Pooja Pawar

The present study was aimed to develop generic formulation of sustained release matrix tablets of Nevirapine using TSP as a hydrophilic polymer. The tamarind seed polysaccharide was extracted from tamarind kernel powder and this polysaccharide was utilized in the formulation of matrix tablets containing Nevirapine by wet granulation technique and evaluated for its drug release characteristics. TSP is a hydrophilic and rate controlling polymer. Granules were prepared and evaluated for loose bulk density, tapped density, compressibility index and angle of repose, shows satisfactory results. Formulation was optimized on the basis of acceptable tablet properties (hardness, friability, drug content and weight variations.), in vitro drug release and stability studies. All the formulations showed compliance with pharmacopoeial standards. The in vitro release study of matrix tablets were carried out in phosphate buffer pH 7.4 for 12hr. Among all the formulations, F5 shows 99.062% better controlled release at the end of 12 hr. The results indicated that a decrease in release kinetics of the drug was observed by increasing the polymer concentration. The release data was fitted to various mathematical models such as, Higuchi, Krosmeyer-Peppas, first-order, and zero order to evaluate the kinetics and mechanism of the drug release. The drug release of optimized formulations F5 follows Krosmeyer-Peppas kinetics and the mechanism was found to be diffusion coupled with erosion (non-Fickian diffusion). The stability studies were carried out according to ICH guideline which indicates that the selected formulation were stable.

To increase the low bioavailability and short ocular residence time of lomefloxacin eye drops, aqueous solutions of drug in chitosan/ Pluronic (poloxamer) were prepared to identify suitable compositions with regard to gel forming properties and drug release behaviour. Mixtures of solutions of Pluronic (10-25% w/w) with chitosan (0.1-0.3% w/w) of different molecular weights (Mw) were prepared. Lomefloxacin release was determined using a membrane less dissolution model in artificial tear solution up to 8 hours and the samples were analyzed spectrophotometrically at 281nm. The rheological behaviour of solutions in response to dilution or temperature changes and also the phase change temperature (PCT) were determined using a brookfield’s viscometer. Antimicrobial effect of the solutions was studied in nutrient agar using Staphylococcus aureus by using agar well diffusion method. The formulation consisted of 15% Pluronic and 0.1% low Mw chitosan, with the highest release efficiency (41.952 %) , is suggested as a suitable ophthalmic preparation for sustained release of lomefloxacin HCl. It was liquid in non-physiologic conditions (pH 4 and 25ºC) and transferred to the gel form upon physiologic conditions (pH 7.4 and 37ºC). The PCT of this in situ gel did not change upon dilution.