The availability of nitroglycerin from parenteral solutions.

The availability of nitroglycerin from solution infused from Viaflex plastic infusion bags or glass infusion bottles through Buretrol plastic giving sets has been examined. Each of the individual components of the infusion bag/giving set system (i.e. infusion bag, burette and infusion tubing) sorbed nitroglycerin to a significant extent. It was found that the event and rate of nitroglycerin disappearance from solutions stored in each of the components were in the rank order: tubing greater than burette greater than infusion bag. The disappearance kinetics of nitroglycerin from solutions stored in each component was more accurately described by a 'diffusion' model than by the 'two compartment kinetic' model reported previously. The dimensions of the components and the volume of solution used were determinants of the rate and extent of nitroglycerin disappearance. In simulated infusions of nitroglycerin through plastic infusion bag (or glass bottle)/giving set system the flow rate of solution through the plastic infusion tubing affected the concentration of nitroglycerin in the effluent and the extent of sorption by the components of the infusion delivery system. The loss of nitroglycerin in these studies could be accounted for solely by the sorption of nitroglycerin by the plastic components of the infusion bag/giving set system.