CONTROLLED-RELEASE OF ETHINYLESTRADIOL FROM ETHYLENE-VINYL ACETATE MEMBRANE

The studies on the permeability of ethinylestradiol (EE) through ethyl ene-vinyl acetate (EVA) copolymer membrane using a two-chambered diffu sion cell were carried out to develop the membrane controlled transder mal delivery system. To evaluate the effect of drug concentration in r eservoir, polyethylene glycol (PEG) 400 was added to saline solution a s a solubilizer and a sink condition was maintained in the receptor so lution. An increased vinyl acetate comonomer content in the EVA membra ne increased the drug release rare and permeability coefficient. A lin ear relationship existed between the permeation rate and the reciproca l of the membrane thickness. Ethinylestradiol-containing matrix was fa bricated with EVA copolymer to control the release of the drug. The re lease of EE from EVA matrix follows a diffusion controlled model, wher e the quantity released per unit area is proportional to the square ro ot of lime. The release rate of drug from EVA matrix increased with PE G 400 volume fraction, temperature and loading dose.