Influence of physical characteristics of intravenous systems on drug delivery

The influence of multiple intravenous system factors on the time required to deliver a drug dose was evaluated in vitro using a factorial study design. The study factors included (1) 5 intraluminal tubing diameters, (2) 2 intravenous tubing positions, (3) 2 intravenous infusion rates, and (4) 2 intravenous tubing lengths. For each intravenous system that represented the respective combination of study factors, a 1-ml dose of 14C-labeled potassium penicillin G was administered and the effusate was collected over time. A liquid scintillation technique was used to quantitate the amount of drug delivered. In-line pressures that resulted from the experimental conditions were measured in order to examine for correlations between in-line pressure and alterations in drug delivery time. Analysis of variance and stepwise procedures were used to determine significance of these factors on drug delivery time. It was determined that complex fluid dynamics resulting from the combined influences of tubing diameter, tubing length and infusion rate appears to have a significant influence on drug delivery time. It is important to use efficient intravenous systems for intravenous therapy in order to predict and control intravenous drug delivery.