Green micellar liquid chromatographic analysis of alfuzosin hydrochloride and sildenafil citrate in a binary mixture compared to classical RPLC with stability indicating studies.

Two simple and validated chromatographic studies were performed for simultaneous estimation of sildenafil citrate (SIL) and alfuzosin hydrochloride (ALF) in bulk, pharmaceuticals, and in the presence of their main degradation products. Two systems of mobile phase were applied isocratically for their first chromatographic separation using conventional and micellar mobile phases. Methanol, acetonitrile, and 0.02 M potassium dihydrogen phosphate (43:14:43 v/v; pH 4.66) were pumped at 1.3 mL/min in method I. Meanwhile, method II was based on less hazardous micellar mobile phase of nonionic surfactant (0.005 M Brij-35 in water; pH 2.5 adjusted with 0.1% orthophosphoric acid) with a flow rate of 1 mL/min. Both methods were carried on C18 column and coupled with UV detection at 225 nm at ambient temperature. The first method was rectilinear over the concentration range of 5-62.5 µg/mL for both drugs, while the second method showed higher linearity ranges of 0.5-40, 2.5-62.5 µg/mL for ALF and (SIL), respectively. The developed methods successfully enabled the quantification of the studied binary mixture in their tablets dosage form and evaluation their stabilities. Validation of the proposed methods according to ICH guidelines and system suitability were ascertained. Moreover, the applied methods were evaluated and compared from the perspective of green analytical chemistry, employing the National Environmental Methods Index, analytical Eco-Scale score, and Green Analytical Procedure Index, as three assessment tools.

Development of green differential pulse voltammetric strategy for the determination of alfuzosin hydrochloride at pencil graphite and modified carbon paste electrodes.

A sensitive and inexpensive differential pulse voltammetric technique was applied to investigate the electrochemical behavior of alfuzosin hydrochloride at two different working electrodes: silica gel modified carbon paste and pencil graphite electrodes (PGE). The voltammetric conditions were optimized using cyclic voltammetry, showing an irreversible anodic peak in Britton-Robinson buffered medium (pH 6) at 0.86-0.90 V. The electrochemical responses were linearly correlated with alfuzosin concentrations (R2> 0.999) in the ranges of 0.6-20 and 0.3-20 µM, exhibiting higher electrocatalytic activity at PGE with a low detection limit/ detectability of 0.099 µM. In addition, this study was a successful attempt for the drug determination in tablets and spiked urine samples with green profile evaluation, employing the National Environmental Methods Index, analytical Eco-Scale score, and Green Analytical Procedure Index.