Stability of nicardipine hydrochloride in intravenous solutions

The stability of nicardipine hydrochloride in large-volume i.v. solutions was studied. Admixtures of nicardipine hydrochloride 0.05 and 0.5 mg/mL were prepared in 5% dextrose and 0.45% sodium chloride injection, 5% dextrose and 0.9% sodium chloride injection, 0.45% sodium chloride injection, 0.9% sodium chloride injection, 5% dextrose and lactated Ringer's injection, 5% dextrose injection, lactated Ringer's injection, 5% sodium bicarbonate injection, and 5% dextrose injection with potassium chloride 40 meq/L. Two glass and two polyvinyl chloride (PVC) containers of each solution were prepared and stored at ambient room temperature under normal fluorescent light. Samples were removed and tested for nicardipine concentration by stability-indicating high-performance liquid chromatography at 0, 24, 48, and 72 hours and seven days. Testing included visual checking and optical density measurements. The admixtures remained clear and slightly yellow except for nicardipine hydrochloride in sodium bicarbonate injection, which showed immediate precipitation, and nicardipine hydrochloride in lactated Ringer's injection, which increased in optical density at 400 nm over time. There were no significant changes in nicardipine concentrations in nicardipine concentrations in glass containers. Admixtures stored in PVC containers showed a slow, constant decline in nicardipine concentrations, sometimes to less than 85% of the initial drug concentration within 24 hours, except for nicardipine hydrochloride in lactated Ringer's injection or 5% dextrose and lactated Ringer's injection, which showed an immediate and continuing rapid loss. Nicardipine hydrochloride 0.5 and 0.05 mg/mL in eight i.v. solutions was stable in glass containers for up to seven days. Drug concentrations slowly decreased in PVC containers. The drug was not stable in 5% sodium bicarbonate injection or in PVC bags containing lactated Ringer's injection or 5% dextrose and lactated Ringer's injection.