The effect of displacement from protein binding on serum and tissue fluid levels of cephazolin

Abstract

Displacement of cephazolin, a highly protein-bound beta-lactam antibiotic, by sulpha-phenazole was studied in vitro and in vivo. In vitro, the sulphonamide was effective in displacing the antibiotic from its binding sites at the concentration 100--1000 mumol 1(-1). In vivo, both the serum and the tissue fluid concentration of free cephazolin increased significantly in rats concomitantly treated with sulphaphenazole.

Effects of enzyme inducers and inhibitors on the pharmacokinetics of intravenous omeprazole in rats

“…This could be due to displacement of the binding of omeprazole by the enzyme inhibitors. Displacement of plasma (serum) protein binding of tolbutamide [34] and cefazolin [35] by sulfaphenazole, and of oxprenolol and propranolol by SKF 525-A [36] were also reported. The time intervals between pretreatment of enzyme inhibitors and omeprazole dosing are short (0, 1, 1 and 2 h for sulfaphenazole, SKF 525-A, quinine and troleandomycin, respectively), therefore, it could be expected that the inhibitors were present in the plasma.…”