Nitroglycerin compatibility with intravenous fluid filters, containers, and administration sets

The effect of intravenous filters, containers and administration sets on nitroglycerin potency was studied. Solutions of nitroglycerin (50 and 100 microgram/ml) in water for injection, in 5% dextrose injection and in 0.9% sodium chloride injection were prepared. The concentration of these solutions was measured after (1) filtration through a 0.2-micron filter, (2) storage in glass and plastic containers and (3) administration through eight i.v. administration sets. Filters decreased nitroglycerin concentration by 2--55%. Nitroglycerin concentration was not changed after storage for 48 hours in glass bottles. In plastic i.v. bags, concentration decreases were substantial and related to surface contact area and storage temperature. The i.v. administration sets caused immediate, substantial decreases in nitroglycerin concentration that were a function of drip rate, surface area, length of exposure to tubing, and tubing materials. The study suggests that concentrations of nitroglycerin solutions could be reduced by as much as 80% when filtered, placed in a plastic i.v. bag and given through an i.v. administration set.