Applications of CD Inclusion Complexes

CD itself is non-toxic, non-allergic, and does not irritate the skin. When encapsulating the irritating ingredients into CD cavities to form CD complexes, the irritation of the encapsulated substances can be reduced. Therefore, the inclusion complex formed by CDs and irritating ingredients can be used to prepare low-irritation product formulas. For example, cream was prepared with stearic acid, liquid paraffin, and glycerin as the base and β-CD-ibuprofen inclusion complex as the main body, which effectively reduces the irritation of ibuprofen ^[1].

CD can encapsulate cosmetic ingredients with antimicrobial functions to form inclusion complexes that can be added to cosmetics as antimicrobial formulations. This inclusion complex can effectively improve the antibacterial effect of cosmetics or personal care products. For example, andrographolide acetylated derivatives (AcAND) were used to form CD-inclusion complexes with 2-hydroxypropyl-β-cyclodextrin (HPβCD). As an antibacterial formula, this inclusion compound can be added to some toothpastes to effectively destroy bacterial cell walls and cell membranes, significantly improving the antibacterial ability of AcAND and the antibacterial effect of toothpastes ^[1].

CDs can encapsulate antioxidant compounds containing phenolic hydroxyl groups. The phenolic hydroxyl groups in the antioxidant compounds can form hydrogen bonds with the hydroxyl groups in CD, thereby improving the free radical scavenging ability of antioxidant compounds. Therefore, CD-antioxidant inclusion complexes can be added to cosmetics as an anti-aging formula to enhance anti-aging effects. For example, resveratrol is a phytoalexin extracted from plants and has good antioxidant properties. The inclusion complex of HPβCD and resveratrol can greatly improve the antioxidant properties of resveratrol, making it a cosmetic formula that can effectively improve the anti-aging effect ^[1].

CD can also establish a controlled release system for fragrances. It is possible for the free fragrances to evaporate quickly when in contact with the air, thus losing their aromatic odor. By forming inclusion complexes with CD, fragrance molecules can be controlled to release in a dynamic manner. For example, when the CD-fragrance inclusion complex is added to a cosmetic product, the fragrances encapsulated in the CD cavity will be released as the concentration of free fragrances decreases, extending its use time ^[2].