Stability-indicating assay for orphenadrine hydrochloride by reversed-phase high-performance liquid chromatography

Abstract A rapid method based on reversed-phase high-performance liquid chromatography (HPLC) is described for the separation and quantitation of orphenadrine hydrochloride and its major degradation product o -methylbenzhydrol. The method has been applied to the assay of orphenadrine hydrochloride and o -methylbenzhydrol in the commercially available tablet and injectable formulations and in a hospital-formulated syrup. The method is stability-indicating and has been used for preliminary studies of the degradation of orphenadrine [1% (m/v)] in aqueous solutions stored at various pH values at elevated temperature. The assay results obtained for the dosage forms and the preliminary stability study confirm the HPLC method as being suitable both for routine quality control and for stability studies on orphenadrine hydrochloride preparations.