PROCESS OF DRUG-RELEASE WITH ORAL DOSAGE FORMS WITH A LIPIDIC GELUCIRE MATRIX

The process of drug release out of dosage forms made of the drug dispe rsed in a lipidic Gelucire is considered. The process is based on the following three ideas: first, the liquid dissolves the drug in contact with it and occupies its previous place; second, the drug diffuses ou t of the dosage form through the liquid located in it, and third, the diffusivity of the drug varies with the concentration of the liquid in an exponential way. These assumptions are drawn from the following ex perimental observations: no change in dimension of the dosage form tak es place; the amount of drug release after a long time is greater than that evaluated with a constant diffusivity. Good agreement is obtaine d between the kinetics of drug release obtained either by calculation or from experiments using in vitro tests.