Thesis (M.Sc. in Pharm)--Chulalongkorn University, 1993

The in-vitro permeation behaviors of a synthetic membrane, silastic^R, and a biological membrane, pig skin, were characterized using piroxicam as a model drug. The experiments had been carried out using modified - Franz diffusion cells. Various gel bases containing 2% piroxicam were prepared to study the in-vitro permeation of the drug. The piroxicam fluxes from four selected gel bases : pluronic F-127, carbopol-940, hydroxypropyl methylcellulose, and hydroxyethyl cellulose gel bases, through silastic^R were correlated with the fluxes through pig skin (r^2=0.9631). The carbopol-940 gel base yielded the highest flux. It was, therefore, used for further study of effects of some additives on steady-state flux of piroxicam. The additives studied included 10% and 20% isopropyl alcohol, 5% and 10% propylene glycol, 0.5 % and 1.0 % Tween 20, and 0.5 % and 1.0 % Brij 30. Among the formulations evaluated, the piroxicam flux from carbopol-940 gel base containing 1.0 % Brij 30 gave the highest in-vitro permeation rate through pig skin. In conclusion, all the results indicated that silastic^R can be used instead of pig skin for diffusion rate comparison of gel preparations containing components which do not have any effects on the membranes.