development of a reversed-phase hplc method for determination of related impurities of lenalidomide

in this project, we have developed a reversed phase liquid chromatography method for separation and determination of lenalidomide (lena) and related substances by using c-8 (250×4.6 mm id, 5 μm) hpcl column. the mobile phases a and b were phosphate buffer at ph=3.30, and (methanol:acetonitrile)(1:5 v/v), respectively. the column oven temperature was 25°c, the wavelength was 220nm, and the injection volume was 20 μl. the degradation studies using basic, acidic, oxidation, and thermal stress, were performed. in addition, in the basic stress, a significant degradation for lena, was observed.

the results showed that the resolutions of the peaks for fresh, acid stress, and thermal stress were considerably high. for example, in the case of thermal shock, the resolution of each peak to the next, was 3.6, 3.2, 5.3, and 4.7. thus, it indicates that the method is suitable at least in view of separation and resolution for the peaks produced by thermal shock.