Study on Preparation of a Chitosan/Vitamin C Complex and Its Properties in Cosmetics
Liu Liping, Kexin Li, Huipu Ding, Jia Lv, Jie Zhang
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.