HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR MEROPENEM IN SERUM

High-performance liquid chromatographic procedures have been developed for the measurement of meropenem in serum. The separation was perform ed on an Ultrasphere XL-ODS analytical column (75X4.6 mm I.D.). The mo bile phase consisted of 10.53 mmol/l ammonium acetate-acetonitrile (95 :5, v/v) (pH 4). The UV detection was at 298 nm. The quantitation limi t both in serum and water was 0.25 mu g/ml. The method was validated i n serum and aqueous solution over the concentration range 0.25-50 mu g /ml. The extraction recovery from serum spiked with meropenem was 99.7 +/-3.4%. The intra- and inter-assay coefficients of variation were bel ow 6%. Stored at -80 degrees C for three months at various concentrati ons in serum and in aqueous solution, meropenem did not reveal any app reciable degradation. After 24(-)h, it was also stable at 4 degrees C in serum, aqueous solution and supernatant of extraction but not at ro om temperature. The stability of the drug was also confirmed in serum after repeated freezing-thawing cycles at -80 degrees C on four consec utive days.