Preparation And Evaluation Of Tripterine-loaded Broccoli Lipid Nanoparticles

Objective: Tripterine,a triterpenoid isolated from Thunder God Vine root,has a variety of pharmacology activities,such as anti-inflammation,anti-oxidation and anti-cancer effects.However,poor aqueous solubility of tripterine limits its intestinal absorption,resulting in low oral bioavailability.This thesis aims to prepare tripterine-loaded lipid nanoparticles(LNs)using broccoli-derived lipids for enhancement of oral bioavailability of tripterine.Methods: 1.1-octanol was used to extract the liposoluble components of broccoli.The solvent-diffusion technique was used to prepare tripterine-loaded broccoli lipid nanoparticles(Tri-BLNs).As a control,tripterine-loaded common lipid nanoparticles(Tri-CLNs)were prepared using Precirol ATO-5(glycerol distearates).2.The particle sizes of Tri-BLNs and Tri-CLNs were measured using Zetasizer Nano ZS.The entrapment efficiency and drug loading were determined by centrifugal filtration method.The morphology of Tri-BLNs was probed using transmission electron microscope(TEM).The drug release profiles of Tri-BLNs and Tri-CLNs were assessed in deionized water with 1% SDS as solubilizing agent.Lypolysis of Tri-BLNs and Tri-CLNs were investigated in the fasted-state simulated intestinal fluid(Fa SSIF)supplemented with porcine pancreatic lipase.3.The cellular uptake of Tri-BLNs,Tri-CLNs and pure drug were evaluated using MDCK-II cells.To explore the trafficking mechanism of Tri-BLNs,the cellular uptake experiments were performed in the presence of endocytosis inhibitors.Coumarin-6 loaded Tri-BLNs and TriCLNs were prepared and examined by confocal laser scanning microscopy for investigation of intracellular distribution.Rat in situ single-pass intestinal perfusion was performed to determine the effective permeability coefficients(Peff)of Tri-BLNs,Tri-CLNs and pure drug.4.SD rats were orally administered with each of Tri-BLNs,Tri-CLNs or tripterine suspensions,and intravenously administered with pure drug(dissolved in a cosolvent of propanediolethanol-water).The plasma drug concentrations at different time points were quantified byUPLC-QTOF/MS.Win Nonlin 4.0 software was used to calculate the pharmacokinetic parameters and relative bioavailabilities of Tri-BLNs and Tri-CLNs.Results: 1.The apparent solubility of tripterine reached 4 mg/m L after being formulated into Tri-BLNs.The particle sizes of Tri-BLNs and Tri-CLNs were 75.6 nm and 151 nm,respectively.The entrapment efficiency values of Tri-BLNs and Tri-CLNs were 99.9% and 79.5%,respectively.The drug loading values of Tri-BLNs and Tri-CLNs were 18.9% and 18.2%,respectively.TriBLNs were spherical in morphology with uniform size.Tripterine in Tri-BLNs was in an amorphous state.After 24 h,the accumulative release percentages for Tri-BLNs and Tri-CLNs were less than 2%.As compared with Tri-CLNs,Tri-BLNs showed a lower rate of lipolysis and greater anti-enzymatic hydrolysis ability.2.The uptake rates of tripterine through Tri-BLNs,Tri-CLNs and pure drug were 15.1%,10.7% and 7.88%,respectively.Clathrin-mediated endocytosis was mainly responsible for the cellular uptake of Tri-BLNs.As compared with Tri-CLNs,Tri-BLNs showed stronger fluorescence intensity and intracellular distribution.The Peff values of Tri-BLNs at different intestine segments were significantly higher than those respective values of Tri-CLNs and pure drug.3.The Cmax values of Tri-BLNs and Tri-CLNs were increased by 4.44 and 2.31 times compared with tripterine suspensions.The relative bioavailabilities of Tri-BLNs and Tri-CLN were 494% and 282%,respectively.Both types of LNs could improve the oral absorption of tripterine,and the degree of improvement for Tri-BLNs was much higher than that for Tri-CLNs.Conclusion: We originally prepared Tri-BLNs using broccoli-derived lipids,which significantly enhanced the oral bioavailability of tripterine by improving its solubility and permeability,thereby providing a novel carrier for improving the oral absorption of poorly water-soluble drugs.