Microalgae‐Based Dual Drug Delivery System with Enhanced Articular Cavity Retention for Osteoarthritis Treatment

Abstract Osteoarthritis (OA) is a prevalent degenerative joint disease globally, and the availability of effective treatments for OA remains limited. Recent research has shown that metformin offers pleiotropic advantages in the development of OA. However, the therapeutic effects of metformin are hindered by inadequate residence time within the joints, instability, and low bioavailability. In this study, the utilization of natural microalgae S. platensis (SP) is proposed as carriers for metformin, resulting in the development of a metformin delivery system (SP@Met) as a dual drug delivery system that exhibits responsive dual drug cascade release and improved retention within the articular cavity. The local administration of SP@Met has demonstrated efficacy in extending the drug retention time within the articular cavity, while also enabling cascade release of both metformin and phycocyanin. SP@Met can effectively eliminate reactive oxygen species, reduce the expression of pro‐inflammatory cytokines, and restore the balance of cartilage anabolism and catabolism, thereby impeding the progression of OA. This therapeutic approach utilizes a natural microalgae carrier to facilitate efficient delivery of metformin to the articular cavity, resulting in synergistic therapeutic efficacy and offering a promising avenue for the management of OA for potential clinical application.