Dexamethasone-loaded implants enhance antirheumatic efficacy in an adjuvant-induced arthritis rat model

Dexamethasone (DEX) is a cornerstone drug in the clinical management of rheumatoid arthritis (RA). Nonetheless, its therapeutic efficacy is hampered by systemic side effects and poor tissue specificity. In this study, a release system was developed based on poly (lactic-co-glycolic acid) (PLGA) for the delivery of DEX-loaded implants for localized and sustained drug delivery. In an adjuvant-induced arthritis rat model, peri-articular implantation of DEX-loaded implants markedly alleviated joint swelling, suppressed synovial hyperplasia, and reduced articular inflammation. The treatment also downregulated key proinflammatory cytokines, including TNF-α, IL-1β, and IL-6, demonstrating superior antirheumatic efficacy compared with oral administration. Pharmacokinetic studies confirmed that the implants exhibited sustained release profiles both in vivo and in vitro. Furthermore, Fourier transform infrared (FTIR) spectroscopy verified the favorable compatibility between the drug and excipients. These findings indicated that PLGA-based DEX implants enhance therapeutic efficacy while minimizing systemic toxicity, thereby providing an effective and safe therapeutic strategy for treating RA.