Determination of fosfomycin in chicken plasma samples by gas chromatography:: Application to pharmacokinetic studies

A sensitive gas chromatographic method is described for the analysis of fosfomycin (FOS) in chicken plasma using phenylphosphonic acid (PPA) as the internal standard. Plasma samples were ultrafiltered, and the ultrafiltrate was then evaporated to dryness. The residue was reconstituted with a silylation reagent for the derivatization of FOS and PPA. The methodology involves the use of a HP-5 capillary column and a flame ionisation defector (FID). The retention times of FOS and PPA were 4.63 and 8.68 minutes, respectively. Response was linear in the range of 1 - 150 mug mL(-1). The detection and quantitation limits were 1 and 2.1 mug mL(-1), respectively. Recovery was determined as 109% for FOS. The method was applied to the determination of FOS in chicken plasma samples collected during pharmacokinetic studies.