*5.1.1 Antimicrobial and antibiotics*

Several reviews exist about systems developed for the treatment of infections. Specifically, in Ref. [100], the most important works concerning the use of lipidbased formulations from 2000 to 2020 are compiled. Infections caused by bacteria resistant to antimicrobial drugs available for use in humans have increased exponentially. This revision highlights the importance of the development of nanotechnology in lipid systems as an innovative tool for infection treatment. Chitosan nanocapsules, and lecithin-polysorbate 80, containing dapsone, have resulted useful; also, lipid nanocapsules with carvacrol and cinnamaldehyde. Another review about the incorporation of natural substances with antimicrobial activity in polymeric nanoparticles highlights specifically the antifungal activity against *Candida* species of *Glycyrrhiza glabra L.*, which is included in mucoadhesive nanoparticles constituted by PLA, PLGA, and alginate. Nanocapsules were also prepared from polymyxin B cross-linked with sodium alginate and solid lipid nanoparticles with *Ginkgo biloba L.*, and their antimicrobial activity against *Pseudomonas aeruginosa* was studied [101]. For the delivery of fluoxetine, starch nanocapsules with core-shell morphology were prepared and joined to polyurethane. The system presented antibacterial activity against *Staphylococcus aureus* [54]. The incorporation of antimicrobial peptides appears as a promising alternative for infection treatment, as well as carvacrol loaded onto nanocapsules formed by PCL [55]. PCL nanocapsules loaded with amoxicillin trihydrate were prepared to investigate the gastric stability of this drug, as well as its therapeutic activity against *H. pilori* [56]. Eudragit® polymers (polymethacrylate-based copolymers) are easy to handle and are used to prepare formulations for oral administration. Antibiotic florfenicol was encapsulated in Eudragit® nanocapsules [57].

Besides, it was possible to demonstrate the antimicrobial activity of chitosan against *Escherichia coli* through the assembly of bacteria cell membranes. This last finding represents an advance in delivery systems based on chitosan nanocapsules since it can enhance the effects of carried antibiotics [102]. As a strategy to increase the solubility of capsaicin, a major component of chili peppers known for its numerous therapeutic activities, nanocapsules of chitosan in the form of high-payload submicron capsaicin-chitosan colloidal particle complex were prepared. Besides

