Drug Permeation through Membranes II: Simultaneous Dissolution and Permeation of Drug from Solid Dosage Forms

Abstract

<h2>Abstract:</h2> The simultaneous dissolution and permeation of a drug from solid oral dosage forms were analyzed by a treatment based on Fick's second law of diffusion. The analysis shows that dissolution rate constants can be obtained from the permeation lag time, while the coefficients of permeability are estimated, as usual, from the rate of drug transfer across the membrane under steady-state conditions. Drug-excipient interactions, if any, would be expected to affect the rate of drug transfer across the membrane. Therefore, from a single experiment, the dissolution rate and the extent of drug-excipient interaction can be obtained. The equation was tested by dissolution-permeation measurements on two amobarbital formulations.