ASSAY AND STABILITY-INDICATING CAPILLARY ZONE ELECTROPHORETIC METHOD FOR THE DETERMINATION OF MODAFINIL IN BULK AND ITS PHARMACEUTICAL PREPARATIONS

Abstract

A simple, sensitive, and cost effective capillary zone electrophoresis (CZE) method for the determination of the novel wake promoting agent, modafinil in pharmaceutical formulations has been developed and validated. The CZE separation was performed using 50 μm i.d × 56 cm fused silica capillary under the following conditions: capillary temperature, 25°C; applied voltage, 25 kV; 20 mM H₃PO₄ − 1 M tris running buffer (pH 9.0); detection wavelength, 225 nm. Phenobarbital was used as the internal standard. The method was validated and showed not only good precision and accuracy but also good robustness. The calibration was linear from 5 to 250 µg mL⁻¹. The accuracy values ranged from 101.6 to 105.3%. The good accuracy values obtained indicate the potential of this method for the determination of the analyte in pharmaceutical formulations. The LOD and LOQ were 1.2 and 3.5 μg mL⁻¹, respectively. The method has been successfully applied to the determination modafinil in pharmaceutical tablet formulations. Excipients present in the tablets and degraded products from different stress conditions did not interfere in the assay.

Keywords:

• capillary zone electrophoresis
• degradation products
• forced stress tests
• modafinil
• pharmaceutical analysis

ACKNOWLEDGMENTS

Financial support of the work by a Universiti Sains Malaysia (USM) Postgraduate Research Grant Scheme (USM-RU-PRGS), 1001/PKIMIA/841008 and a USM Research University grant scheme are gratefully acknowledged.

Notes

IS, internal standard.

n = no. of introduction, (three preparations for each concentration).

*Please refer to text for details.

*All samples were stressed at 75°C for 15 h.