_1684139116 20230515082516000 Editor editor.jddt@gmail.com Universal Journal of Pharmaceutical Research Universal Journal of Pharmaceutical Research Univ J Pharm Res 2456-8058 2831-5235 05 15 2023 A. Hakan AKTAŞ https://orcid.org/0000-0003-2327-4031 Hülya SARI https://orcid.org/0000-0002-9331-7810 Background: As it is known, antihypertensive drugs are frequently used for the treatment of individuals with high blood pressure all over the world. This study aims is to precisely determine the active substances of telmisartan and hydrochlorothiazide, which are commercially sold as high blood pressure drugs in the market, and to use the ratio spectrum method for this purpose. Method: All, solutions of the active ingredients of the drugs studied in the method were prepared in various concentrations. Subsequently, mixtures were prepared in accordance with the commercial drug sample, their spectra were taken by spectrophotometric method, and the spectrum ratio method was successfully applied to these data sets. Results: The study revealed that the application of the ratio spectra first-order derivative spectrophotometric method yielded highly reliable outcomes in the spectrophotometric analysis of different combinations of telmisartan and hydrochlorothiazide. Conclusion: The applied method can be used in the field of drug development.                        Peer Review History: Received: 25 February 2023; Revised: 8 March; Accepted: 13 April 2023, Available online: 15 May 2023 Academic Editor: Dr. Sally A. El-Zahaby, Pharos University in Alexandria, Egypt, sally.elzahaby@yahoo.com Received file:                             Reviewer's Comments: Average Peer review marks at initial stage: 5.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Prof. Cyprian Ogbonna ONYEJI, Obafemi Awolowo University, Ile-Ife, Nigeria, conyeji@oauife.edu.ng Dr. Wafa Mohamed Al Madhagi, Sana’a University, Yemen, walmadhaji1983@gmail.com 05 15 2023 http://creativecommons.org/licenses/by-nc/4.0 10.22270/ujpr.v8i2.924 https://ujpr.org/index.php/journal/article/view/924 https://ujpr.org/index.php/journal/article/download/924/1381 https://ujpr.org/index.php/journal/article/download/924/1381 https://ujpr.org/index.php/journal/article/download/924/1391 https://ujpr.org/index.php/journal/article/download/924/1404