Arterial and venous blood sampling in pharmacokinetic studies: propranolol in rabbits and dogs.

Significant and persistent arterial-venous (A-V) plasma concentration differences of propranolol in unanesthetized rabbits and dogs following intravenous bolus injection or intravenous infusion were found. Both arterial and venous data were then subjected to extensive pharmacokinetic analyses utilizing standard procedures. Marked differences in calculated noncompartmental pharmacokinetic parameters such as the steady-state volume of distribution, absolute amount present in the body, and relative contribution of the terminal phase were obtained. The appropriateness of using venous propranolol plasma data for multicompartmental mammillary pharmacokinetic modeling analysis was discussed. The significance of the present study in pharmacokinetic and pharmacodynamic investigations of propranolol in humans remains to be explored.