Preliminary Study On Co-loading Of Docetaxel And Gambogic Acid Albumin Nanoparticles

Gastric cancer is one of the most common diseases in the world and has become a serious public health problem worldwide.Among them,gastric cancer is the second leading cause of cancer-related death in China,and the incidence is on the rise.At present,surgical resection,chemotherapy or radiotherapy are mostly used to treat gastric cancer,but the survival rate within 5 years after treatment is still less than 20%.Tumors have a certain adaptability and resistance to a variety of cytotoxic drugs,which is also the main reason for the failure of chemotherapy-multidrug resistance?MDR?.The application of nanotechnology in reversing MDR is a frontier topic in the research of new drugs nowadays.Nanotechnology seeks to use drug delivery carriers with a diameter of 1-100 nm,which consist of several different materials to deliver anti-cancer drugs to cancer cells and overcome MDR.Docetaxel?DTX?,an intermediate product in the synthesis of paclitaxel,is a taxane anticancer drug approved by the Food and Drug Administration of the United States in 1998.Gambogic acid?GA?is a natural compound with cage-like oxygen-anthraquinone structure,and is one of the effective components secreted by Gamboge.Pre-clinical studies have shown that GA has anti-cancer properties against a variety of malignant tumors,including solid and hematological cancers,but is resistant to normal human cells.GA can restore the sensitivity of gastric cancer cell lines to DTX by inhibiting the expression of survivin.GA can also sensitize gastric cancer cells to DTX by down-regulating survival protein expression and inducing apoptosis.In gastrointestinal cells,GA plays an important role in sensitizing gastrointestinal cells by inhibiting the expression of DTX-induced apoptosis-related genes such as beta-tubulin III,tau and survivin.In addition,because of the poor water solubility of DTX and GA,most of the injections are administered with auxiliary solvents,but the auxiliary solvents are viscous and hemolytic.In clinical trials,most of the patients will have irritative and allergic reactions.Therefore,a new formulation was developed to improve the solubility of DTX and GA in water,reduce the toxicity and adverse reactions caused by solvents.At the same time,GA combined with DTX could improve the efficacy of drugs and overcome MDR.Bovine serum albumin has become a hotspot in the research of new drug delivery systems in recent years because of its higher therapeutic index and safety,and can significantly reduce adverse reactions compared with cosolvents.Firstly,in this study,a method for the determination of docetaxel and gambogic acid by high performance liquid chromatography in vitro was investigated.The linear equation of DTX is Y=681547X-20446?R2=0.9999?,and the linear range is from 4.404 to 22.02 ug.The linear equation of GA is Y=1.693×106X-3.076×106?R2=0.9992?,and the linear range is 4.004²0.02 ug.All the methodological parameters met the requirements of drug content determination.It provides conditions for the determination of encapsulation efficiency and in vitro release of drug-loaded albumin nanoparticles by HPLC in subsequent experiments.At the same time,the in vitro release of DTX and GA preparations was studied,which provided a reliable basis for the subsequent determination of the in vitro release and entrapment efficiency of DTX and GA preparations.Docetaxel and gambogic albumin nanoparticles suspensions were prepared by Nab^TM method.The best oil ratio was dichloromethane:ethanol=2:1.Star design-response surface methodology was used to screen out the optimal prescription for BSA concentration of 5 g·L^-1,water-oil volume ratio?water-oil volume ratio?=1:17,drug-load ratio?drug-carrier mass ratio?=1:10.The prepared DTX-GA-BSA NPs suspension has an average particle size of 135.8 nm,PDI=0.09,Zeta potential-21.4 mV and a uniform transparent yellowish appearance.Therefore,the average particle size of DTX-GA-BSA NPs suspension is small,and its distribution is narrow and uniform.In this study,low differentiated human gastric cancer cells MGC-803 and differentiated human gastric cancer cells HGC-27 were selected as model cells.Drug interaction index?CDI?was used to analyze the synergistic effect of DTX and GA.The optimal synergistic ratio of DTX and GA was obtained through screening.In vitro cell experiments showed that DTX and GA had synergistic effects on the proliferation inhibition of human gastric cancer cells,and PTX:TMZ=1:23?w/w?had the strongest synergistic inhibition on MGC-803 cells,while PTX:TMZ=1:195?w/w?had the strongest synergistic inhibition on HGC-27 cells.In conclusion,DTX-GA-BSA NPs prepared in this experiment have smaller particle size,better stability and can delay drug release.The optimized formulation of DTX-GA-BSA NPs is stable and reliable,and the established mathematical model has good predictive ability and practicability.These provide a new and effective strategy for the research of DTX and GA new drug delivery systems.In addition,on this basis,in vitro cell experiments proved that DTX and GA had synergistic inhibition on MGC-803 cells and HGC-27 cells.CDI was used to analyze the synergistic effect of DTX and GA,and the optimal synergistic ratio of DTX and GA was screened.The synergistic action of DTX-GA-BSA NPs against gastric cancer in vitro will be further studied.DTX and GA will be co-loaded into nanoparticles at the optimal synergistic ratio.The synergistic effect of DTX and GA in DTX-GA-BSA NPs against human gastric cancer cells in vitro will be further evaluated,and whether the drugs carried by BSA can play a better role in the treatment of gastric cancer.