Bulk: Cyclodisone stored for 90 days at room temperature and at 50 °C under both dark and light conditions was stable (HPLC). Samples stored at 50 °C turned a light tan color. Solution: 180 mg of Cyclodisone was dissolved in 60 mL of DMSO/water (50/50, v/v). Aliquots of this solution (5 mL) were diluted to 10 mL with internal standard solution (5 mL, phenol 1.8 mg/mL in CH3CN/water, 20/80, v /v) and the concentration was determined over a 4 hour period using the HPLC system described below. The t90 was 320 min.