Stability of carmustine in the presence of sodium bicarbonate.

The stability of carmustine in 5% dextrose injection and 0.9% sodium chloride injection, with and without added sodium bicarbonate, was studied at room temperature. Solutions of carmustine (0.1 mg/ml) in dextrose or saline with and without added sodium bicarbonate (1 meq/ml) were prepared. After 0, 15, 30, 60, and 90 minutes, aliquots of each test solution were analyzed for carmustine using the Bratton-Marshall test with absorbance at 540 nm. There was no significant decomposition of carmustine in dextrose or saline alone. However, the addition of sodium bicarbonate increased carmustine degradation; after 90 minutes, approximately 73% of the active drug remained. It is recommended that carmustine be neither admixed with nor administered piggyback with parenteral infusion solutions containing sodium bicarbonate.