Sustained release of betamethasone from solid lipid nanoparticles loaded polymeric hydrogels with natural emollient: One step closer to effective topical therapy for atopic dermatitis

Atopic dermatitis (AD), an inflammatory skin disease, has persisted as a global burden for decades. The existing therapy lacks multitargeted formulations, is ineffective, and bears adverse effects. Consequently, it offers limited relief from pruritus and inflammation, impacting both the patients' quality of life as well as health care systems. We hypothesize that localized therapy comprising natural emollients offers better therapeutic outcome and superior acceptability. Herewith, we propose the novel hydrogel formulations for multipurpose treatment that utilizes lipid nanoparticles with model drug betamethasone dipropionate (BMS), that are incorporated in gel formulation comprising a natural emollient, coconut oil. BMS-solid lipid nanoparticles (BMS-SLNs), optimized for size and drug load, were embedded in three different hydrogels, all comprising coconut oil as an emollient. Chitosan, alginate, and carbomer were selected as hydrogel-forming material. The nanocarriers-in-hydrogel formulations were evaluated through BMS permeation in human skin as well as their physicochemical properties including viscosity, stability, texture, rheology and pH. Preliminary in vitro and ex vivo studies demonstrated that all hydrogel formulations prolonged BMS release up to 24 h. All formulations were found to be safe as confirmed by in vitro cytotoxicity assay. The novel nanocarrier-in-hydrogel formulations hold promise as an effective therapeutic strategy for AD management.