Stability-Oriented RP-HPLC Method Development for Simultaneous Quantification of Azelnidipine and Telmisartan in Pharmaceutical Dosage Forms

Abstract

A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for simultaneous quantification of Azelnidipine (AZN) and Telmisartan (TMN) in combined tablet dosage forms. Chromatographic separation was achieved using a C18 column (100 × 4.6 mm, 2.5 µm particle size) with a mobile phase consisting of Acetonitrile: pH 3 phosphate buffer (75:25, v/v) at a flow rate of 0.9 mL/min, with detection occurring at 237 nm.

The method was validated according to International Conference on Harmonisation (ICH) guidelines, demonstrating linearity over the concentration ranges of 6.4-32 µg/mL for AZN and 16-80 µg/mL for TMN. The limits of detection (LOD) and quantitation (LOQ) were determined to be 0.4399 and 1.3332 for AZN, and 0.882 and 2.6729 for TMN, respectively. The method also exhibited precision, repeatability, and accuracy, with relative standard deviations (RSD) ≤ 2% and accuracy ranging from 99-101%.

To assess the method's stability-indicating capability, forced degradation studies were conducted under four stress conditions: acidic hydrolysis, alkaline hydrolysis, oxidative degradation, and thermal degradation. The results confirmed the method's ability to accurately quantify AZN and TMN in the presence of degradation products.