Single dose erythromycin Derived Microparticles Enhance Bone Regeneration and Periodontal Health: Study

Erythromycin (ERM) has demonstrated therapeutic potential in promoting alveolar bone regeneration by enhancing developmental endothelial locus 1 (DEL-1) activity in periodontitis. Because this regenerative effect requires sustained local exposure at low, controlled doses, formulating ERM into microparticles can help deliver the drug directly to periodontal tissues while maintaining its therapeutic concentration over time. This study introduces a novel intrapalatal injection strategy for ERM-loaded microparticle delivery, to enhance bone regeneration and maintain periodontal health by activating endogenous DEL-1 signaling, supporting the potential of these formulations as pocket-injectable, bone-regenerative agents.

ERM-loaded nano- and microparticles were prepared using biodegradable polymers—poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA)—with varying lactic/glycolic ratios and molecular weights. Four formulations (SP0073-1 to SP0073-4) were produced by an oil-in-water emulsion solvent evaporation method, with ERM concentrations (12–16%). Ligature-induced periodontitis was created in 8-week-old male C57BL/6J mice, followed by a single intrapalatal injection of ERM formulations or blank particles.

Mice were sacrificed after 9 or 21 days for histological evaluation using alkaline phosphatase and tartrate-resistant acid phosphatase staining. DEL-1 expression was assessed by immunofluorescence, and RNA-seq analysis of gingival tissue identified bone regeneration-related gene expression. The effects of ERM, blank particles, and ERM-loaded nano- and microparticles on osteogenic activity were assessed in MC3T3-E1, human periodontal ligament, and mouse bone marrow cells.

Among ERM-loaded microparticles, SP0073-4 significantly upregulated Edil3, Bglap2, Sp7, and Col5a1 expression, increased DEL-1 and osteocalcin expression in periodontal tissue, and preserved alveolar bone in young mice while promoting bone growth in aged mice. SP0073-4 enhanced osteoblast activity, reduced osteoclastogenesis, and increased mineralisation compared with ERM alone.

ERM-based microparticles (SP0073-4) promote bone regeneration and maintain periodontal integrity by activating DEL-1 signaling and modulating bone remodeling dynamics.

Reference:

Meircurius Dwi Condro Surboyo, Prasiddha Mahardhika El Fadhlallah, Kridtapat Sirisereephap, Yurie Sato-Yamada, Fang Meiwen, Yamauchi Mizuki, Nagako Yoshiba, Koichi Tabeta, Yutaka Terao, Andrea Rosenkranz, Takeyasu Maeda, Ryo Takabatake, Hirofumi Miyaji, Hiroshi Takemoto, Tomoki Maekawa. Single-dose intrapalatal injection of erythromycin-loaded microparticles mitigates periodontitis-induced alveolar bone loss and enhances bone regeneration, International Journal of Pharmaceutics, 2026, 126995, ISSN 0378-5173. https://doi.org/10.1016/j.ijpharm.2026.126995.