Yost R L, Derendorf H
J Chromatogr. 1985 May 31;341(1):131-8. doi: 10.1016/s0378-4347(00)84017-7.
A reversed-phase high-performance liquid chromatographic assay for the simultaneous determination of cefotaxime and its metabolite desacetylcefotaxime in plasma and urine was developed. Plasma was deproteinized with small amounts of acetonitrile. After separation of the proteins the supernatant was extracted with a mixture of chloroform and 1-butanol. A phase separation was obtained leaving the cephalosporin and its metabolite in the aqueous part and extracting most of the interfering endogenous material. The aqueous phase was injected directly into the chromatograph. As part of the plasma water was dissolved in the acetonitrile--1-butanol--chloroform layer, the concentration of the cephalosporin in the aqueous phase was significantly higher than in the original plasma sample. Therefore, the usual diluting effect of the deproteinization could be avoided. In a similar way the assay was applicable to measure cefotaxime and its metabolite in urine. Calibration curves were set up and were linear up to 25 micrograms/ml for desacetylcefotaxime and 250 micrograms/ml for cefotaxime. The assay was applied to study the pharmacokinetics of cefotaxime and its metabolite in a healthy volunteer. In a similar way this deproteinization and extraction method was also applied to assay for ceftazidime, cephalexin, cephazolin and cefoxitin.
建立了一种反相高效液相色谱法，用于同时测定血浆和尿液中的头孢噻肟及其代谢产物去乙酰头孢噻肟。用少量乙腈使血浆脱蛋白。蛋白质分离后，上清液用氯仿和1-丁醇的混合物萃取。实现了相分离，使头孢菌素及其代谢产物留在水相中，并萃取出大部分干扰性内源性物质。水相直接注入色谱仪。由于部分血浆水溶解在乙腈-1-丁醇-氯仿层中，水相中头孢菌素的浓度明显高于原始血浆样品。因此，可以避免通常的脱蛋白稀释效应。以类似的方式，该测定法适用于测量尿液中的头孢噻肟及其代谢产物。建立了校准曲线，去乙酰头孢噻肟在高达25微克/毫升时呈线性，头孢噻肟在高达250微克/毫升时呈线性。该测定法用于研究健康志愿者体内头孢噻肟及其代谢产物的药代动力学。以类似的方式，这种脱蛋白和萃取方法也用于测定头孢他啶、头孢氨苄、头孢唑林和头孢西丁。
