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

Amer Alanazi,Mohammed Abounassif,Haitham Alrabiah,Gamal Abdel-Haiz Mostafa

doi:10.4314/tjpr.v15i1.21

Abstract

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

Highlights

Tofisopam is a 1, 2-benzodiazepine and is analogous with other anxiolytic benzodiazepines which are generally 1,4- or 1,5-substituted
Tofisopam is a nitrogenous compound that act as n-donor which react with π-acceptors e.g. chloranilic acid (ChA) and 7, 7, 8, 8 tetracyanoquinodimethane (TCNQ) to form charge transfer complex
The resulting complexes exhibit an absorption maximum at 520 nm with ChA, instantaneously while the other complex exhibit a maximum absorbance at 841 nm (TCNQ) after heating at 70 oC for about 20 min

Summary

Introduction

Tofisopam is a 1, 2-benzodiazepine and is analogous with other anxiolytic benzodiazepines which are generally 1,4- or 1,5-substituted. Tofisopam does not have anticonvulsant, calming [1], skeletal reduce tension, motor skill-damaging or amnestic [2] features (Figure 1) [3]. Tofisopam is used for the therapy of worry and alcohol retraction, and is prescribed in a dose of 50 - 300 mg daily, separated into three doses. Tofisopam is not reported to cause dependence to the same extent as other benzodiazepines, but is advised to be prescribed for a maximum of 12 weeks. Tofisopam is a PDE10A inhibitor, is said to be a beneficial therapy for mental disorder (4). The pharmacological effectiveness of tofisopam (TOF) and its inherent toxicity have encouraged efforts aimed at the development of different assay methods for the drug

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Conclusion