Pharmacological studies on carbapenem antibiotics. I. Metabolism of PS-5 in animal tissues.

After injection into mice and dogs, PS-5 showed a very rapid decrease in its blood concentration, compared with cefazolin. Using in vitro experiments with tissue homogenates and acetone powder preparations, the kidney was found to be the primary site of PS-5-inactivation, although the extent of the inactivation varied depending on the species of animals. The comparative stability data of PS-5, NS-5 (deacetylated PS-5), thienamycin and N-formimidoylthienamycin in kidney homogenates of mouse, rabbit, dog and man are presented. Bilateral nephrectomy and the injection of ethylenediaminetetraacetate seemed to prolong the survival time of PS-5 in rats and mice respectively.