DEVELOPMENT AND IN-VITRO EVALUATION OF NITRENDIPINE TRANSDERMAL FORMULATIONS USING EXPERIMENTAL-DESIGN TECHNIQUES

In the present study nitrendipine was incorporated into gels and its e fficacy to permeate human epidermis was examined in vitro. A prelimina ry study was carried out in order to estimate the effect of the type o f enhancer, the concentration of enhancer and the concentration of gel ling agent on the flux of nitrendipine, using a 2(3) factorial design. The type of enhancer and the concentration of enhancer were further e valuated as they were found to be important for nitrendipine flux, whi le the concentration of the gelling agent was kept at its optimum leve l in all experiments. In order to increase further the flux of nitrend ipine, the combination of two enhancers, glycerol monooleate (GMO) and N-methyl-2-pyrrolidone (NMP), which act via different mechanisms, at three concentration levels was examined, using the response surface me thod. The results indicate that higher flux values were obtained when NMP was greater than 4.5% w/w and GMO between 5.0 and 9.5% w/w, in the vehicle.