Adhesive Composite Hydrogel Patch for Sustained Transdermal Drug Delivery To Treat Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Continuous administration of steroids often causes undesired side effects; hence, drug delivery systems with high loading capacities and sustained release profiles are required. Herein, adhesive hydrogels for sustained transdermal delivery of dexamethasone (DEX), a potent corticosteroid, have been suggested for AD treatment. The adhesive composite hydrogels comprise a double network of polyacrylamide (PAM) and polydopamine (PDA) embedded with extra-large-pore mesoporous silica nanoparticles (XL-MSNs). The intrinsic skin adhesiveness of the dopamine-derived PAM/PDA hydrogels is further enhanced by XL-MSN incorporation that contributes to the simultaneous enhancement of cohesion and adhesion of the hydrogel. The resulting adhesive hydrogels exhibit a high water content and strong adhesion to porcine skin. A sustained release of DEX is obtained when DEX is loaded within the pores of XL-MSNs in PAM/PDA hydrogels compared to the rapid release from the direct loading of DEX in hydrogels. Application of DEX-loaded MSN@PAM/PDA hydrogels on an AD mouse model led to the significant suppression of AD symptoms, including the restoration of the thickened epidermal layer, decrease in inflammatory cell infiltration in the skin, recovery of collagen deposition, and decreased levels of immunoglobulin E. XL-MSN-embedded adhesive hydrogels could be a potential platform for topical drug delivery to treat inflammatory skin diseases.