Determination of Tolterodine Tartrate in Bulk and Formulation by Extractive Colorimetric Method using Tropaeolin OOO-1

Purpose: To develop a new simple, accurate, precise and fully validated extractive colorimetric method for the determination of tolterodine tartrate (TL) in bulk and in tablet dosage form.
Method: A chloroform extractable orange red complex formed between the acid dye, tropaeolin OOO-1 and tolterodine in acid media is the basis for this method. The maximum wavelength of absorbance of the complex was 503 nm. The validation parameters such as stability, accuracy, precision, robustness and ruggedness were evaluated according to International conference on harmonization (ICH) and United States Pharmacopoeia (USP) guidelines.
Results: The absorbance of the complex obeyed Beer law over the range 1 - 30 μg/mL with a correlation coefficient of 0.9945, with a molar absorptivity and Sandal’s sensitivity of 0.0398 and 1.1954 x 10⁴, respectively. The lower limit of detection (LOD) and of quantification (LOQ) of the method were 0.08 and 1 μg mL^-1, respectively.
Conclusion: The developed method is validated and has high recovery and precision, and thus is suitable for routine analysis of the drug in bulk and formulations.

Keywords
Tolterodine; Tropaeolin; Extractive colorimetry; Validation; Solid dosage