A high performance liquid chromatography method for the determination of FCE 22101, a novel penem antimicrobial, in serum.

FCE 22101 (sodium [5R, 6S, 8R]-6-alpha-hydroxyethyl-2-carbamoyloxymethyl-2- penem-3-carboxylate) is a new penem antimicrobial with a broad spectrum of activity. In order to investigate the pharmacokinetics of FCE 22101 in human volunteers, a high performance liquid chromatographic assay has been developed for determining concentrations of FCE 22101 in serum. Serum samples were deproteinised with an equal volume of acetonitrile followed by centrifugation. The supernatant was then diluted with an equal volume of 0.05 M phosphate buffer (pH 7.0) and 50 microliters was applied to the separation column. Chromatographic separation of FCE 22101 was achieved using an SP8700 solvent delivery system (Spectra-Physics), an SP8780XR autosampler (Spectra-Physics) and a reverse-phase C18 mu-BondaPak column (8 X 100 mm) radially compressed in a Z module (Millipore, UK). The mobile phase consisted of a water, methanol and orthophosphoric acid mixture (74:25:1), which was filtered through a 0.22 micron filter and de-gassed under vacuum prior to use. The flow rate was 1.4 ml/min and FCE 22101 was detected in the column eluant using an LC871 UV-Vis detector set at 318 nm. The data were analysed using an SP4270 integrator (Spectra-Physics). The lower limit of sensitivity of the assay method was 0.8 mg/l and recovery from deproteinised serum was of the order of 70%. Intra-assay variation was less than 5% and inter-assay variation was less than 10%.