Novel approaches of erythrosine B as a food dye-derived spectroscopic probe for assessing trospium chloride in raw material and dosage form

Abstract

Two facile spectroscopic methodologies were designed for estimating trospium chloride (TPM) in raw material and tablets with high operational reliability and selectivity. The methods were based on using erythrosine B (EB) as a spectroscopic tool for ion-pair complex formation with the drug. In a mild acidic medium of Britton Robinson buffer (pH 4.0), the ionized hydroxyl group in the reagent interacted with the ionized amine in the studied drug. Method I was based on the spectrophotometric measuring of the absorbance of the reaction product at 557 nm. Method II was based on spectrofluorimetric measurement of the quenching effect of TPM on the inherent fluorescence of EB at 550 nm (λ_ex. = 528 nm). The two methods showed linearity through ranges 1.0-10.0 and 0.5-10.0 μg/ml for Methods I and II, respectively. The suggested methods were exploited for analyzing TPM in Trospamexin® tablets and showed good applicability. The designed systems were validated as per International Conference on Harmonization guidelines. Experimental conditions were modulated to obtain the best sensitivities. The quenching mechanism was investigated and the quenching constant was computed relying on the Stern-Volmer equation. Environmental impact was appraised using novel metric green tools, GABI, and AGREE. The suggested systems excelled over other reported methods in terms of greenness, sensitivity, and cost-effectiveness.

Keywords: erythrosine B; green; trospium chloride.