A Long‐Acting and Sustained‐Release Poly (L‐Lactic Acid) Microsphere System Containing Naringin: Fabrication and In Vitro Bone Modification

ABSTRACT Poly (L‐lactic acid) (PLLA) is a biocompatible and safe polymer, making it an ideal material for fabricating microspheres for drug delivery. In this study, naringin, which a role in bone modification, is used as the active pharmaceutical ingredient, and PLLA is employed as the drug carrier to fabricate naringin‐loaded PLLA microspheres, thereby creating a long‐acting, sustained‐release drug delivery system. The ideal microspheres are prepared by stirring at 200 revolutions per minute for 8 hours. Compared to other microsphere materials, PLLA microspheres achieved an encapsulation efficiency of up to 70%. Moreover, this study provides the first demonstration of acid‐enhanced sustained naringin release via PLLA microspheres, which ensures continuous drug release for over 35 days, with a release rate of 50%. The kinetics of drug release confirmed the sustained release profile of the system. In vitro experiments revealed that naringin‐loaded PLLA microspheres maintained a cell survival rate of over 95% for L929 cells, significantly higher than that of free naringin. Furthermore, naringin‐loaded microspheres effectively promoted the growth and differentiation of bone marrow mesenchymal stem cells (BMSCs). These findings highlight the potential application of naringin‐loaded PLLA microspheres in bone repair, offering a promising strategy for sustained drug delivery in biomedical applications.