title: Evaluation of the maximum beyond-use-date stability of regular human insulin extemporaneously prepared in 0.9% sodium chloride in a polyvinyl chloride bag.
abstract: BACKGROUND
  Regular human insulin 100 units added to a sufficient quantity of 0.9% sodium chloride, to yield a total volume of 100 mL within a polyvinylchloride bag, is accepted to be stable for 24 hours due to physical denaturation and chemical modification. The objective of this study was to evaluate the extended stability of such extemporaneously prepared regular human insulin, stored under refrigeration, to the maximum beyond-use-date allowed by United States Pharmacopeia chapter 797.
  
  
  METHODS
  At time "0" three admixtures of regular human insulin 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 bag to yield a total volume of 100 mL. The three admixtures were stored under refrigeration (2°C-8°C [36°F-46°F]), and one sample of each admixture was withdrawn and tested in duplicate at 0, 6, 24, 48, 72, 144, 168, 192, 216, 240, 312, and 336 hours. Utilizing high performance liquid chromatography, each sample underwent immediate testing. The time points were stable if the mean concentration of the samples exceeded 90% of the equilibrium concentration at 6 hours.
  
  
  RESULTS
  The equilibrium concentration was 0.89 units/mL. Time points were stable if the mean concentration was at least 0.80 units/mL. All time points retained at least 90% of the equilibrium concentration, with the exception of hour 168 (0.79 ± 0.03 units/mL). At 192 hours the mean concentration was 0.88 ± 0.03 units/mL. At 336 hours the mean concentration was 0.91 ± 0.02 units/mL.
  
  
  CONCLUSIONS
  Based on these results, regular human insulin 100 units added to 0.9% sodium chloride for injection in a polyvinylchloride bag to yield a total volume of 100 mL is stable for up to 336 hours when stored at 2°C-8°C (36°F-46°F).
authors.affiliation: Department of Pharmacy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Megan A
authors.initials: MA
authors.lastname: Rocchio
authors.forename: Caryn D
authors.initials: CD
authors.lastname: Belisle
authors.forename: Bonnie C
authors.initials: BC
authors.lastname: Greenwood
authors.forename: Michael C
authors.initials: MC
authors.lastname: Cotugno
authors.forename: Paul M
authors.initials: PM
authors.lastname: Szumita
keywords: USP 797; insulin; polyvinylchloride; sodium chloride; stability; storage; temperature