Natural Polymer-Based Microspheres For Anti-Inflammatory Drug Delivery : Materials, Characterization, and Therapeutic Applications

Abstract

Microsphere-based drug delivery systems have gained considerable attention in pharmaceutical research due to their ability to provide controlled, targeted, and sustained release of therapeutic agents while minimizing systemic side effects. In particular, microspheres formulated from natural polymers such as chitosan, sodium alginate, pectin, and gelatin have emerged as promising carriers for anti-inflammatory therapy owing to their biocompatibility, biodegradability, low toxicity, and responsiveness to physiological stimuli. This review comprehensively discusses the role of natural polymer–based microspheres in inflammatory drug delivery, focusing on polymer characteristics, preparation methods, release and delivery mechanisms, and routes of administration. Emphasis is placed on their application in both in vitro and in vivo anti-inflammatory models, including carrageenan-induced paw edema, lipopolysaccharide-induced inflammation, and monosodium iodoacetate–induced osteoarthritis. Evidence from preclinical studies demonstrates that these systems are capable of enhancing drug stability, prolonging residence time at the inflamed site, modulating inflammatory mediators such as TNF-α, IL-1β, and IL-6, and improving overall therapeutic efficacy compared with free drugs. Despite these advantages, challenges related to polymer variability, mechanical stability, release precision, and large-scale production remain. Future advancements in polymer modification, hybrid polymer systems, and advanced fabrication technologies are expected to further optimize natural polymer-based microspheres, supporting their potential application in personalized and long-term inflammatory therapy.