Spectrophotometric Determination of Tolterodine Tartrate via Charge-Transfer Complexation Reactions

A spectrophotometric method was developed for the determination tolterodine tartrate. The method is based on the formation of intensely colored charge-transfer complexes formed by the interaction of this drug as n-electron donors with Para-chloranilic acid (p-CA) and 2,3-dichloro-5,6-dicyano- 1,4-benzoquinone (DDQ) as the pi-acceptors. The colored complexes exhibit maximum absorption at 500 and 460 nm respectively. Beer's law is obeyed in the concentration ranges 20-380 and 18-230 mu g/ml using (p-CA) and (DDQ) respectively and the limits of detection and quantification are reported. The proposed method was applied to the determination of the drug in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise and reproducible as the official methods. The validity of method was established by recovery studies with satisfactory results.