Determination of the cephalosporin Ro 13‐99041 in plasma, urine, and bile by means of ion‐pair reversed phase chromatography

Abstract

AbstractAn HPLC method has been developed for the determination of the cephalosporin antibiotic Ro 13‐9904 in plasma, urine, and bile of dogs and of human volunteers using the technique of ion‐pair chromatography with a LiChrosorb RP‐18 column. The three mobile phases employed contained tetrapentyl‐, tetraoctyl‐ and hexadecyltrimethyl‐ammonium bromide, respectively, as lipophilic counterions. The chromatographic conditions chosen allowed simple and rapid sample preparation. Plasma was deproteinized with ethanol and the supernatant was directly injected onto the column; urine and bile were diluted with mobile phase and injected without any purification. The detection limit for the cephalosporin was about 0.5 μg/ml for plasma samples and approximately 5 μg/ml for bile and urine.