Comparison between the pharmacokinetic properties of mezlocillin when given intravenously as a bolus injection or as an infusion.

6-[(R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenyl-acetamido]-penicillanic acid sodium salt (mezlocillin, Baypen) in doses of 5.0 g was given i.v. as an infusion or as a bolus injection to 5 healthy volunteers. 5 min after the completion of the infusion, the mean serum concentration was 430 +/- 81 microgram/ml compared to 424 +/- 91 microgram/ml after the bolus injection. The half-lives were 1.31 +/- 0.24 h and 1.72 +/- 0.21 h, respectively. These results indicate that differences in serum concentrations between various investigators probably can be attributed to differences in body size and do not seem to depend on the administration route.