Assessment of the Influence of Some Formulation Excipients on Vitamin C Stability

Formulating Ascorbic acid (Vitamin C, Vit C) presents many challenges due to its sensibility to oxidation. This study aimed to enhance the stability of Vit C in aqueous solutions through the addition of different excipients, including polyols (eg. Sorbitol, Glycerin and Propylene Glycol PG), sugars (eg. Xylose), viscosity modifiers (eg. Gum Arabic and Carbopol), acidity regulators (Citric and Tartaric Acids). The kinetics of Vit C degradation were evaluated by determining the reaction order, calculating rate constants and estimating shelf lives (t90). The results demonstrated that the shelf life of Vit C was enhanced when Sorbitol, Glycerin, Propylene glycol, Xylose, Gum Arabic and Tartaric Acid were used (the shelf lives ranged from 12 to 37 days compared to 8 days (in Control). However, lower shelf lives were reported when Carbopol and Citric Acid were used (t90 ≈ 5 days)