Stability of intravenous nitroglycerin solutions.

Area of Science:

• Pharmaceutical Science
• Clinical Pharmacy
• Drug Stability

Background:

• Intravenous nitroglycerin is a critical vasodilator used in various clinical settings.
• Understanding the stability of intravenous nitroglycerin is crucial for ensuring therapeutic efficacy and patient safety.
• Formulation and storage conditions can impact the stability of parenteral drugs.

Purpose of the Study:

• To evaluate the stability of intravenous nitroglycerin solutions prepared from different sources (sublingual tablets, powder).
• To assess the impact of storage conditions (temperature, light, container materials) on nitroglycerin concentration.
• To identify factors contributing to nitroglycerin degradation in parenteral solutions.

Main Methods:

• Nitroglycerin concentration was quantified using high-pressure liquid chromatography (HPLC).
• Solutions were prepared from sublingual tablets or a nitroglycerin-lactose adsorbate.
• Stability was tested under various storage conditions including refrigeration, room temperature, and contact with different materials (glass, plastic, rubber).

Main Results:

• Refrigerated stock solutions (0.8-1.0 mg/ml) remained stable for 6 months.
• Room temperature storage led to a 20% loss in concentration within 3 months.
• Solutions stored in glass bottles for 24 hours showed a maximum 18% loss.
• Significant nitroglycerin loss occurred upon contact with rubber stoppers, plastic IV bags, and administration sets (especially those with burets) due to sorption.
• Light and vehicle (saline, dextrose) did not significantly affect stability in glass containers.

Conclusions:

• Intravenous nitroglycerin solutions are stable when refrigerated and stored in glass containers.
• Degradation is accelerated at room temperature and significantly impacted by sorption to rubber and plastic materials.
• Minimizing contact with rubber and plastic surfaces is essential for maintaining nitroglycerin concentration in intravenous preparations.