Development of Two Charge-Transfer Complex Spectrophotometric Methods for Determination of Tofisopam in Tablet Dosage Form

Purpose: To develop an easy, fast and sensible spectrophotometric method for determination of tofisopam in tablet dosage form.
Methods: Tofisopam as n-electron donor is react with two π-acceptors namely: chloranilic acid (ChA), and 7,7,8,8 tetracyanoquinodimethane (TCNQ) to form charge-transfer complexes. The obtained complexes were tested spectrophotometrically at 520 and 824 nm for ChA and TCNQ, respectively. The optimal conditions affecting the reaction status were surveyed and optimized, and the results compared with Japanese Pharmacopeia method.
Results: The calibration curve were obeyed Beer`s low in the ranges 25 – 125 and 30 – 150 μg/mL for ChA and TCNQ, respectively. The lower limit of detection was 8.0 and 10.0 μg/m for ChA and TCNQ, respectively. The slope and intercept of the calibration graphs were 0.0025 and 0.011, and 0.0115 and -0.237 for ChA and TCNQ, respectively
Conclusion: The proposed methods have successfully been applied to determination of tofisopam with good accuracy and precision. The methods are accurate as the Japanese pharmacopeial method amd may be applied for routine analysis in quality control laboratories.

Keywords
Charge-transfer complex; Tofisopam; Chloranilic acid; Tetracyanoquinodimethane; Spectrophotometry