Pharmacokinetics of intraperitoneally instilled aminophylline, terbutaline and tobramycin in pigs.

Introduction: Venous catheters are sometimes difficult or even impossible to insert and may also be associated with serious complications. This study was carried out to investigate whether intraperitoneal administration of drugs may be an alternative to the intravenous route in patients with limited vascular access.

Materials And Methods: Three drugs commonly in use in clinical practise, aminophylline, terbutaline and tobramycin, were administered to pigs intravenously and intraperitoneally in small volumes. Serum concentrations were analysed over a period of 6 h and pharmacokinetic key variables for each drug were calculated.

Results: Aminophylline (theophylline), terbutaline and tobramycin were absorbed from the peritoneal space and into systemic circulation. For theophylline, the concentration/time profiles after intraperitoneal and after intravenous administration were almost identical, and the intraperitoneal bioavailability was calculated to 0.94. For terbutaline and tobramycin, the intraperitoneal absorption was delayed without any initial peak. Moreover, the intraperitoneal bioavailability was lower than for theophylline (0.71 and 0.65, respectively).

Conclusion: The pharmacokinetic properties after intraperitoneal administration differed among the three drugs, but the results are encouraging and provide a basis for further investigation in humans.