PREDICTION OF IN-VIVO BLOOD LEVEL WITH CONTROLLED-RELEASE DOSAGE FORMS - EFFECT OF THE GASTROINTESTINAL-TRACT TIME

The process of in-vivo drug transfer is very complex in the case of or al dosage forms with controlled release. A numerical model taking all the known facts into account, including the release of the drug contro lled by diffusion through the dosage form along the gastrointestinal t ract, the kinetics of absorption in the blood compartment and the kine tics of elimination was constructed. Various parameters intervene in a n important manner For a given drug: the size of the dosage form which is associated with the rate of release of the drug, and the dose freq uency in multidosing. Some emphasis is placed upon the gastrointestina l tract time which appears to be the main and first parameter to be co nsidered in preparing a dosage form.