Advances in injectable drug delivery systems for the treatment of rheumatoid arthritis.

Rheumatoid arthritis is a chronic autoimmune disease characterised by inflammation and progressive joint damage, necessitating innovative therapeutic strategies. Conventional rheumatoid arthritis treatments, including disease-modifying antirheumatic drugs, nonsteroidal anti-inflammatory drugs, glucocorticoids, and biologics, often administered through systemic or intra-articular ways. These drugs often have low accumulation and/or retention in articular cartilage, causing dose-limiting toxicities and reduced efficacy. This review summarises recent advances in injectable drug delivery systems, specifically hydrogels, microspheres, and nanoparticles, highlighting their potential to enhance rheumatoid arthritis therapy. The outstanding potential of these systems was demonstrated; however, substantial research remains to be conducted to optimise their performance and safety.