Liquid chromatography-tandem mass spectrometry for quantification of cefaclor in rat plasma and its application to pharmacokinetic studies

Abstract

A simple and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) in the positiveelectrospray ionization mode was developed and validatedin order to analyze cefaclor, a second generation cephalosporinantibiotic, in rat plasma. The plasma was pre-treatedby a single step of protein precipitation with methanol, andthen injected directly into the LC/MS/MS system forquantification. Drugs were separated on a Synergi 4lPolar-RP 80 A column (150 9 2.0 mm) with a mixture of0.1 % formic acid and methanol (65 : 35, v/v) as the mobilephase at 0.2 mL/min. Detection was performed with multiplereaction-monitoring modes at m/z 368.1 ? 174.2 (forcefaclor) and m/z 396.0 ? 227.1 (for cefdinir, the internalstandard). The limit of quantification (LOQ) was determinedto be 10 ng/mL with acceptable linearity rangingfrom 10 to 10,000 ng/mL. Validation parameters for cefaclor,including accuracy, precision, absolute matrix effect,and stability in rat plasma, were acceptable according tothe assay validation guidelines of the FDA (U.S. Departmentof Health & Human Services, Food and DrugAdministration, Guidance for Industry, BioanalyticalMethod Validation, 2001). The developed analyticalmethod was successfully applied to the pharmacokineticstudies of cefaclor in rats. These observations suggest,therefore, that the validated assay can be used in routinepharmacokinetic studies of cefaclor in rats.