[Metabolism and distribution of bupivacaine-experiments in rats. II. Distribution and elimination (author's transl)].

To avoid the influence of general anaesthetics on the functions of most organ systems, the present experiments were carried out in unanaesthetized rats. Blood concentrations in the aorta, V. portae and Vv. hepaticae as well as urinary and biliary excretions of bupivacaine were studied after either intravenous or enteral administration. From the course of the aortic bupivacaine concentrations after i.v. injection the following pharmacokinetic data were derived: t1/2 = 24,7 min; k2 = 1,467 h; V = 1,492 1. Absorption of bupivacaine from the jejunum is rapid. The hepatic clearance of bupivacaine in the rat is 12 ml/kg b.w..min-1. The biliary excretion of bupivacaine in the rat is very small; therefore the enterohepatic circulation of this substance may be considered neglible.