Aprotinin turn-over studies in dog and in man with severe acute pancreatitis.

The elimination of aprotinin after intravenous infusion was exponential until 95% of the dose was cleared from the plasma after 1 h in dogs with bile-induced pancreatitis. The half-life of this part of the elimination was 10 min. The concentration of aprotinin in the peritoneal fluid reached a maximum plateau after 1 h. Direct intra-abdominal infusion of aprotinin was followed by a relatively slow elimination of the inhibitor from the cavity. One hour after the infusion the concentration of aprotinin in the peritoneal exudate was about 50% of the initial value. Four hours later the concentration of inhibitor with unchanged immunoreactivity and inhibiting capacity was still about 25% of the initial value. Based on the results of this experimental study an intraperitoneal dosage schedule for aprotinin was tested in three patients with haemorrhagic pancreatitis. A total amount of 14 X 10(6) KIU was given in repeated dosages during 18 h. This resulted in a minimum level of aprotinin in the peritoneal exudate of about 10 mumol/l. According to our earlier published data this level should largely block trypsin-induced effects relevant in pancreatitis. In conclusion; due to the rapid elimination of aprotinin from plasma, after i.v. application a therapeutically useful concentration is never reached in the peritoneum, while the elimination from the peritoneum is relatively slow, thus providing therapeutically useful concentrations which can be maintained for some time after i.p. application.