Objective To determine the solubility and apparent oil/ water partition coefficient of sitafloxacin in different solvents. Methods High performance liquid chromatography (HPLC) was used. The column was Dikma Diamonsil C18 (2) (4. 6 mmí250 mm,5 μm). The mobile phase was 0. 05 mol·L-1 KH2 PO4 solution (pH was adjusted with H3 PO4 to 2. 4)-acetonitrile (7030). The column temperature was set at room temperature. The flow rate was 1. 0 mL·min-1 . The detection wavelength was 295 nm and the injection volume was 10 μL. The solubility of sitafloxacin and the apparent oil/ water partition coefficient at pH 2. 0,4. 3,5. 8,6. 6,7. 4,8. 0,10. 0 and 11. 2 were determined. Results The equilibrium solubility of sitafloxacin in water was 0. 44 mg·mL-1 and the apparent oil/ water partition coefficient was 0. 23 (lgP= -0. 64) at (37±2) ℃ . Sitafloxacin has the lowest equilibrium solubility (0. 13 mg·mL-1 ) and the highest apparent oil/ water partition coefficient in pH7. 4 buffer solution system. At pH>10 and pH<5. 8,the solubility of sitafloxacin increased obviously and apparent oil/ water partition coefficient decreased. Conclusion Sitafloxacin is insoluble in water and also poorly soluble in oil,but its solubility could be improved significantly in acidic or alkaline solution.

Osteosarcoma (OS) is the most common primary malignant bone tumor in clinic. It has high mortality and disability rate. Effective neoadjuvant chemotherapy combined with limb salvage surgery can improve the 5-year survival rate of OS patients. Drug resistance or low sensitivity of tumor cells is the most common cause of postoperative local recurrence and metastasis. Therefore, the sensitivity of OS cells to chemotherapy drugs is of great value to the prognosis of the patients. In recent years, traditional Chinese medicine has been widely used because of high efficiency and low toxicity. A large number of studies have confirmed that part of traditional Chinese medicine can reverse the chemotherapy resistance of OS cells by regulating the ABC transmembrane transport protein system. This article gives an overview of its related mechanisms and latest developments.

Osteosarcoma， a common primary bone malignancy， features high heterogeneity， poor prognosis， high propensity for local invasion and distant metastasis， and high mortality. At the moment， the major therapy is the combination of neoadjuvant chemotherapy and limb salvage surgery， which remarkably reduces the disability rate and fatality rate. However， long-term use of chemotherapeutic drugs leads to the acquisition of drug resistance by osteosarcoma cells and reduces the sensitivity of the tumor cells to the drugs. Thus， this therapy is not satisfactory. In recent years， amid the advancement in the treatment of tumor， Chinese medicine has attracted extensive attention for the obvious therapeutic effect and few adverse reactions. Phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） /mammalian target of rapamycin （mTOR） signaling pathway， as a classic cancer signaling pathway， is abnormally activated in osteosarcoma cells， which affects the proliferation， invasion， and metastasis of osteosarcoma cells by influencing the cycle of tumor cells， inhibiting apoptosis and autophagy of tumor cells， and promoting tumor angiogenesis. According to clinical research， Chinese medicine monomers influence proliferation， apoptosis， and autophagy of osteosarcoma cells and angiogenesis by regulating the activity of proteins in PI3K/Akt/mTOR signaling pathway， thereby suppressing osteosarcoma tissues and cells. Moreover， they can reverse the resistance of tumor cells to multiple anticancer drugs. Based on the knowledge and experience of Chinese medicine in the treatment of osteosarcoma， this paper reviews the role of PI3K/Akt/mTOR signaling pathway in the treatment of osteosarcoma by Chinese medicine monomers， which is expected to serve as a reference for the application of Chinese medicine in the treatment of osteosarcoma.