title: Determination of apalcillin and its metabolites in human body fluids by high-pressure liquid chromatography.
abstract: We describe two methods for the quantitative analysis of apalcillin and its metabolites in serum and urine by reverse-phase high-pressure liquid chromatography (HPLC), a fast isocratic method for the parent drug, and a gradient method that allows the simultaneous assay of two metabolites. Serum was deproteinized with acetonitrile, and urine was diluted with buffer solution. The detection limit was about 0.5 micrograms/ml at a detection wavelength of 254 nm and 1.5 micrograms/ml at 310 nm. Within-batch precision (coefficient of variation) varied from 10.2 to 1.1% for concentrations of 7.8 and 185.3 micrograms/ml of serum, respectively. Recovery rates of 95.1 and 97.7% were found in spiked sera. Results obtained by HPLC correlated well with those from a standard microbiological assay (agar diffusion test); the resulting bivariate regression equation for serum was y-bioassay = 2.5 micrograms/ml + 0.992 X xHPLC, and that for urine was ybioassay = 12.0 micrograms/ml + 1.009 X xHPLC. At a detection wavelength of 315 nm, no interferences were observed in 10 healthy volunteers. Healthy subjects who were given 2 g of apalcillin intravenously excreted 18% of the parent drug within 24 h in the urine. Two inactive compounds were furthermore identified in urine as the isomeric forms of the penicilloic acids. Their excretion within 24 h amounted to 6.9 and 11.2% of the dose.
mesh_terms: D000667:Ampicillin / Q000031:analogs & derivatives* / Q000032:analysis / Q000652:urine; D001412:Bacillus subtilis / Q000187:drug effects; D001681:Biological Assay; D001711:Biotransformation; D001826:Body Fluids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D009287:Naphthyridines; D012505:Sarcina / Q000187:drug effects
chemical_list: D009287:Naphthyridines; C012122:apalcillin; D000667:Ampicillin