[Assay of cefotaxime and desacetylcefotaxime in plasma and urine by high performance liquid chromatography].

The authors propose an assay technique for cefotaxime and desacetylcefotaxime in the plasma and urine, using high performance liquid chromatography. The proteins are precipitated by adding propanol-2 to 100 microliter of plasma or urine. After centrifugation, the supernatant is extracted by a mixture of chloroform and isoamyl alcohol. The cephalosporins remain in the superior aqueous phase and a fraction of this phase is injected into the chromatograph. The cefotaxime, desacetylcefotaxime and cephaloridine (internal standard) are separated on a Radial Pak C 18 column by ion-binding chromatography. The mobile phase consists of a mixture of distilled water and acetonitrile (830/170, V/V) with the addition of an ampoule of Pic A (tetrabutylammonium phosphate). This rapid, specific and sensitive micro-method can be used for the assay of these antibiotics in adults and children, for therapeutic monitoring and for pharmacokinetic studies.