepts. Insulin has been promoted as a promising therapeutic wound healing agent. Topical formulation of insulin faced major problems, as it cannot be delivered safely to the wound with a controlled rate. Formulation of insulin-loaded vesicles in optimized bio-adhesive hydrogels has been explored to ensure a safe delivery of insulin to wounds in a controlled manner. Quality by design (QbD) was applied to study the effect of several critical process parameters on the critical quality attributes. Ishikawa diagram was used to identify the highest risk factors, which were screened by a fractional factorial design and augmented by Box-Behnken design. The optimized formula was incorporated into a mucoadhesive gel, which was further subjected to stability and clinical studies. An optimized formula was obtained with a particle size of 257.751 nm, zeta potential - 20.548 mv, 87.379% entrapment efficiency, and a release rate of 91.521 µg/cm2/h. The results showed that liposomal insulin remained stable for 6 months in aqueous dispersion state at 4°C. Moreover, the release was sustained up to 24 h. The clinical study showed an improvement in the wound healing rate, 16 times, as the control group, with magnificent reduction in the erythema of the ulcer and no signs of hypoglycemia. Insulin-loaded liposomal chitosan gel showed a promising drug delivery system with high stability and sustained release.

Preparation and in vitro/in vivo evaluation of antimicrobial ocular in situ gels containing a disappearing preservative for topical treatment of bacterial conjunctivitis.

The study aimed to formulate and evaluate levofloxacin hemihydrate ocular in situ gels along with freshly prepared disappearing preservative reported to be safer to human eyes. Formulae were prepared using thermosensitive (PF127 and PF68) or ion-activated (Gelrite) polymers. They were evaluated for gelation temperature (GT), capacity, content uniformity, pH, rheological behavior, in vitro drug release with kinetic analysis. Best formulae were exposed to storage effect to select the optimum formula that was subjected to different sterilization methods and in vivo evaluation. The prepared disappearing preservative (sodium perborate monohydrate) proved to be active oxidative preservative and compatible with our formulae. F9 (24% PF127, 15% PF 68, 0.5% levofloxacin hemihydrate, and 0.0025% sodium perborate monohydrate) showed prolonged drug release (12 h), acceptable GT, viscosity, and pH. It remained stable over 3 months at two temperatures and was best sterilized by filtration. It showed longer residence time (12 h) in rabbits' eye fluids compared with the Levoxin® eye drops (4 h). This successful attempt of using thermo-gelling system along with a disappearing type of preservatives would allow the use of these systems to achieve sustained release of antimicrobial drugs with minimum risk of eye damage improving patient compliance and treatment efficacy.

Brain targeted solid lipid nanoparticles for brain ischemia: preparation and in vitro characterization.

This study aims at formulating solid lipid nanoparticles (SLNs) of Vinpocetine (VIN) to be used as a brain targeted sustained drug-delivery system. VIN is a derivative of vincamine alkaloid, used for chronic cerebral vascular ischemia. However, it suffers from low bioavailability and short half-life. Its oral bioavailability is recorded to be between 7 and 55%. Its elimination half-life is 1-2 h so it would be a good candidate for a sustained drug-delivery system. VIN SLNs were prepared using modified high shear homogenization followed by ultrasonication technique. The effect of incorporating different lipids at different concentrations of various surfactants was investigated. The VIN SLNs were characterized by entrapment efficiency percent (EE%), particle size distribution, zeta-potential, and cumulative released percent after 96 h. The EE% ranged between 83.34% ± 0.95-94.56% ± 0.11 due to the lipophilic character of VIN. The mean particle size measured ranged from 123 nm-464 nm. The cumulative released percent after 96 h ranged from 23.55% to 75.67% showing a controlled release profile. Formula (F32) composed of 5% glyceryl monostearate (GMS) and stabilized by 2% surfactant mixture [Tween 80, Pluronic F 68 (1:1)] was the most appropriate formula for brain delivery having EE% of 89.09% ± 1.49, zero-order release kinetics with cumulative released percent of 72.12% after 96 h, zeta-potential of -11.3 ± 0.97 mV. It showed a unimodal size distribution with particle size ≈ 90 nm and polydispersity index of 0.121. The formula of choice in this study exhibited a zero-order sustained release profile and met the requirement for a brain targeted SLN so it could be a promising formula to deliver VIN to the brain.

Colon-targeted celecoxib-loaded Eudragit® S100-coated poly-ε-caprolactone microparticles: preparation, characterization and in vivo evaluation in rats.

CONTEXT: Celecoxib suffers from low and variable bioavailability following oral administration of solutions or capsules. Recent studies proved that chemoprevention of colorectal cancer is possible with celecoxib. OBJECTIVE: This work aimed to tailor colon-targeted celecoxib-loaded microparticles using time-dependant and pH-dependant coats. Estimation of drug pharmacokinetics following oral administration to fasted rats was another goal. METHODS: A 2³ factorial design was adopted to develop poly-ε-caprolactone (PCL) celecoxib-loaded microparticles (F1-F8). To minimize drug-percentages released before colon, another coat of Eudragit® S100 was applied. In vitro characterization of microparticles involved topography, determination of particle size and entrapment efficiency (EE %). Time for 50% drug release (t(50%)) and drug-percentages released after 2 hours (Q(2h)) and 4 hours (Q(4h)) were statistically compared. Estimation of drug pharmacokinetics following oral administration of double-coat microparticles (F10) was studied in rats. RESULTS: PCL-single-coat microparticles were spherical, discrete with a size range of 60.66 ± 4.21-277.20 ± 6.10 µm. Direct correlations were observed between surfactant concentration and EE%, Q(2h) and Q(4h). The PCL M.wt. and drug: PCL ratio had positive influences on EE% and negative impacts on Q(2h) and Q(4h). When compared to the best achieved PCL-single-coat microparticles (F2), the double-coat microparticles (F10) showed satisfactory drug protection; Q(2h) and Q(4h) were significantly (P < 0.01) decreased from 31.84 ± 1.98% and 54.72 ± 2.10% to 15.92 ± 1.78% and 26.93 ± 2.76%, respectively. When compared to celecoxib powder, F10 microparticles enhanced the bioavailability and extended the duration of drug-plasma concentration in rats. CONCLUSION: The developed double-coat microparticles could be considered as a promising celecoxib extended-release colon-targeting system.