| Objectives: At present,the main way of administration of cabazitaxel is intravenous drip.Due to the poor solubility of cabazitaxel,Tween80 is needed to increase the solubility of the drug,but solvent enhancement usually produces some side effects,such as neutropenia,mucositis,etc.Oral administration can improve safety,patient compliance,and the possibility of at-home chemotherapy.In order to achieve oral administration of cabazitaxel,it is necessary to improve its water solubility,ensure that it is not degraded in the gastrointestinal tract and increase the intake of intestinal epithelial cells.A cabazitaxel-loaded polymer-lipid hybrid nanoparticle modified with ursodeoxycholic acid(UDCA)was designed to solve the above problems.PCL was selected as the core material,F68 and phospholipid were selected as the surfactants.PCL can load lipophilic drugs and has strong structural characteristics.Nanoparticles prepared with PCL as the core can improve the solubility and stability of cabazitaxel in gastrointestinal environment.Phospholipids as excipients can improve the drug loading capacity and encapsulation rate of lipophilic drugs.UDCA is modified to the surface of nanoparticles by means of its amphiphilic properties,so that nanoparticles can target sodium-dependent bile acid transporters(ASBT),and the drug uptake by intestinal epithelial cells can be improved through the ASBT-mediated transprot process.ASBT has high affinity and high capacity for substrates.Methods: Based on Ch P and related literature,the in vitro analysis method of cabazitaxel was established by high performance liquid chromatography(HPLC).The nanoparticles were prepared by the emulsion solvent evaporation method,and the final prescription dosage and preparation process were determined by single factor investigation and comprehensive testing.The in vitro stability test and in vitro release experiment were carried out to investigate the protective ability and release behavior of nanoparticles to loaded drugs in simulated gastrointestinal environment.In order to study the uptake of nanoparticles by intestinal epithelial cells,human colon adenocarcinoma cells(Caco-2)were used as a model system.The nanoparticles were labeled with fluorescence,and the intracellular fluorescence intensity was measured by flow cytometry to determine the cell uptake of the nanoparticles,and the drug concentration and protein concentration in the cell lysate were measured.The uptake of cabazitaxel-loaded nanoparticles was judged according to the ratio of drug concentration to protein concentration.The above two methods were used to evaluate the cell uptake of nanoparticles and to verify whether UDCA-modified nanoparticles increased cell uptake through ASBT-mediated transport.Results: An in vitro analytical method for the determination of cabazitaxel by HPLC was established.The final formulation and preparation process of nanoparticles were determined by single factor investigation and comprehensive experiment.The optimal prescription was cabazitaxel 1mg,phospholipid 5mg,F68 4mg,UDCA 5mg and PCL10 mg.The cabazitaxel-loaded nanoparticles with UDCA modified polymer-lipid hybrid nanoparticles(CTX-UPLNPs)are spherical or ellipsoidal,the surface has a smooth texture,the particle size is about 176.3±90.29 nm,the surface potential of-27±4.70 m V,and the entrapment efficiency of 99.33%.After 3 hours in simulated gastric fluid,the drug content in CTX-UPLNPs was more than 65% of the initial content,while the drug content in cabazitaxel solution was less than 10% of the initial content.After 6 hours in simulated intestinal fluid,the drug content in CTX-UPLNPs was more than 90% of the initial content,and the drug content in CTX-UPLNPs was less than 10% of the initial content.In simulated gastric fluid and simulated intestinal fluid,cabazitaxel was more stable.The uptake of nanoparticles by Caco-2 cells increased with the increase of time,and the uptake of nanoparticles increased with the increase of nanoparticles concentration.UDCA was used to competitively inhibit ASBT,so that the uptake of CTX-UPLNPs by cells in the inhibition group was reduced to 73.4% of that in the uninhibited group,and inhibition of ASBT could reduce the uptake of CTX-UPLNPs by intestinal epithelial cells.The uptake of CTXUPLNPs by cells was 1.62 times that of unmodified polymer-lipid hybrid nanoparticles(CTX-PLNPs),and the uptake of intestinal epithelial cells can be increased by using UDCA modified nanoparticles.Conclusions: In order to improve the solubility of cabazitaxel,the stability in the gastrointestinal environment and the absorption of intestinal epithelium,CTXUPLNPs were successfully prepared by emulsion solvent evaporation.The particle size was expected to be smaller than 200 nm.The surface potential of CTX-UPLNPs was between-25 m V and-30 m V.Its suspension was not easy to aggregate.CTXUPLNPs used PCL as the core to solve the problem of poor water solubility of cabazitaxel.In simulated gastric fluid and simulated intestinal fluid,the content of residual drugs in CTX-UPLNPs was much higher than that in cabazitaxel solution after the same time.The experimental results showed that CTX-UPLNPs could load and protect cabazitaxel,and improve the stability of cabazitaxel in the gastrointestinal environment.The competitive inhibition of ASBT by UDCA could reduce the uptake of CTX-UPLNPs by cells,and the uptake of CTX-UPLNPs by cells was higher than that of CTX-PLNPs.The results showed that CTX-UPLNPs modified by UDCA could target ASBT and increase the uptake of cabazitaxel by intestinal epithelial cells through ASBT-mediated transport.The UDCA-modified polymer-lipid hybrid nanoparticles designed and prepared in this study could improve the solubility,gastrointestinal stability and intestinal epithelial cell uptake of cabazitaxel,which was expected to provide the possibility for further study on how to improve the oral bioavailability of cabazitaxel. |
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