RESUMO
OBJECTIVE: To establish the International Pharmacopoeia standard for norethisterone tablets. METHODS: In accordance with the requirements of the International Pharmacopoeia standard, the existent quality standards of norethisterone tablets and related literatures were referred, appropriate methods were selected, and verification test was carried out to determine the best method. RESULTS: In the system suitability test of thin layer chromatography identification, the spots of norethisterone and ethinylestradiol were separated well. Nine known impurities and other unknown impurities could be separated well by the HPLC method for the examination of related substances, and the impurity with relative retention time of 1.1 was shown to be ethinylestradiol by LC-MS. In 0.1 mol·L-1 hydrochloric acid solution containing 0.09% SDS, norethisterone tablets achieved a dissolution of more than 90% in 30 min and the dissolution curve reached plateau. Under the liquid chromatographic condition for the assay, the linear range was 0.746-29.840 μg·mL-1 (r=0.999 9), and the resolution between norethisterone and ethinylestradiol was over 4.0. CONCLUSION: The established quality standard of norethisterone tablets is simple and accurate, which fully considers the feasibility of the method and accessibility of reagents, thus can effectively control the quality of products.