A simple and sensitive method for the spectrophotometric determination of risperidone (RIS) is proposed. The method is based on the oxidation of the drug using chloramine-T (CAT) and the excess oxidant is determined by either xylene cyanol FF (XCFF) or malachite green (MG), the absorbances of which are measured at 612 or 619 nm for RIS-XCFF and RIS-MG respectively. Under the proposed optimum conditions Beer’s law is obeyed in the concentration range of 2.00- 26.00 and 2.00-18.00 μgmL-1 and the molar absorptivities are calculated to be 4.37×104 and 3.93×104 Lmol-1cm-1 for RIS-XCFF and RIS-MG systems. The limit of detection and quantification for RIS-XCFF and RIS- MG are found to be 0.891, 2.702 μgmL-1 and 0.529, 1.605 μgmL-1 respectively. The proposed method is applied successfully for the pharmaceutical formulations.
