CALCULATION OF THE BLOOD LEVEL OF A DRUG TAKEN ORALLY WITH A DIFFUSION-CONTROLLED DOSAGE FORM

Oral dosage forms with controlled release are generally investigated e ither by in vitro or in vivo tests and the problem of correlating thes e results appears. A numerical model is built, taking into account the characteristics of drug release out of the dosage form along the gast rointestinal tract, the stages of absorption in the blood compartment and of elimination. The dosage form is obtained by dispersing theophyl line as a drug in Eudragit RS playing the role of a polymer matrix. Th e process of drug release is controlled by diffusion, with a constant diffusivity. The following results are obtained: the kinetics of relea se of the drug out of the dosage form, the kinetics of the drug in the blood compartment, and the kinetics of drug elimination.