Thiamine destruction by sodium bisulfite in infusion solutions

The degree of degradation of thiamine hydrochloride in sodium bisulfite-containing infusion solutions was investigated. Two amino acid and one electrolyte infusion solution containing sodium bisulfite and four infusion solutions (5 and 10% dextrose, Lactated Ringer's, and 0.9% sodium chloride injections) without sodium bisulfite were obtained in 500-ml glass or plastic containers. Three thiamine sources, two commercial multivitamin preparations, and one investigational multivitamin product were added to the infusion solutions. The percentage of added thiamine remaining after storage was determined in four experiments: (1) The investigational product was added to the infusion solutions with bisulfite, and the determinations were made after 24 hours of storage at room temperature (RT) under both light and dark conditions; (2) the two commercial multivitamin preparations were mixed with an amino acid solution containing bisulfite and the determination was made after 24 hours of storage at RT under dark conditions; (3) the investigational product was added to the infusion solutions with bisulfite, and the determinations were made after 2, 4, 6, 8, and 24 hours storage at 7 degrees C and following four hours at RT under dark conditions; and (4) the investigational product was added to the four infusion solutions without bisulfite, and the determinations were made after 24 hours of storage at RT under both light and dark conditions. In the infusion solutions containing bisulfite, the stability of thiamine was inversely related to the pH. In an amino acid solution at a pH of 6.5, only 3-8% of the added thiamine was found after 24 hours storage at RT, and only 37% was found after 24 hours at 7 degrees C. In the electrolyte solution with bisulfite (pH = 5), the percentages of thiamine remaining after 24 hours RT and 7 degrees C storage were 50 and 69%, respectively. Light exposure was not found to affect the stability of thiamine in the solutions containing bisulfite. In the infusion solutions without bisulfite, a minimal loss of thiamine occurred even though the pH range was 4.7-5.6. The degradation effect of light exposure was greater for the solutions stored in plastic than in glass. Infusion solutions containing bisulfite were found to be unsuitable vehicles for the administration of vitamin formulations containing thiamine. If a patient must receive multivitamins in infusion solutions with bisulfite, the solutions should be used immediately after their preparation, and the patient should be monitored for signs of thiamine deficiency.