Determination of ceftazidime in plasma using high-performance liquid chromatography and electrochemical detection - Application for individualizing dosage regimens in elderly patients

This study describes a sensitive HPLC-electrochemical detection method for the analysis of ceftazidime, a third-generation cephalosporin, in human plasma. The extraction procedure involved protein precipitation with 30% trichloroacetic acid. The separation was achieved on a reversed-phase column (250X4.6 mm I.D., 5 mu m) packed with C-18 Kromasil with isocratic elution and a mobile phase consisting of acetonitrile-25 mM KH2PO4-Na2HPO4 buffer, pH 7.4 (10:90, v/v). The proposed analytical method is selective, reproducible and reliable. The assay has a precision of 0.2-15.1% (C.V.) in the range of 5-200 mu g ml(-1) (corresponding to 0.5 to 20 ng of ceftazidime injected onto the column), and is optimised for assaying 50 mu l of plasma. The extraction recovery from plasma was approximately 100%. The method was highly specific for ceftazidime and there was no interference from either commonly administered drugs or endogenous compounds. This assay was used to measure ceftazidime in elderly patients for therapeutic drug monitoring. (C) 1998 Published by Elsevier Science B.V. All rights reserved.