**4. Conclusions**

The aim of this article was to review the literature about the development of new systems for loading AST for cosmetics and topical usage. Delivery systems are useful for the improvement of the physicochemical profile of this compound, such as stability, watersolubility, antioxidant properties, drug release, and in vivo and in vitro biological activities. Therefore, the delivery systems for loading AST described in this article create opportunities for industrial applications; however, other industrial issues for the development of new products must be evaluated. Moreover, AST-optimized products become potentially attractive for the development of further studies, due to the antioxidant properties and benefits of AST.

**Funding:** This research was funded by in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).

**Acknowledgments:** The authors thank CNPq and CAPES for their support and Federal University of Rio Grande do Norte.

**Conflicts of Interest:** The authors declare no conflict of interest. CNPq and CAPES have no role in the design of the study, in the collection, analyses or interpretation of data, in the writing of the manuscript, or in the decision to publish it.
