High-performance liquid chromatographic methods for the determination of anew carbapenem antibiotic, L-749,345, in human plasma and urine

A column-switching, reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of a new carbapenem antibiotic assay us ing ultraviolet detection has been developed for a new carbapenem antibioti c L-749,345 in human plasma and urine. A plasma sample is centrifuged and t hen injected onto an extraction column using 25 mM phosphate buffer, pH 6.5 . After 3 min, using a column-switching valve, the analyte is back-flushed with 10.5% methanol-phosphate buffer for 3 min onto a Hypersil 5 mu m C-18 BDS 100X4.6 mm analytical column and then detected by absorbance at 300 nm. The sample preparation and HPLC conditions for the urine assay are similar , except for a longer analytical column 150X4.6 mm. The plasma assay is spe cific and linear from 0.125 to 50 mu g/ml; the urine assay is linear from 1 .25 to 100 mu g/ml. (C) 1998 Published by Elsevier Science B.V. All rights reserved.