Cyclodextrin Applications in the Cosmetic Industry: A Review

The cosmetic industry is constantly evolving to create new formulations that offer controlled and specific release of active ingredients, as well as greater penetration, duration and stability of the resulting products. To fulfil all these objectives, the use of cyclodextrins in different cosmetic formulations is being considered. CDs are cyclic oligosaccharides with a hydrophilic outer surface and an inner cavity able to encapsulate hydrophobic molecules. This property can be used to form complexes with hydrophobic molecules and solubilise them in aqueous matrices, such as creams or gels. This review analyses the main advantages that these agents provide in cosmetic products, such as protection, administration and controlled release of bioactive ingredients, improved water solubility, reduced fragrance volatility, masking off unpleasant odours, modification of the physicochemical properties of formulations or prevention of ingredient side effects, among others. Formulations of lotions, sunscreens, deodorants, gels or perfumes containing CDs are already on the market, and new ones are being developed. Moreover, the regulations concerning their use, the types of cyclodextrins allowed and the mechanism required to produce CD-guest inclusion complexes are reviewed. Likewise, the use of CDs alone or encapsulating other compounds makes them an extremely versatile nanomaterial for dermofacial and cosmetic formulations.