IDENTIFICATION AND QUANTITATIVE DETERMINATION OF SILDENAFIL BY CHROMATOSPECTROPHOTOMETRIC METHOD

569 Volume 5, Issue 10: Special Issue (EJAR) ISSN: 2181-2020 MPHAPP THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “MODERN PHARMACEUTICS: ACTUAL PROBLEMS AND PROSPECTS” TASHKENT, OCTOBER 17, 2025 in-academy.uz IDENTIFICATION AND QUANTITATIVE DETERMINATION OF SILDENAFIL BY CHROMATOSPECTROPHOTOMETRIC METHOD Mukhamedova D.Sh. Sultanova A.A. Tashkent Pharmaceutical Institute, Tashkent, Republic of Uzbekistan e-mail: [email protected] https://doi.org/10.5281/zenodo.17344459 Relevance. Sildenafil is a potent inhibitor of phosphodiesterase type 5, widely used in the treatment of erectile dysfunction. In recent years, there has been an increase in its use among underage adolescents, as well as its combination with potent psychoactive substances in order to prolong their effects. Such practices negatively impact the developing body and are accompanied by pronounced side effects, including headaches, facial flushing, nasal congestion, dyspeptic disorders, chest pain, shortness of breath, visual disturbances, and tachycardia. In cases of severe poisoning, stroke, myocardial infarction, and sudden cardiac death are possible. Given the widespread use of sildenafil and the potential risks of its abuse, the development of reliable methods for its identification is a relevant task in forensic chemical practice. One such method is the use of chromatographicspectrophotometric techniques. Objective of the study. The aim of this study is the identification and quantitative determination of sildenafil using the chromatographic-spectrophotometric method. Materials and Methods. Five chromatographic plates coated with "Silica gel" sorbent were prepared for analysis. The plates were dried in a special drying oven. Each plate was divided horizontally into two parts: 0.3 ml of a 0.1% standard ethanol solution of sildenafil was applied to one part, while 1 ml of the same solution was applied along the starting line of the second part. After application, the plates were air-dried at room temperature. Then, all plates were placed into chromatographic chambers containing a mobile phase composed of acetonitrile, ethyl acetate, and 10% ammonium hydroxide solution in a ratio of 5:4:1. After the solvent front had risen to 10 cm, the plates were removed and dried at room temperature. To detect the sildenafil zone, the first part was treated with Dragendorff's reagent. The corresponding area of the sorbent containing sildenafil from the opposite part was scraped off with a scalpel and eluted with 95% ethanol. The resulting solutions were filtered through filter paper, the volume was adjusted to 10 ml, and analyzed using a UV-spectrophotometer (UB-Spectroscopy System by Agilent Technologies, model 8453E), using 10 mm path length cuvettes at a wavelength of 230 nm. The quantitative content of sildenafil was determined by UV-spectrophotometric method. The above-mentioned studies were also conducted using chromatographic plates containing aluminum oxide, and ready-made plates of the VWR TLC ALUMINIUM PLATES brand coated with F254 silica gel. The study showed that chromatographic plates made with aluminum oxide are not suitable for determining sildenafil using thin-layer chromatography. The VWR TLC ALUMINIUM PLATES coated with F254 silica gel were found to be practical for identifying sildenafil using a UV lamp, without the need for additional chemical reagents. Results. According to the results of the quantitative analysis, the average content of sildenafil was 94.8%, with a relative error of 1.93%. Conclusion. The obtained data demonstrate that the developed method can be used in forensic chemical and toxicological practice for the identification and quantitative determination of sildenafil.