Spectrofluorimetric Method for the Determination of Tolterodine In Human Plasma and Pharmaceutical Preparations by Derivatization with Dansyl Chloride

Objective: Tolterodine (TOL) is an anti-muscarinic drug used for the symptomatic treatment of urinary incontinence. Analytical methods in the literature are not sensitive enough for the assay of drug substance biological fluids. To make up the deficit, we developed a sensitive, costreduced spectrofluorimetric method for the determination of TOL in plasma and pharmaceutical preparations. Methods: TOL has a phenolic hydroxyl group that reacts with dansyl chloride. The spectrofluorimetric method is based on this reaction in the presence of a bicarbonate solution of pH 9.5 to give a highly fluorescent derivative, which can be measured at 590 nm with an excitation wavelength at 360 nm in dichloromethane. Different experimental parameters affecting fluorescence intensity were optimized. The relationship between fluorescence intensity and TOL concentration was investigated. Results: The developed method is linear in the concentration range of 5-60 ng mL−1 with a minimum detectability of 0.136 ng mL−1. The recovery was 100.48%. Conclusion: A simple, cost-effective, and sensitive spectrofluorimetric method was developed and validated for the determination of TOL in human plasma and pharmaceutical preparations using dansyl chloride. According to this validation study, it is possible to use this proposed method for the routine analysis of the drug and for conducting bioavailability and bioequivalence studies with good accuracy and precision.