Stability and antibacterial activity of complex gel with edible chitosan and carbomer

Chitosan, a cation polysaccharide, is a product of chitin by partial deacetylation. It can be dissolved in some acid solvents to be polyelectrolyte hydrogel. However, the hydrogel has low mechanical strength and stability, and is difficult to smear. Carbomer is a kind of cross-linked polyacrylic acid resin containing a large number of free carboxyl. The gel made of carbomer can form transparent film on the skin and has strong adhesiveness. Therefore, it has been widely used in novel pharmaceutic adjuvant, gel and cream production.In this study, a chitosan-carbomer complex gel was prepared using edible chitosan as a raw material, carbomer as a thickener, trolamine as a neutralizing agent, and the content of chitosan was 1%. The pH of the complex gel was also optimized for the best stability, chromaticity, water activity, texture and antibacterial activity. And its antibacterial effect was also studied.The results showed that the prepared chitosan-carbomer complex gel was yellowish, semi-solid and apt to smear. The appearance, elasticity, hardness, adhesiveness, gumminess of the gel was independent of pH. However, it was more stable in storage under the higher pH value. The chromaticity decreased with the rise of pH, illustrating that the complex gel and chitosan gel exhibited similar color in the pH range of 7.0-7.5. The complex gel was stable in texture and its properties had no significant change as the storage time extended. The antibacterial effect of the gel on Staphylococcus aureus, Escherichia coli, Candida albicans was outstanding in the pH range of 7.0-7.5, with the antibacterial activity of 92%, 94% and 96%, respectively. When applied to the thigh and inner side of the arm, the complex gel exhibited high compatibility with skin, and was easy-to-spread, and no peculiar odour and allergic phenomenon such as redness, itching, blisters, and small skin irritation were observed.The above results show that the prepared complex gel has a fine consistency with skin, and it can also inhibit the growth of E. coli, S. aureus, and C. albicans in the pH range of 7.0-7.5, suggesting that the product can be used in daily chemical products. In a word, this study improves the value of chitosan extracted from edible mushrooms, widens its applying range and provides the theory gist for its application.