Allopurinol is used as a uricosuric agent and a potential compound for impurity profile study. In the present work, a simple and validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for determination of process impurities and degradation products of allopurinol in bulk drug and pharmaceutical formulations. This method involves the use of the C₁₈ (ODS C₁₈, 250 x 4.6 mm, 5 mm) column. The mobile phase consisted of a mixture of 0.1 M dipotassium phosphate buffer (pH 3.5) and acetonitrile in the ratio of 55:45 v/v. The flow rate was set at 1.5 ml/ min with UV detection at 254 nm. The drug was subjected to different ICH prescribed stress conditions like hydrolysis (acidic, alkaline and neutral medium), oxidation, photolysis, and thermal degradation. The developed method was validated for linearity, accuracy, precision, selectivity and specificity. Accuracy was determined by mixing the allopurinol tablet solution with known impurities. Excellent recoveries of impurities A, B, and C proved that the method was sufficiently accurate. This validated developed method can be conveniently used in the quality control laboratory for routine analysis of the drug and its related substances and for the analysis of stability samples of drug in bulk drug and pharmaceutical formulations.

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