The availability of nitroglycerin from parenteral solutions

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Materials Science

Background:

• Nitroglycerin (NG) is a critical vasodilator used in various clinical settings.
• The stability and availability of NG during intravenous infusion can be compromised by the administration materials.
• Understanding drug-sorption interactions is crucial for ensuring therapeutic efficacy.

Purpose of the Study:

• To quantify the sorption of nitroglycerin (NG) by common intravenous infusion components.
• To investigate the kinetics and influencing factors of NG disappearance from infusion systems.
• To assess the impact of administration parameters on NG concentration during simulated infusions.

Main Methods:

• Solutions of NG were stored in Viaflex plastic infusion bags, glass bottles, and Buretrol plastic giving sets.
• Sorption of NG by individual components (bag, burette, tubing) was measured.
• Disappearance kinetics were modeled using diffusion and two-compartment models.
• Simulated infusions were conducted to evaluate the effect of flow rate on NG concentration.

Main Results:

• All plastic components (infusion bag, burette, tubing) significantly sorbed NG.
• The rate of NG disappearance followed the order: tubing > burette > infusion bag.
• A diffusion model provided a better fit for NG disappearance kinetics than a two-compartment model.
• Infusion flow rate directly impacted NG concentration in the effluent and overall sorption.

Conclusions:

• Plastic infusion components, particularly tubing, significantly absorb nitroglycerin, reducing its availability.
• Drug loss is primarily due to sorption, influenced by component dimensions and solution volume.
• Administration parameters like flow rate must be considered to manage NG concentration during infusion therapy.