Sensitive Spectrophotometric Assay of Muscarinic Receptor Antagonist Tolterodine Tartrate in Bulk Drug and Pharmaceutical Formulations

Abstract

Objective: Simple, sensitive, and accurate spectrophotometric methods have been developed for the assay of tolterodine tartrate (TOL) in bulk drug and pharmaceutical formulations. Methods:The proposed methods are based on oxidation reaction of TOL with a known excess of cerium(IV) ammonium sulfate as an oxidizing agent in acid medium followed by determination of unreacted oxidant by adding a fixed amount of dye, e.g., amaranth (AM), rhodamine 6G (Rh6G), and indigo carmine (IC) followed by measuring the absorbance at 520, 530, and 610 nm, respectively. The effect of experimental conditions was studied and optimized.Results: The Beer's law was obeyed in the concentration ranges of 1.0-10, 1.0-12, and 0.5-9.0 μg/mL using AM, Rh6G, and IC dyes, respectively, with a correlation coefficient ≥0.9995. The calculated molar absorptivity values are 1.868×10 4 , 1.008×10 4 , and 1.623×104 L/mol/cm using AM, Rh6G, and IC dyes, respectively. The limits of detection and quantification were reported. Intraday and interday accuracy and precision of the methods have been evaluated. No interference was observed from the additives. Conclusion:The proposed methods were successfully applied to the assay of TOL in tablets preparations, and the results were statistically compared with those of the reported method by applying Student's t-test and F-test. The reliability of the methods was further ascertained by performing recovery studies using the standard addition method.

Extractive-Spectrophotometric Determination of Some Antimuscarinic Antagonist in Tablet Formulations Using Eriochrome Cyanine R

“…1c). The methods reported in the literature for its determination either in biological matrix or in pharmaceutical formulations are spectrophotometric [30][31][32][33], LC [34][35][36], HPLC [37][38][39][40][41], potentiometric [42] and electrochemical methods [43,44].…”