Spectrophotometric determination of Risperidone in pharmaceutical preparations by Charge-Transfer Reactions

A simple, rapid and sensitive method for the spectrophotometric determination of risperidone (RIS) has been developed. The proposed method is based on the charge–transfer reactions of risperidone as electron donor, with 7,7,8,8,-tetra-cyanoquinodimethane (TCNQ) , 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) , tetracyanoethylene (TCNE) and chloranilic acid(CA) as ?-acceptors to give colored complexes. The experimental conditions such as reagent concentration, reaction solvent, temperature and time have been optimized to achieve the highest sensitivity. Beer's law is obeyed over the concentration ranges of 8 – 150, 25 – 250, 5 – 70 and 10 – 110 µgml-1 risperidone using DDQ, CA, TCNE and TCNQ respectively, with corresponding correlation coefficients of 0.9995, 0.9993, 0.9990 & 0.9997 and detection limits of 3.62, 8.66, 1.93 and 2 .85 µgml-1 for the reagents in the same order.