Eco-friendly chromatographic platforms for simultaneous determination and impurity profiling of an antihypertensive ternary pharmaceutical mixture

Abstract

Development of new analytical methods that are capable of determining pharmaceutically active substances in the presence of their related impurities is vital in pharmaceutical industry. Herein, simple, reliable and ecofriendly chromatographic methods were established, optimized and validated for the concurrent estimation of amiloride hydrochloride (AML), hydrochlorothiazide (HCT) and timolol maleate (TIM) along with hydrochlorothiazide potential impurities, salamide (DSA) and chlorothiazide (CT). The first established method was based on high performance liquid chromatography (HPLC-DAD). Separation was achieved using XBridge C18 analytical column and a gradient elution system comprises solvent A [20.0 mM phosphate buffer (pH = 3)] and solvent B [acetonitrile]. UV detection was accomplished at 220.0 nm for AML, HCT and HCT related impurities and at 295.0 nm for TIM. The second method was a LC-MS/MS method for the profiling and quantification of HCT impurities (DSA and CT). Separation was executed on Agilent Poroshell 120 EC-C18 column using mobile phase consisted of methanol and 0.1% formic acid in a ratio of 97:3 (v/v) pumped at flow rate of 0.7 mL/min with a run time of 3.0 min. Impurities were quantified via the utilization of multiple reaction monitoring mode (MRM) and triple quadrupole mass detection with electrospray ionization. The method demonstrated excellent sensitivity and linearity with limit of detection (LOD) of 1.0 ng/mL and 0.1 ng/mL for DSA and CT, respectively. Validation of the suggested methods was achieved in compliance with the ICH guidelines and were successively utilized for the determination of the aformentioned compounds in Moducren® tablets. Additionally, the advantage of the developed HPLC-DAD method was extrapolated for in-vitro drug release monitoring. Greenness of the proposed methods was assessed using different well established assessment tools.