DESIGN AND EVALUATION OF TOPICAL HYDROGEL FORMULATION OF DICLOFENAC SODIUM FOR IMPROVED THERAPY

Topical gel preparations are intended for skin application or to certain mucosal surfaces for local action or transdermal penetration of medicament or for their emollient or protective action. Topical delivery of drugs can be achieved by incorporating drug into the gel matrix for effective delivery of drugs, thus avoiding first pass metabolism and for increased local action in pain management and skin diseases. NSAID’s are non-steroidal drugs having excellent anti-inflammatory and analgesic activity but NSAID’s produces GIT ulceration, liver and kidney trouble especially in case of oral administration. In view of adverse drug reaction associated with oral formulations, many NSAID’s are increasingly administered by topical route. Hydrophilic polymers like Guar gum and Carbopol 940 of varying concentrations were used in an attempt to develop topical hydrogel formulations of diclofenac sodium. Evaluation tests for visual appearance, pH, viscosity, spreadability, assay, in vitro drug release, ex vivo drug release were carried out. In vitro drug release studies were carried out by using USP V dissolution apparatus. The effects of polymer composition on the rate of ex vivo drug release from the gel formulations were examined through rat abdominal skin mounting on franz diffusion cell at 32 ± 0.5^oC. No prominent changes in physicochemical properties of formulation were observed after  exposure to accelerated conditions of temperature (40 ± 2^oC) and humidity conditions (75 ± 5%RH). The gel formulation consisting of 1% w/v Guar gum 1% w/v Carbopol940 at 1:1 ratio was found to be suitable for topical application based on invitro evaluation and exvivo permeation studies. These results suggest the feasibility of the topical gel formulation of diclofenac sodium.