Determination of cefotaxime and desacetylcefotaxime in cerebrospinal fluid by solid-phase extraction and high-performance liquid chromatography.

A high-performance liquid chromatographic procedure has been developed for the measurement of cefotaxime and desacetylcefotaxime in cerebrospinal fluid. Both compounds were isolated from cerebrospinal fluid samples using solid-phase extraction (SPE). LiChrolut RP-18 (200 mg; 3 ml) columns and a mixture of methanol-phosphate buffer pH 7 (1:1) were applied to elute cefotaxime and its desacetyl metabolite. The separation was performed on a LiChrospher 100RP-18 (5 microm; 250 x 4 mm I.D.) column. The mobile phase consisted of 0.01 M acetate buffer pH 4.8-methanol (85:15), flow-rate was 1.5 ml/min. Cefotaxime and desacetylcefotaxime were detected at a wavelength of 254 nm by UV-Vis detector. The range of concentrations for method calibration and for analytical studies was 1.56-100 microg/ml. The quantitation limit in cerebrospinal fluid was 0.39 microg/ml for cefotaxime and 0.78 microg/ml for desacetylcefotaxime. The extraction recovery from cerebrospinal fluid spiked with cefotaxime and desacetylcefotaxime was 90.4-100.1% and 97.4-102.9%, respectively. The RSDs were below 10.7% for cefotaxime and 6.8% for desacetylcefotaxime. The developed SPE-HPLC method was applied for cefotaxime and desacetylcefotaxime determination in cerebrospinal fluid of children with hydrocephalus after intraventricular administration.