SYN321

SYN321 is a novel conjugate of diclofenac and chemically modified sodium hyaluronate (NaHA), designed for slow and sustained intra-articular (IA) release within the joint. Developed by Synartro, it is in clinical development for the treatment of symptomatic knee osteoarthritis. The mechanism combines the anti-inflammatory and analgesic properties of diclofenac with the viscoelastic and potential lubricating effects of hyaluronic acid, aiming to reduce local inflammation, decrease cartilage matrix degradation (including MMP13 downregulation), and minimize systemic exposure to diclofenac. Preclinical models demonstrate reduced OA-related inflammatory responses and improved safety and tolerability compared with unbound diclofenac and HA, with minimal systemic absorption after IA administration[1][2][3][5][9].