Preparation And Evaluation Of PAG Liposome

Triptolide (TP) has good anti-tumor activity and anti-inflammatory effect, but italso has serious side effects, thereby the clinical use was limited. Low watersolubility and low bioavailability are the toxicity reason. To solve this thorny problem,our research aims at using water-soluble polymer as a carrier, prepare a higherlipid-water partition coefficient prodrug-triptolide poly peptide (TP-PAG) withoutaffecting its pharmacological activity. This study includes the following four parts:(1) Establish the analytical methods of TP-PAGTake triptolide as the measurement indicator, we established the highperformance liquid chromatography (HPLC) method to analyze TP-PAG, OptimalHPLC method conditions are: the mobile phase: acetonitrile-water (25:75); flow rateis1.0mL·min-1; detection wavelength is215nm. Triptolide showed a good linearitywithin a range of0.226~2.262mg·mL-1, the linear curve is A=2803.5C+19167(r2=0.9998). The method is accurate and simple, shows good reproducibility, highsensitivity.(2) Synthesis of TP-PAGFirstly, we synthesized poly peptide with raw materials of L-Asp and L-Glu. Later,we combined poly peptide with TP to form TP-PAG. In order to greatly improveproduct yield and purity, we conducted orthogonal experiments to find out theoptimal condition of benzyl synthesis. We also characterized each product by FTIRand1H-NMR, and the results indicated that TP-PAG was successfully synthesized.(3) Stability and activity of TP-PAGBy TP-PAG stability study and its preliminary activity study against tumor cells,we found that TP-PAG solubility in water was1.45g/100mL, and TP-PAG showedgood stability in pH6.8phosphate buffer solution, pH7.4phosphate buffer anddistilled water. However, it could only be stable in0.1mol/L HCl for12hours, whichmean that its content would decrease after12hours. The preliminary activity studyagainst tumor cells indicated that TP-PAG has good inhibition against the growth ofhuman hepatoma Bel-7402cells.(4) Preparation and Evaluation of TP-PAG liposomesTake the Encapsulation efficiency as key indicator, we found that the reverseevaporation method is the optimal method to prepare TP-PAG liposomes by comparing four preparation methods and they are ether injection method, ethanolinjection method, film dispersion-freeze-thaw method and reverse evaporationmethod. After that, we conducted orthogonal experiments to find out the optimalcondition of reverse evaporation method and the optimal condition is: PC-Chol (2:1),TP dosage is15mg and the temperature is45℃. Investigated shape of TP-PAGliposomes, leakage rate, vitro release rate and stability, we found that TP-PAGliposomes is stable at4℃and could be easily preserved.Conclusion: The synthesized TP-PAG was stable, water-soluble and showed goodinhibition in vitro against human liver cancer cell growth. TP-PAG liposome wasstable at relatively low temperatures. This research provided a good prospect for thedevelopment of anticancer drugs.