Application of a quinone-based fluorophore for spectrofluorimetric determination of albendazole in pure form and pharmaceutical formulations

Abstract

A spectrofluorimetric method was developed for the determination of albendazole (ALB) through charge transfer (CT) complex formation with 7,7,8,8-tetracyanoquinodimethane (TCNQ). TCNQ was found to react with ALB to produce a stable complex, and the fluorescence intensity of the complex was enhanced to 25 times higher than that of the studied drug itself. Different experimental parameters that affect the fluorescence intensity were carefully studied, at optimum reaction conditions, the drug–TCNQ complex showed an excitation maxima at 295 nm and an emission maxima at 476 nm. A rectilinear calibration graph was obtained in the concentration range of 100–800 ng ml⁻¹. Thermodynamics parameters were calculated as: association constant KC of 7.28 × 10³ mol⁻¹ dm³ and a Gibbs free energy ΔG° of −4.66 kJ mol⁻¹. The developed method was applied successfully to the determination of the studied drug in its pharmaceutical dosage form with good precision and accuracy compared to official and reported methods as revealed by t- and F-tests.