Strontium/Birabresib-loaded bioactive glass modulating bone microenvironment for osteoporosis therapy

• Bir@Sr-MBG nanocomposite achieves sustained release of Birabresib for over 168 hours, with high encapsulation efficiency (44.82%) and drug loading (7.47%). • The material exhibits excellent cytocompatibility and superior anti-inflammatory effects by shifting macrophage polarization from M1 to M2 phenotype, reducing pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and increasing anti-inflammatory IL-4. • Bir@Sr-MBG significantly inhibits osteoclast differentiation and promotes osteogenic differentiation of bone marrow mesenchymal stem cells under inflammatory conditions, outperforming Sr-MBG or Birabresib alone. • The dual-action mechanism of strontium ions and Birabresib offers a promising therapeutic strategy for osteoporosis, especially in cases with concurrent inflammation.