Quantitative determination of thalidomide in human serum with high-performance liquid chromatography using protein precipitation with trichloroaceticacid and ultraviolet detection

A validated and precise reversed-phase high-performance liquid chromatograp hic method for the determination of thalidomide in serum, with phenacetin a s an internal standard, is described. Protein precipitation, using trichlor oacetic acid, was used for clean-up. The aliquot was chromatographed on a o ctadecyl column, using an eluent composed of 250 ml 0.01 M potassium dihydr ogenphosphate, adjusted to a pH of 3.0 with a 43% phosphoric acid solution, mixed with 750 ml methanol. Ultraviolet detection was used at an operation wavelength of 220 nm. Hydrolytic degradation was prevented during analysis by acidification of samples with the precipitation reagent. Thalidomide an d phenacetin were found to have retention times of 7.9 and 15.0 min, respec tively. Recoveries ranging from 79 to 84% were found for both components, w ith reproducibility relative standard deviations of 0.8-3% and repeatabilit y coefficients of 1.2-3%. A mean correlation coefficient of 0.9995 was foun d for the linear calibration curve (n=2) of thalidomide with Limits of quan titation of 0.222-21 mg/l. The method appeared to be feasible for pharmacok inetic studies with thalidomide. (C) 1999 Elsevier Science B.V. All rights reserved.