Sprayable Hydrogel-Mediated Ultrasound Transdermal Drug Delivery for Gouty Arthritis Treatment

Gouty arthritis (GA) is an acute inflammatory joint disease characterized by severe pain and recurrent attacks. Current local therapies are limited by the invasiveness of intra-articular injection or the poor efficiency of conventional transdermal drug delivery. Although ultrasound-mediated transdermal delivery enhances skin permeability noninvasively, conventional coupling agents require removal after treatment and cannot sustain local drug release. Herein, we report an ultrasound-assisted sprayable hydrogel that replaces conventional coupling agents and enables sustained local drug delivery. Rapid ionic crosslinking of sodium alginate (SA) with Ca2+ forms a colchicine-loaded depot. Ultrasound enhances transdermal penetration and accelerates drug release, while the residual hydrogel sustains release after treatment. In vivo, the platform alleviates joint swelling, suppresses inflammatory cytokines, preserves bone architecture, and improves motor function in gouty arthritis. This noninvasive platform offers a potential therapeutic strategy for gouty arthritis and other inflammatory musculoskeletal disorders.