Study on Preparation of a Chitosan/Vitamin C Complex and Its Properties in Cosmetics

Abstract

In order to expand the application of chitosan in cosmetics, it was modified with vitamin C to prepare a chitosan/vitamin C complex (CSVC complex), which was characterized using ultraviolet-visual, Fourier transform infrared, and differential scanning calorimetry techniques. Its hygroscopicity, moisture retention, antioxidant and antibacterial activities, and environmental stability were also determined. The results showed that a mass ratio of chitosan to vitamin C of 1:1 that reacted at 25℃ for 90 minutes in a medium of isopropanol–water, away from light, with the unreacted vitamin C being removed by dialysis gave a white powder (CSVC complex) after freeze-drying. The CSVC complex had good water solubility, a viscosity average molecular weight of 233.7 kDa, and a vitamin C content of 22.64%. Structure characterization confirmed that the CSVC complex was composed of the amine (C-2 position) of chitosan and the hydroxyl group (C-3 position) of vitamin C by electrostatic attraction. The complex had a significantly better scavenging effect on hydroxyl free radicals than chitosan, and the minimum inhibitory concentration against Escherichia coli was 5 mg/mL. Its moisturizing and hygroscopic properties were better than chitosan, and its stability was better than that of vitamin C. These results provide the basis for the CSVC complex as a multifunctional raw material for cosmetic use because of its antioxidant, moisturizing, antibacterial, and film-forming properties.