Intravenous nitroglycerin delivery: dynamics and cost considerations

After determining initial nitroglycerin (NTG) concentrations, NTG solutions were infused through polyvinylchloride (PVC) and polyethylene intravenous (IV) administration sets at rates of 6, 12, and 24 ml/hour. Delivered NTG concentrations were determined using a high-performance liquid chromatographic technique at predetermined and fixed time intervals during a 24-hour infusion. The relative availability of NTG with each infusion was determined by dividing the area under the time concentration curve for delivered NTG by the area under the curve, assuming that the initial NTG concentration was delivered constantly over the 24-hour infusion period. For the PVC administration set, the relative availabilities of NTG were 41.5%, 62.9%, and 76.0% for the 6, 12, and 24 ml/hour infusions, respectively. Additionally, the concentration of NTG delivered varied considerably with time and infusion rate. For the polyethylene administration set, the relative availabilities of NTG were 97.3%, 96.8%, and 96.3% for the 6, 12, and 24 ml/hour infusions, respectively. Considerably less NTG solution was required to deliver the same amount of drug when polyethylene administration sets were used to infuse NTG. Polyethylene IV administration sets can be used to accurately deliver the labeled NTG concentration without resulting in increased cost.