DEVELOPMENT OF A RAPID AND EFFICIENT METHOD FOR QUANTITATIVE DETERMINATION OF N-NITROSODIMETHYLAMINE IMPURITY BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY IN METFORMIN HYDROCHLORIDE, LOSARTAN POTASSIUM, VALSARTAN AND RANITIDINE MEDICINAL RAW MATERIALS AND ITS PRODUCTS. Proceedings of the YSU B: Chemical and Biological Sciences, v. 55, n. 3 (256), p. 296–299, 23 Dec.2021.