Incompatibility of diazepam injection in plastic intravenous bags

The compatibility of diazepam injection in plastic intravenous bags was studied. Dilutions of 10 mg/102 ml and 10 mg/202 ml diazepam in dextrose 5% in water, 0.9% sodium chloride, Ringer's injection and lactated Ringer's injection were stored in plastic i.v. bags at room temperature and examined for clarity throughout a 24-hour period and for pH initially and 24 hours after preparation. All solutions were filtered and then assayed 24 hours after preparation using UV spectrophotometry. Dilutions which did not demonstrate acceptable potency (≥90% of initial concentration) at 24 hours were prepared again and assayed spectrophotometrically after 30 minutes. Diazepam in 0.9% sodium chloride dilutions, stored in glass containers and plastic i.v. bags, were assayed throughout the 24-hour period. No visual incompatibilities were observed during the 24-hour period. The pH of the dilutions remained constant over the 24-hour period, ranging from about 5.0 in dextrose 5% in water to approximately 6.0 in lactated Ringer's injection. All prepared solutions demonstrated greater than 24% loss of potency 30 minutes after dilution when stored in plastic containers. The percentage of diazepam lost from solution appeared to increase as drug concentration and time increased. Solutions of diazepam in 0.9% sodium chloride stored in glass containers for 24 hours retained not less than 95% of initial potency. Diazepam appears to undergo a clinically important interaction with plastic i.v. bags which is a function of diazepam concentration and time. It is recommended that glass containers be used if it is necessary to administer diazepam in an infusion.