eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2026-03-30 23 1 280 293 10.13005/bbra/3497 58408 article Deepali Dattatray Bhandari 1 Charushila Jayant Bhangale 3 Santosh Ranganath Tambe 1 Sunil Vishwanath Amrutkar 2 Department of Pharmaceutical Chemistry, Mahatma Gandhi Vidyamandir’s Pharmacy College, Panchvati, Nashik, India. Department of Pharmaceutical Chemistry, GES’s Sir Dr. M. S. Gosavi College of Pharmaceutical Education and Research, Nashik, India. Department of Pharmaceutical Chemistry, PRES’s, College of Pharmacy (For Women), Chincholi, Sinnar, Nashik, India. Hypertension is treated with a combination of Telmisartan (TLM) and Azelnidipine (AZD). The purpose of the study was to ascertain TLM/AZD's bioavailability and bioequivalency in human plasma. For the best extraction of TLM and AZD from the biological matrix, the solid phase extraction method was developed. Chromatographic separation using an Inertsil C18 column (4.0 mm x 250 mm, 5 µm) and a 50 mM mobile phase were employed in the process. At a flow rate of 1.0 mL/min and an injection volume of 20 μL, acetic acid (Component A) and acetonitrile (Component B) were used in a 30:70 v/v ratio to modify the pH of ammonium acetate to 4.5. TLM and AZD in plasma were quantified by UV detection at 240 nm, with retention periods of 7.33 and 11.32 minutes, respectively. The method was verified using recovery experiments and statistical analysis, demonstrating a linearity concentration range of 50 ng/mL to 2000 ng/mL and coefficient of determination (R²) for both the drugs has been found to be 0.9998. Analysis of six replicate samples at five quality control levels (LLOQ, LQC, MQC, HQC, and ULOQ) were done to evaluate accuracy and precision both within and between days. The results showed values that were within 99–103% for each level of both the drugs. Consistent extraction recoveries of 89–93% across all quality control levels met regulatory acceptance criteria, demonstrating efficient and reproducible sample preparation.  According to stability studies both medications were stable during benchtop, freeze-thaw, autosampler, refrigeration (2–8 °C), and long-term storage conditions. The technique turned out to be quick, accurate, straightforward, and precise, yielding valuable information for pharmacokinetics research and therapeutic medication monitoring in clinical labs. https://www.biotech-asia.org/vol23no1/development-and-validation-of-rp-hplc-bioanalytical-method-for-simultaneous-estimation-of-azelnidipine-and-telmisartan-in-human-plasma/ Azelnidipine; Bioanalytical Method Development; Human Plasma; ICH; RP-HPLC; Telmisartan