Stability of dantrolene oral suspension prepared from capsules

The chemical stability of an extemporaneously compounded dantrolene oral suspension (5 mg/ml dantrolene sodium) in Syrup BP containing citric acid with and without methyl hydroxybenzoate preservative was studied on storage at 5, 25 and 40 degrees C for 150 days in high density polyethylene dispensing bottles. The amount of dantrolene free acid in suspension was monitored by a stability indicating HPLC assay. There was no significant decomposition of dantrolene under all storage conditions irrespective of the presence of preservative. The results show that the formulation of dantrolene oral suspension provides a convenient and stable dosage form for use in pediatric patients and in those unable to swallow capsules. It is recommended that the formulation be stored at room temperature and in the absence of microbiological testing a shelf-life of 30 days is proposed for the product prepared with preserved syrup.