Development and validation of a simple and efficient HPLC method for the determination of zonisamide in pharmaceuticals and human plasma

A simple and efficient liquid chromatographic method has been developed and validated for the determination of zonisamide in pharmaceuticals and human plasma. Plasma samples are analyzed after one step protein precipitation with methanol, and chromatographic separation of zonisamide and chloramphenicol (internal standard) is carried out using a C₁₈ column and the optimum mobile phase of acetonitrile/methanol/distilled water (20: 10: 70, v/v/v). The method is validated in both mobile phase and human plasma, and the obtained limits of quantification values are 0.099 and 0.12 μg/mL in mobile phase and human plasma, respectively. Fully validated method is reproducible and selective for the determination of zonisamide in pharmaceuticals and human plasma.