DETERMINATION OF THE QUANTITATIVE CONTENT OF EFAVIRENZ BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH AN ULTRAVIOLET DETECTOR
This article is the result of the development of a method for the quantitative determination of efavirenz using high-performance liquid chromatography (HPLC) in medicinal products. To achieve optimal system suitability parameters, data were analyzed with using more than 10 chromatographic columns under different chromatographic conditions. Available literature has been analyzed too, including from foreign sources of information. The best result is achieved when using the Zorbax SB-CN chromatographic column, a silica column chemically modified with nitrile groups. it is characterized by good efficiency, stability to aggressive media conditions, and thermal stability. The advantages of the developed method are the speed, unambiguity of the results and the range of application (from 5 % to 130 % of the expected concentration of the target substances in the solution). This wide range of concentration values makes it possible to use this technique both for studying the dissolution kinetics and for conducting a comparative dissolution kinetics test, and for determining the maximum permissible levels of contamination of production equipment (PDUZ) and wastewater. This proves that the developed method is suitable for solving various problems of pharmaceutical production. In addition, it meets the requirements of modern chromatographic analysis-speed and efficiency. During the preparation of the article, the necessary studies were carried out to confirm the validity of the method, and all the main requirements of the state Pharmacopoeia of the Russian Federation were taken into account. The chromatograms given in the article prove the selectivity of the method. The standard deviation of the efavirenz peak areas, the relative standard deviation for 5 chromatograms of the standard solution, and the correlation coefficient proving the linearity of the method were calculated. In addition, an analysis of the precision (convergence and intra-laboratory precision) of the analytical technique was performed, and a statistical evaluation was performed using the Fisher F-test and the student t-test. The efficiency of this method is characterized by the following parameters: the peak asymmetry factor, the number of theoretical plates (CHT) and the relative standard deviation. Based on the data obtained, a conclusion was made about the efficiency of the method.