Objective: The aim of present study was to apply Quality by Design (QbD) for development of an optimized ion sensitive in situ ophthalmic gel Olopatadine HCl to increase drug residence time, ocular bioavailability and decreased dosing frequency of drug administration. Method: To develop the optimized formulation, 3 2 full factorial design method was adopted. The material attributes and critical quality attributes of the in situ gel were identified. Materials attributes were amount of Sodium Alginate and HPC and CQA's identified were % drug release and viscosity. The formulations were assessed for appearance, gelling ability, sterility, pH, drug content, viscosity, drug release through cellophane membrane, drug release through corneal membrane of goat, and stability study as per ICH guidelines. Formulations F3 and F8 were selected and were again analysed by grid analysis. Result: The optimized batches exhibited all results in acceptable limits. F8 was found to be the best formulation from the nine formulations developed by 3 2 full factorial design. The optimized formulation showed better drug release when compared with marketed formulation. Conclusion: The study revealed that the in situ gelling system of Olopatadine HCl sustained the effect of drug up to 10 hours. The formulation F8 extended the release of drug up to 10 hours as compared to marketed preparation of Olopatadine HCl, Zyopta (solution), which gives 98.39% drug release within 6 hours.

Posaconazole exerts an extended spectrum of antifungal activity against various strains of clinically relevant moulds and yeasts. In recent years, antifungal triazole posaconazole has become increasingly important for the prophylaxis and treatment of systemic mycoses. After oral administration of posaconazole, absolute bioavailability has been estimated to range from 8% to 47%. Pharmaceutical co-crystallization is a promising approach for improving dissolution rate or manipulating other physical properties of API. The objective of this study is to improve the dissolution rate of posaconazole by co-crystallization. A 1:1 stoichiometric co-crystals of adipic acid were prepared by solvent assisted grinding method. The prepared co-crystals were subjected to solid-state characterization by FTIR, PXRD and DSC studies. The physicochemical properties of posaconazole and co-crystals were assessed in terms of melting point, flowability and dissolution rate. The results indicated improvement in flow property and dissolution rate. In vitro dissolution profile of co-crystals showed a significant increased dissolution of posaconazole from initial period in 0.1 N hydrochloric acid solution. The dissolution efficiency for posaconazole-adipic acid co-crystal was 61.65 % against posaconazole, 46.58 %. Thus, cocrystallization can be a promising approach to prepare posaconazole-adipic acid co-crystals with improved physicochemical properties.