STABILITY-INDICATING ASSAY FOR AZATHIOPRINE AND 6-MERCAPTOPURINE BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A rapid method based on reversed-phase high-performance liquid chromatography is described for the separation and quantitation of azathioprine, 6-mercaptopurine and their potential contaminants and degradants present in dosage forms. Procedures based on simple dissolution or extraction in 0.02 M NaOH give quantitative precision of 1 % relative standard deviation at the macro-level and 2 % relative standard deviation for the micro-assay of analytes. The method is stability-indicating and has been used for preliminary studies of the degradation of azathiorine in 0.9 % sodium chloride injection, subjected to thermal or ultraviolet irradiation treatment. The content uniformity of dosage forms of azathioprine and 6-mercaptopurine has been measured Only azathioprine injection as the freeze-dried sodium salt ws found to contain detectable amounts of contaminants 6-mercaptopurine, 1-methyl-4-nitro-5-chloroimidazole and hypoxanthine. © 1979.