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.
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机译：我们描述了两种通过反相高压液相色谱（HPLC）定量分析血清和尿液中阿帕西林及其代谢物的方法，一种母体药物的快速等度法和一种允许同时检测两种方法的梯度法代谢产物。用乙腈使血清脱蛋白，并用缓冲液稀释尿液。在254nm的检测波长下的检测极限为约0.5微克/ ml，在310nm下的检测极限为1.5微克/ ml。血清浓度分别为7.8和185.3微克/毫升时，批内精密度（变异系数）从10.2％到1.1％不等。掺入血清中的回收率分别为95.1和97.7％。高效液相色谱法获得的结果与标准微生物测定（琼脂扩散试验）的结果具有很好的相关性；血清的二元回归方程为y-生物测定= 2.5微克/ ml + 0.992 X xHPLC，尿液的二元回归方程为ybioassay = 12.0微克/ ml + 1.009 X xHPLC。在315 nm的检测波长下，在10名健康志愿者中未观察到干扰。服用2 g阿帕西林静脉注射的健康受试者在24小时内尿液中排泄了18％的母体药物。此外在尿液中鉴定出两种非活性化合物为青霉酸的异构形式。它们在24小时内的排泄量为剂量的6.9和11.2％。
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