DETERMINATION OF MEROPENEM IN PLASMA BY HIGHPERFORMANCE LIQUID-CHROMATOGRAPHY AND A MICROBIOLOGICAL METHOD

A rapid and selective high-performance liquid chromatographic (HPLC) m ethod for the quantitative determination of meropenem in plasma is des cribed. The drug was separated from plasma after plasma protein precip itation with 15% of trichloroacetic acid. The mobile phase consisted o f acetonitrile-water-glacial acetic acid (21.2, 78 and 0.8% v/v, respe ctively) delivered at a flow rate of 1.2 ml/min. Meropenem was quantif ied using ultraviolet detection at 296 nn. Meropenem and the internal standard (pheniramine) were well separated from plasma components. The drug could be assayed by the HPLC method in the presence of its analo gue, imipenem. The detection limit in plasma was 25 ng/ml of meropenem . The results were compared with those of agar for a microbiological d iffusion method using Escherichia coli ATCC 25922 as the test organism . The sensitivity of the microbiological assay was less than 5 ng/ml, but this decreased at higher concentrations. Both methods were applied to the determination of the drug in aqueous solutions and in plasma.