ORAL DOSAGE FORMS WITH A CORE AND SHELL WITH THE SAME POLYMER CONTAINING DIFFERENT DRUG CONCENTRATIONS

In order to achieve the controlled release of a drug, dosage forms mad e of a core and shell were developed and studied. The core and shell w ere obtained by dispersing the drug in the same polymer, with differen t concentrations of drug in the core and in the shell. A numerical mod el taking into account all the known facts was built and tested. The p rocess is as follows: the liquid diffuses into the polymer, dissolves the drug and enables the drug to diffuse out of the form through the l iquid located in the polymer. Four parameters appear to be of great in terest: the radius of the core, the thickness of the shell, and the in itial concentrations of drug in the core and in the shell. The results are given by using either the kinetics of release of drug or the rate at which the drug is released during the process.