Abstract

Verapamil free base and diltiazem free base, were prepared from corresponding salt forms and characterized prior to evaluate their in vitro diffusion kinetics from ethylenevinylacetate-vinylacetate 40% copolymer membrane. Base forms of original drug molecules exhibited enhanced trans membrane permeation as compared to corresponding salt forms; facilitating to deliver the drug in a controlled manner, across a convenient small surface area of delivery device.