Stability of dobutamine hydrochloride and verapamil hydrochloride in 0.9% sodium chloride and 5% dextrose injections.

The stability of dobutamine hydrochloride (250 micrograms/ml) and verapamil hydrochloride (160 micrograms/ml) alone and in combination in 0.9% sodium chloride injection or 5% dextrose injection was studied. Solutions were stored both in plastic i.v. bags and in amber-colored glass bottles at 24 degrees C and 5 degrees C for up to seven days. Before storage and at various times during storage, solutions were assayed at least in triplicate by high-performance liquid chromatography, pH was recorded, and visual appearance was noted. All solutions tested under all conditions retained at least 90% potency for seven days. In plastic i.v. bags, dobutamine either alone or in combination with verapamil in both diluents turned a light-pink color in 24 hours at 24 degrees C. The intensity of the pink color increased with time in 0.9% sodium chloride injection; in 5% dextrose injection, solutions, became clear in 48 hours. The pH of solutions prepared in plastic i.v. bags in 5% dextrose injection decreased from 4.0 to 3.1 during the seven-day period at 24 degrees C; results for solutions in amber bottles were similar. At 5 degrees C, the pH and clarity of all solutions in bags and bottles remained stable for seven days. At the concentrations tested, dobutamine hydrochloride combined with verapamil hydrochloride is stable in 0.9% sodium chloride injection and 5% dextrose injection for 48 hours at 24 degrees C and for seven days at 5 degrees C.