*Article* **Dexamethasone-Loaded Lipomers: Development, Characterization, and Skin Biodistribution Studies**

**Eloy Pena-Rodríguez, Maria Lajarin-Reinares, Aida Mata-Ventosa, Sandra Pérez-Torras and Francisco Fernández-Campos**


**Abstract:** Follicular targeting has gained more attention in recent decades, due to the possibility of obtaining a depot effect in topical administration and its potential as a tool to treat hair folliclerelated diseases. Lipid core ethyl cellulose lipomers were developed and optimized, following which characterization of their physicochemical properties was carried out. Dexamethasone was encapsulated in the lipomers (size, 115 nm; polydispersity, 0.24; zeta-potential (Z-potential), +30 mV) and their in vitro release profiles against dexamethasone in solution were investigated by vertical diffusion Franz cells. The skin biodistribution of the fluorescent-loaded lipomers was observed using confocal microscopy, demonstrating the accumulation of both lipomers and fluorochromes in the hair follicles of pig skin. To confirm this fact, immunofluorescence of the dexamethasone-loaded lipomers was carried out in pig hair follicles. The anti-inflammatory (via TNFα) efficacy of the dexamethasone-loaded lipomers was demonstrated in vitro in an HEK001 human keratinocytes cell culture and the in vitro cytotoxicity of the nanoformulation was investigated.

**Keywords:** follicular targeting; dexamethasone; alopecia areata; lipomers; lipid polymer hybrid nanocapsules; biodistribution; skin; ethyl cellulose
