CHROMATOGRAPHIC ANALYSIS AND PHARMACOKINETIC INVESTIGATION OF CEPHALOGLYCIN AND ITS METABOLITES IN MAN

Abstract

Metabolism and pharmacokinetics of cephaloglycin in man were investigated. High performance liquid chromatographic and gas chromatographic-mass spectrometric analyses of metabolites excreted in human urine following oral administration of cephaloglycin revealed that cephaloglycin was biotransformed in two pathways i.e. elimination of 3-acetyl group and hydrolysis of side chain amide linkage. The former yielded deacetylcephaloglycin, a part of which further underwent lactonization to deacetylcephaloglycin lactone, and the latter led to benzoyl formic acid via phenylglycine. The urinary excretion amounts of these metabolites and intact cephaloglycin were determined by a reversed phase ion pair high performance liquid chromatography. The average total excretion amounts at infinite time accounted for 0.50% of the administered dose for intact cephaloglycin, 17.09% for deacetylcephaloglycin, 0.35 for deacetylcephaloglycin lactone, and 0.86% for benzoyl formic acid. The excretion of phenylglycine was less than 0.2%, its chromatographic peak being too small to allow accurate determination. The rate constants for absorption, metabolism, and urinary excretion were estimated by the moment analysis of the excretion rate-time curves.