Electrochemical studies of ropinirole, an anti-Parkinson's disease drug

The oxidation behaviour of a potent anti-Parkinson's disease drug ropinirole hydrochloride was investigated over a wide pH range in aqueous solution at glassy carbon electrode using cyclic and square-wave voltammetry. The oxidation of drug is a pH dependent irreversible process and occurs in two steps. The mechanism of the oxidation process has been discussed. Using the sharp oxidation response in 0.1 M sulphuric acid at a potential of +1.27 V attributed to the oxidation of indol-2-one ring in drug molecule, rapid electroanalytical methods for the determination of ropinirole by pulse voltammetric techniques were developed and validated. The proposed voltammetric methods were applied to direct quantification of ropinirole in film-coated tablets, with results in close agreement (at 95% confidence level) with those obtained using a comparative HPLC method.