Separation and quantitation of possible degradation products of procarbazine hydrochloride in its dosage form

A stability-indicating assay for the degradation products of procarbazine hydrochloride was developed using high-pressure liquid chromatography. The method uses a buffered methanol-water mobile phase on a reversed-phase column. Concentrations of degradation products as low as 0.04 mg/ml, 0.02% degradation, can be quantitated using an internal standard of cinnamyl alcohol. The typical range for degradation products in procarbazine capsules is 0.1-0.5% after as long as 4.5 years.