Effect of Casting Solvent on Permeability of Antihypertensive Drugs through Cellulose Acetate Films

In the present work, Cellulose acetate films were prepared and evaluated as rate controlling membrane for transdermal drug delivery systems. Acetone-methanol (8:2), chloroform-methanol (8:2), dichloromethane-methanol (8:2) and ethyl acetate-methanol (8:2) were used as solvents in the preparation of films. Dibutyl phthalate at a concentration of 40% w/w of the polymer was used as a plasticizer in the preparation films. The solvent evaporation technique was found to be giving thin uniform films. The dry films were evaluated for Physical appearance, Thickness uniformity, Folding endurance, Water Vapour Transmission, Drug diffusion and Permeability Coefficient. Both Water vapour transmission and Drug diffusion rate followed zero order kinetics. The mechanism of drug release was governed by peppas model. The diffusion exponent of release profiles (slope) has a value of n>1, which indicates non analmous transport diffusion. The results obtained in the present study thus indicated that the solvents used in the preparation of films have been shown significant influence on the water vapour transmission, drug diffusion and permeability of the films. Cellulose acetate films employed with ethyl acetate:methanol in 8:2 ratio as casting solvent shown high Permeability when compared to other films for both drugs.