Estimation of the effective amount entering the body for drugs subject to enterohepatic recirculations.

A pharmacokinetic model is used to take into account multiple recirculations of drug occurring at various times after gall bladder emptying. If a dose D is initially administed, due to recirculation, an effective amount A* reaches the body. This value A* is expressed as a function of D and the model parameters, after oral administration or intravenous injection. Using areas under curves in two different situations, the reabsorption rate may be identified.