Affiliation: Faculty of Pharmaceutical Sciences, University of Sao Paulo, Av. Prof. Lineu Prestes 580, 05508-000 Sao Paulo, SP, Brazil.
A rapid and simple analytical capillary zone electrophoresis (CZE) method has been developed and validated for quantitative determination of atypical antipsychotic drug risperidone in commercially available film-coated tablets. CZE was performed in an uncoated fused-silica capillary 40.2 cm total length x 75 µm i.d. (30 cm effective length) using a 20 mmol mL-1 sodium phosphate solution containing 0.1% triethylamine (v/v), pH 2.5 adjusted with ortho-phosphoric acid as background electrolyte. The applied voltage was +28 kV and UV detection at 236 nm, nitrazepam was used as internal standard (IS). Under these conditions, the separation of risperidone was achieved in less than 2.5 min. The method was validated and response was found to be linear with determination coefficient better than 0.999. The repeatability and intermediate precision expressed as relative standard deviation were less than 1.5 %. The accuracy, resulting from recovery experiments, was between 98.84 and 101.24 %. The active pharmaceutical ingredient was subjected to acid, alkaline and neutral hydrolysis and oxidative stress conditions. No interference from degradation products and also from tablet excipients was observed. The method was simple, precise and fast and could be successfully applied for determination of risperidone in pharmaceutical dosage forms and can be used for routine analysis in pharmaceutical industries. Furthermore, the method can be used as a stability-indicating method.