Long-term stability of trimix: a three-drug injection used to treat erectile dysfunction.
A three-drug injection mixture of alprostadil 12.5 microgram/mL, papaverine hydrochloride 4.5 mg/mL and phentolamine mesylate 0.125 mg/mL in bacteriostatic 0.9% sodium chloride injection was evaluated for stability at 23 deg C, 4 deg C, -20 deg C and -70 deg C. The injection remained clear and colorless in all samples throughout the study. Chemical stability testing was performed using stability-indicating high-performance liquid chromatographic analysis. Alprostadil was the least stable of the drug components at room temperature and under refrigeration. About 8% alprostadil loss occurred in five days at room temperature; under refrigeration losses of about 6% and 11% occurred after 1 and 2 months, respectively. Frozen at -20 deg C and -70 deg C, less than 5% loss of any of the drug componenets occurred in 6 months. A beyond-use date of 6 months when stored frozen at -20 deg C and 1 month when stored refrigerated at 4 deg C is appropriate for batches of the injection that have passed sterility testing. Room temperature exposure should be limited, and the vial should be returned to refrigeration as soon as possible.
Division of Pharmacy, The University of Texas, M.D. Anderson Cancer Center, Houson, Texas.
Lawrence A
LA
Trissel
Yanping
Y
Zhang