DETERMINATION OF A NEW FLUOROQUINOLONE ANTIMICROBIAL AGENT, O-7H-PYRIDO[L,2,3-DE][1,4]BENSOXAZINE-6-CARBOXYLIC ACID HEMIHYDRATE, DV-7751A, IN HUMAN SERUM AND URINE USING SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A high-performance liquid chromatographic method for the determination of a new fluoroquinolone antimicrobial agent, o-7H-pyrido[1,2,3-de][1 ,4]benzoxazine-6-carboxylic acid hemihydrate (DV-7751a, I) in human se rum and urine has been developed. Compound I and the internal standard were extracted from serum and urine by means of Bond Elut C-8 LRC col umn. The extracts were chromatographed on a reversed-phase Inertsil OD S-2 column using tetrahydrofuran-50 mM KH2PO4 (pH 2)-1 M ammonium acet ate (19:81:1, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. F luorescence detection at an excitation wavelength of 305 nm and an emi ssion wavelength of 530 nm resulted in a limit of quantitation of 0.00 98 mu g/ml for serum and 0.098 mu g/ml for urine. The method showed sa tisfactory sensitivity, precision, accuracy, recovery and selectivity. Stability studies showed that I was stable in serum and urine for at least 1 month at -20 degrees C and for at least 48 h at room temperatu re.