RAPID SPECTROPHOTOMETRIC DETERMINATION OF TRIFLUOPERAZINE DIHYDROCHLORIDE AS BASE FORM IN PHARMACEUTICAL FORMULATION...

Two simple and selective spectrophotometric methods are described for the determination of trifluoperazine dihydrochloride (TFH) as base form (TFP) in bulk drug, and in tablets. The methods are based on the molecular charge-transfer complexation of trifluoperazine base (TFP) with either 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (DNP). The yellow colored radical anions formed are quantified at 410 run (PA method) or 415 nm (DNP method). The assay conditions were optimized for both the methods. Beer's law is obeyed over the concentration ranges of 1.5-24.0 pg/mL in PA method and 5.0-80.0 µg/mL in DNP method, with respective molar absorptivity values of 1.03 x 10(4) and 6.91 x 10(3) L mol-1 cm-1. The reaction stoichiometry in both methods was evaluated by Job's method of continuous variations and was found to be 1 : 2 (TFP : PA, TFP : DNP). The developed methods were successfully applied to the determination of TFP in pure form and commercial tablets with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level and the results showed no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the accuracy and reliability of the methods were confirmed by recovery studies via standard addition technique.