Stability of intravenous vitamin C solutions: a technical report

There has recently been a surge of interest in intravenous (IV) vitamin C as a potential therapy in intensive care unit (ICU) patients, particularly in those with septic shock. Establishing the safety and efficacy of IV vitamin C therapy through rigorously conducted randomised controlled trials is a priority. A key logistical issue for such trials is to establish the stability of IV vitamin C solutions prepared for infusion ahead of time. Accordingly, we aimed to assess the stability of IV vitamin C solutions over time using doses of vitamin C from previous pilot trials.

We used spectrophotometry to measure the concentration of vitamin C remaining in solutions of 1.5 g per 50 mL of 0.9% saline and 2.5 g per 50 mL of dextrose 5% in water (D5W) at 0, 1, 3, 6, 9, 24, 48, 72 and 96 hours after preparation. The concentration of vitamin C in these solutions over time was assessed at 4°C in the dark and at ambient temperature and light.

The concentration of vitamin C in diluted solutions was essentially unchanged over a period of 24 hours, and decreased less than 10% by 96 hours both at 4°C in the dark and at ambient temperature and light.

Our findings suggest that vitamin C solutions of 1.5 g per 50 mL of 0.9% saline and 2.5 g per 50 mL of D5W remain stable for up to 96 hours and do not need to be protected from light.