Determination of a new fluoroquinolone antimicrobial agent, (S)-10-[(S)-(8-amino-6-azaspiro d3,4]octan-6-yl)]-9-fluoro-2, 3-dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine-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, (S)-10-[(S)-(8-amino-6-azaspiro[3,4]octan-6-yl)]-9-fluoro-2,3- dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid hemihydrate (DV-7751a, I) in human serum and urine has been developed. Compound I and the internal standard were extracted from serum and urine by means of Bond Elut C8 LRC column. The extracts were chromatographed on a reversed-phase Inertsil ODS-2 column using tetrahydrofuran-50 mM KH2PO4 (pH2)-1 M ammonium acetate (19:81:1, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. Fluorescence detection at an excitation wavelength of 305 nm and an emission wavelength of 530 nm resulted in a limit of quantitation of 0.0098 microgram/ml for serum and 0.098 microgram/ml for urine. The method showed satisfactory 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 temperature.