Demeng Xia,1,2,* Qingqing Qian,1,* Sheng Wang,3,* Xiao Dong,4 Ying Liu5 

1Department of Pharmacy, The Fifth People’s Hospital of Shanghai, Fudan University, Shanghai, 200240, People’s Republic of China; 2Department of Pharmacy, Seventh People’s Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, 200120, People’s Republic of China; 3Department of Traumatic Orthopedics, Shanghai Fourth People’s Hospital, School of Medicine, Tongji University, Shanghai, 200434, People’s Republic of China; 4School of Medicine, Shanghai University, Shanghai, 200444, People’s Republic of China; 5Institute of Translational Medicine, Shanghai University, Shanghai, 200444, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Ying Liu; Xiao Dong, Email liuchanger1984@163.com; dong-xiao@shu.edu.cn

Introduction: Osteoporosis, characterized by dysregulation of osteoclastic bone resorption and osteoblastic bone formation, severely threatens human health during aging. However, there is still no good therapy for osteoporosis, so this direction requires our continuous attention, and there is an urgent need for new drugs to solve this problem.
Methods: Traditional Chinese Medicine Salvia divinorum monomer pomolic acid (PA) could effectively inhibit osteoclastogenesis and ovariectomized osteoporosis. However, its poor solubility and lack of targeting severely limits its further application. A novel bone-targeting nanomedicine (PA@TLipo) has been developed to reconstruct the osteoporotic microenvironment by encapsulating pomolic acid in alendronate-functionalized liposomes. Through a series of operations such as synthesis, purification, encapsulation, and labeling, the PA@TLipo have been prepared. Moreover, the cytotoxicity, bone targeting and anti-osteoporosis effect was verified by cell and animal experiments.
Results: In the aspect of targeting, the PA@TLipo can effectively aggregate on the bone tissue to reduce bone loss, and in terms of toxicity, PA@TLipo could increase the bone target ability in comparison to nontargeted liposome, thereby mitigating systemic cytotoxicity. Moreover, PA@TLipo inhibited osteoclast formation and bone resorption in vitro and reduced bone loss in ovariectomy-induced osteoporotic mice.
Conclusion: In this study, a novel therapeutic agent was designed and constructed to treat osteoporosis, consisting of a liposome material as the drug pocket, PA as the anti-osteoporosis drug, and ALN as the bone-targeting molecule. And our study is the first to employ a bone-targeted delivery system to deliver PA for OVX-induced bone loss, providing an innovative solution for treating osteoporosis.

Keywords: bone targeting, alendronate functionalized liposome, pomolic acid, osteoporosis therapy