Study On Pharmacokinetics And Tissue Distribution Of Angiopep-2 Modified Naringin Nanoparticles

With an aging population,the number of people suffering from brain diseases such as Alzheimer’s disease is increasing every year.However,the blood-brain barrier,formed by the interaction of cerebral microvascular endothelial cells with pericytes,glial cells and basement membranes in the neurovascular unit,prevents 100%of large molecule drugs and over 98%of small molecule drug candidates from entering the cerebrospinal fluid and brain tissue,greatly reducing the effectiveness of drugs in the treatment of brain diseases.Animal experiments have shown that the flavonoid naringin has ameliorating effects in Parkinson’s disease and Alzheimer’s disease;In vitro experiments have shown that naringin can promote the proliferation of Aβ_25-35 induced damaged PC12 cells.The low permeability of the blood-brain barrier has resulted in very low bioavailability of naringin,limiting its potential role in improving brain diseases such as Alzheimer’s disease.In this experiment,we developed a novel drug delivery system across the blood-brain barrier by combining naringin with nanoparticles followed by receptor-targeted modification and used to investigate the pharmacokinetics and in vivo tissue distribution of the particles after tail vein injection in rats.The main study of this paper was divided into three parts as follows.1.Preparation and characterization of Angiopep-2 modified naringin nanoparticlesThe naringin-loaded nanoparticles（PEG-PCL-NP）were prepared by the emulsification solvent evaporation method and characterized with the particle size of94.10±3.72 nm,the zeta potential of-3.34±0.69 m V,the encapsulation efficiency and drug loading of 78.79±0.43%and 25.89±0.29%respectively.The naringin-loaded targeting nanoparticles（ANG-PEG-PCL-NP）were prepared by covalent binding of maleimide to sulfhydryl groups and modified with Angiopep-2 on the surface of PEG-PCL-NP,which were also characterized with a particle size of 126.85±5.82 nm,a zeta potential of-2.85±0.24 m V,and a drug loading and encapsulation rate of 25.08±0.43%and 72.95±0.72%respectively.Both nanoparticles had uniform morphology and distribution,and both had obvious sustained-release effects,which could increase the release time of naringin and improve the bioavailability.2.Pharmacokinetics of Angiopep-2 modified naringin nanoparticlesAfter tail vein injection of free naringin solution,PEG-PCL-NP and ANG-PEG-PCL-NP（calculated as naringin content of 15 mg/kg）in rats,respectively,0.5 m L of blood was collected from the orbital venous plexus before（0 h）and 0.083、0.5、1、2、4、8、12 and 24 h after administration,and the samples were processed and analyzed by UPLC-MS/MS for the content of naringin in the three nanoparticles,and the main pharmacokinetic parameters were calculated by Winnonlin 8.1 software.The results showed that the area under the curve AUC0-∞of ANG-PEG-PCL-NP was significantly higher than that of PEG-PCL-NP and free naringin solution by 1.4 and 2.1 times（p<0.05）,the half-life t1/2（4.18±0.49 h）was higher than that of PEG-PCL-NP group（3.85±1.25h）and free naringin group（3.18±1.26 h）,the mean residence time MRT was 1.22and1.72 times higher than that of PEG-PCL-NP and free naringin solutions,respectively（p<0.05）,and the clearance rate CL was lower than that of the other two groups by 1.3and 2.3 times（p<0.05）.This indicates that ANG-PEG-PCL-NP has a significantly different pharmacokinetic profile from PEG-PCL-NP and free naringin solution,prolonging the circulation time of naringin in vivo.3.A study of the tissue distribution of Angiopep-2 modified naringin nanoparticlesAfter the rats were administered free naringin solution,PEG-PCL-NP and ANG-PEG-PCL-NP by tail vein injection for 1h（calculated as naringin content of 15 mg/kg）respectively,the rats were anesthetized with sodium pentobarbital and perfused with heart,and the brain,heart,liver,spleen,lung,kidney,stomach,uterus and ovary tissues were rapidly removed,and the naringin content in the tissue samples was analyzed by UPLC-MS/MS analysis.The results showed that after the tail vein injection of three drugs,naringin was the highest in liver tissue.The PEG-PCL-NP group（10.27±0.56μg/g）and the free naringin solution group（3.61±0.16μg/g）had the lowest content of naringin in brain tissue.After administration,the naringin content in the brain tissue of the ANG-PEG-PCL-NP group（14.26±0.99μg/g）was significantly higher than that in the other two groups（p<0.05）.This shows that the ANG-PEG-PCL-NP,a nanoparticle delivery system targeted at the nanoparticle,has strong cross-blood-brain barrier capability.In this study,a naringin nanoparticle delivery system with Angiopep-2 as the target receptor was synthesized and its in vivo pharmacokinetics and tissue distribution were comparatively studied.The results showed that the half-life of ANG-PEG-PCL-NP in rats increased,the clearance rate decreased,and the brain content increased significantly compared to free naringin.We hope to provide relevant theoretical knowledge and basic data for clinical trials on drug entry into the brain.