Distribution kinetics and intestinal absorption of practolol in the rat.

1. After intravenous injection of practolol the blood concentration-time curve is fitted by a bi-exponential function. A two compartment open system model is therefore a minimal requirement in order to describe adequately the distribution of the drug in the body.2. The parameters of the two compartment model for practolol were determined. The mean values for the ;fast disposition' half life and the ;slow disposition' half life were 0.5 min and 13.3 min, respectively.3. The rate constants of distribution and elimination were similar in different animals. The volume of the central compartment was related to the weight of the animal.4. The absorption of practolol from an intestinal site was measured by its appearance in the blood. The rate constant for this process was estimated to be 0.03 min(-1).