Frog intestinal perfusion to evaluate drug permeability: application to p-gp and cyp3a4 substrates.

To evaluate the reliability of using in situ frog intestinal perfusion technique for permeability assessment of carrier transported drugs which are also substrates for CYP enzymes. Single Pass Intestinal Perfusion (SPIP) studies were performed in frogs of the species Rana tigrina using established method for rats with some modifications after inducing anesthesia. Effective permeability coefficient (P eff) of losartan and midazolam was calculated in the presence and absence of inhibitors using the parallel-tube model.