HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR CEFEPIME IN SERUM

A simple, rapid, specific and sensitive high-performance liquid chroma tographic method was developed for the determination of cefepime 1-[[( 6R, [4.2.0]oct-2-en-3-yl]methyl]-1-methylpyrrolidinium hydroxide, inne r salt, 7(2)-(Z)-(O-methyloxime) in human serum. Separation was achiev ed on a reversed-phase Ultrasphere XL-ODS column (75x4.6 mm I.D.). The mobile phase was 7% acetonitrile in 20 mM ammonium acetate (pH 4). Ce fepime eluted in the range of 1.8-2.2 min. Detection was by UV absorba nce at 254 nm. The lower limit of quantitation of cefepime in plasma w as 0.5 mu g/ml. The average absolute recovery was 106.2+/-2.1%. The li near range was from 0.1 to 50 mu g/ml, with a correlation coefficient greater than 0.999. The within-day C.V.s for human samples were 4.9 an d 2.3% for 1 and 50 mu g/ml, respectively. The between-day C.V.s for h uman serum samples were 14.5, 7.4 and 6.7 for 1, 25 and 50 mu g/ml, re spectively. Cefepime was found to be unstable in serum at room tempera ture. For delayed assay, samples must be stored at -80 degrees C.