Study of the physicochemical properties of the etravirine substance

Introduction. Etravirine, being one of the most popular antiretroviral drugs, doesn't have its physicochemical properties sufficiently described in scientific publications. Detailed information on the substance properties is necessary both for organizing the synthesis and for justifying the dosage form and technology for its production, as well as for identifying bottlenecks and critical parameters that affect the quality of the finished product. Aim. Study the etravirine physicochemical properties to model the design of studies to create an innovative dosage form Materials and methods . Etravirine (MSN Life Sciences Pvt. Ltd., Hetero Labs Ltd.). The melting point was determined by the capillary method. Etravirine samples were studied via differential scanning calorimetry (DSC), X-ray powder diffractometry, IR and NMR spectroscopy. Particle size was determined using laser diffraction analysis. The shape and size of the crystals were determined with the help of transmission electron microscopy (TEM). The concentration of etravirine in aqueous media was determined using the HPLC method with a fluorescence detector. The concentration of etravirine in organic solvents was determined spectrophotometrically. Results and discussion . The X-ray powder diffractometry and IR spectroscopy helped to determine the fact that the studied substances represent the same polymorphic modification. The melting point of etravirine ranges from 259 to 263 °C. Melting is accompanied by decomposition. The substance is practically insoluble in aqueous media at pH values in the range from 1.2 to 6.8, soluble in some organic solvents, readily soluble in dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, dimethylacetamide. The distribution coefficient in the "1-octanol/phosphate buffer solution pH 6.8" solvent system was 5.22. The experiment showed that the etravirine substance is lipophilic. Etravirine is found to be a highly crystalline substance and represents needle-shape prismatic crystals. Conclusion. Etravirine is a lipophilic substance, practically insoluble in aqueous solutions, soluble in a number of organic solvents. The studied substances turned out to be the same polymorphic modification. Since the melting of the substance is accompanied by decomposition, high temperatures processes should be avoided. Conflict of interest. The authors declare that they have no obvious and potential conflicts of interest related to the publication of this article.