Stability of Regular Human Insulin Extemporaneously Prepared in 0.9% Sodium Chloride in a Polyvinyl Chloride Bag

Abstract

Purpose The purpose of this study was to evaluate the extended stability of extemporaneously prepared regular human insulin 100 units in 0.9% sodium chloride at a total volume of 100 mL under refrigeration. Methods Three admixtures of regular human insulin were prepared aseptically under a laminar flow hood at time zero. They were prepared by withdrawing 1 mL of regular human insulin with a concentration of 100 units/mL and adding it to a sufficient quantity of 0.9% sodium chloride for injection in a Polyvinylchloride (PVC) bag to yield a total volume of 100 mL. The 3 admixtures were stored refrigerated(2°C to 8°C [36°F to 46°F]) and three 1 mL samples of each admixture were withdrawn, transferred to a test tube, and frozen(–30°C to −15°C [–22°F to 5°F]) at hours 0, 6, 12, 36, 48, 72, 96, 120, 144, and 168. Insulin concentrations were measured by chemiluminescent immunoassay. The time points were considered stable if the mean concentration of the samples exceeded 90% of the equilibrium concentration at hour 6. Results The equilibrium concentration was 0.57 units/mL. Time points were considered stable if the mean concentration was at least 0.52 units/mL. All time points retained at least 90% of the equilibrium concentration with the exception of hour 120(0.46 ± 0.05 units/mL). At hour 168, the mean concentration was 0.63 ± 0.07 units/mL. Conclusion Regular human insulin 100 units added to 0.9% sodium chloride for injection in a PVC bag to yield a total volume of 100 mL is stable for 168 hours when stored at 2°C to 8°C(36°F to 46°F).