Chem. Pharm. Bull. 55(10) 1483—1488 (2007)

sodium salt of 1-[5-(4-nitrophenyl)furfulidene amino]imidazolidene-2,4-dione. It is a muscle relaxant reported to act by blocking muscle concentration beyond the neuromuscular junction. It is described for the symptomatic relief of muscular spasm due to condition such as stroke, multiple sclerosis, spinal cord injury and cerebral palsy. Dantrolene sodium is used also intravenously in the treatment of malignant hyperthermia. Only few liquid chromatographic methods were described for assay of dantrolene sodium in dosage form and biological fluids. The chromatographic methods usually necessitate sample pretreatment and time-consuming extraction steps prior to analysis of the drug. Moreover, these methods required expensive equipment and considerable skills are necessary to operate them successfully. Although no official analytical method for determination of dantrolene sodium is reported in British or the United States pharmacopoeia an official electrometric titration method for determination of the drug is available in the Japanese pharmacopoeia. Besides, no any information is available in the literature to date concerning the electroreduction of dantrolene sodium or its electroanalytical determination. Therefore, the present work aimed to study the electroreduction pathway of dantrolene sodium at the mercury electrode and to describe simple and precise electroanalytical procedures for its determination in bulk form and pharmaceutical formulation.