Determination of cephalosporins in biological material by reversed-phase liquid column chromatography

Seven cephalosporins (β-lactam antibiotics), viz. cefazolin, cephalotin, cefoxitin, cefotaxime, cefamandole, cefuroxime and cefoperazone (T 1551) were determined in biological material. The compounds were extracted from acid-treated body fluids into chloroform—1-pentanol (3:1) and re-extracted into a small volume of an aqueous phase at pH 7, which was injected into the chromatographic column. The chromatographic support was μBondapak C_1a (10 μm) and the mobile phase was a mixture of 0.01 M acetate buffer (pH 4.8) and methanol or acetonitrile. Detection limits are about 50 ng/ml for extractions from 1 ml of serum and have permitted pharmacokinetic studies of the seven cephalosporins.