Preparation And In Vitro Activity Evaluation Of Paclitaxel Redox Nanoparticles

Paclitaxel is a natural antitumor drug extracted from Taxus mairei,a rare anticancer plant all over the world.It has a good antitumor effect on breast cancer,ovarian cancer,uterine cancer and so on,which has attracted much attention since it came out,as a first-line antineoplastic drug.However,paclitaxel itself has strong toxicity,causing great toxic and side effects on human body,and poor water solubility,slow dissolution rate and other shortcomings greatly limit the clinical application of paclitaxel.Therefore,improving the water solubility of paclitaxel and reducing its toxic and side effects has been a hot research direction.In this paper,polyethylene glycol-deoxycholic acid(mPEG-DCA),which has good biocompatibility,was linked with paclitaxel(PTX)through disulfide bond,and PTX was used as stabilizer to prepare paclitaxel nano-suspension again as model drug,in order to improve the solubility and increase the drug loading.In this study,polyethylene glycol-deoxycholic acid(mPEG-DCA)and paclitaxel(PTX)were linked by disulfide bond as stabilizer to prepare paclitaxel nano-suspension.Paclitaxel nano-suspension was prepared by microprecipitation method,ultrasonic and microprecipitation-high pressure homogenization method.The effect of the ratio of stabilizer to drug on the stability of paclitaxel nano-suspension was investigated.Finally,the optimum formulation and preparation process were determined.The results of differential scanning(DSC)and X-ray diffraction showed that paclitaxel in nano-suspension existed in amorphous form,which was beneficial to the rapid dissolution of the drug.In the redox sensitivity test,the change trend of particle size of suspension MDCP in the presence of glutathione(GSH)was consistent with that in the absence of GSH.That is to say,the particle size did not change obviously.The suspension MDSP has redox sensitivity due to the presence of disulfide bonds,and the particle size of the suspension increases obviously in the presence of GSH,indicating that the suspension MDSP reacts to a certain extent under the action of GSH and the structure of the suspension is destroyed,causing the particle size to become larger.In the vitro release test also confirmed that the suspension MDSP had redox sensitivity,but the suspension MDCP had no redox sensitivity.From the results of in the vitro release,it can be seen that the release rate and total amount of MDSP in the dissolution medium containing reductant(DTT)are 1.8 times higher than those of the suspension MDCP.In the control group,the dissolution rate and total release of MDCP were consistent regardless of the presence or absence of reductant in the dissolution medium.The results of plasma stability test showed that the particle size of the two suspensions in the medium containing 10%FBS did not change much,but on the whole,the stability of MDSP was better than that of MDCP.Protein adsorption test showed that the two suspensions did not occur protein adsorption phenomenon,indicating that the two suspensions may not destroy red blood cells and hemolysis when they enter the body.It can be seen that both suspensions show good biosafety,good plasma stability,do not adsorb proteins after entering the body,and do not destroy red blood cells in the blood.The above results showed that the suspension was suitable for intravenous administration.The cytotoxicity of the two suspensions in vitro was studied.the cell survival rate of the preparation was compared with that of the control preparation by MTT assay,and the IC(50)value was calculated.The results showed that the preparations in each group showed concentration-dependent and time-dependent in two different cells.Due to the presence of disulfide bonds in MDSP group and MDSP+GSH group,when they entered tumor cells,the bond was broken under the action of higher GSH of tumor cells,which released more PTX to kill tumor cells and showed better cytotoxicity.However,MDCP group and MDCP+GSH group did not produce similar results because there was no disulfide bond.This is consistent with the results of in vitro release and redox sensitivity studies.The cytotoxicity of free paclitaxel(PTX)was the smallest in both cells,and the cytotoxicity of suspension MDSP was the maximum.It can be seen that the suspension increased the uptake of drugs by cells,thus showing better cytotoxicity.