EFFECT OF CASTING SOLVENT ON PERMEABILITY OF ANTIHYPERTENSIVE DRUGS THROUGH EUDRAGIT RS 100 FILMS

Abstract

In the present work, Eudragit RS 100 films were prepared and evaluated as rate controlling membrane
for t ransdermal dr ug del iver y sy st ems. Acet one-met hanol ( 8: 2) , chlor oform-met hanol ( 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 15% w/w of the polymer was used as a plasticizer
in the preparation films. The casting solvent 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 Permeabilit y Coefficient . Both Water vapour t ransmission and Drug
diffusion rate followed zero order kinet ics. 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
t ranspor t 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. Eudragit RS 100 films employed with ethyl acetate:methanol in
8:2 ratio as casting solvent yielded low area of patch with desired release rate for both drugs .