Colorimetric estimation of alfuzosin hydrochloride in pharmaceutical preparation based on computational studies

Abstract

Computational and theoretical studies were done electronically and geometrically to find a suitable, selective and sensitive coupling agent applicable for diazocoupling estimation of alfuzosin hydrochloride (ALF). These studies revealed that 8-hydroxyquinoline (8-HQ) fits better with ALF than other coupling agents based on its higher calculated interaction energy. The proposed method is based on the formation of a red colored chromogen through the reaction of ALF with sodium nitrite in acid medium to form a diazonium ion, which was coupled with 8-HQ. Different variables affecting the reactions are optimized. Beer's law is obeyed over the concentration range of 1–12 μg ml⁻¹. The Job's plot analysis was applied and the stoichiometric ratio of ALF : 8-HQ was found to be 1 : 1. The method was successfully applied to the determination of ALF in pharmaceutical formulations with good accuracy and precision.