Glycyrrhetinic Acid-modified Chitosan Nanoparticles For Liver Targeting Drug Delivery: Construction And Evaluation

Glycyrrhiza uralensis is the dry root and rhizome of leguminous plant Glycyrrhiza uralensis Fisch,Glycyrrhiza in flata Bat,Glycyrrhiza glabra L.The herb is sweet and mild with the effect of strengthening spleen,expectorant and relieving cough,reduce the pain,reconcile the various herbs.Glycyrrhizic acid and glycyrrhetinic acid are the main active component of glycyrrhiza uralensis.Both of them are pentacyclic triterpenoids.It is speculated that the cell membrane of rat's liver contained specific high binding sites for glycyrrhetinic acid and glycyrrhizin,liposome or serum albumin modified with glycyrrhetinic acid/glycyrrhizin,expressed a considerably high affinity to hepatocytes,glycyrrhetinic acid and glycyrrhizin can be used as the targeting group for liver.Kehoe celery Osthole aka methoxy phenol(Osthole,Ost),as Furanocoumarins,widely present in Umbelliferae plants,such as Cnidium,Angelica,Angelica,etc.Modern Pharmacological Research shows that Osthole can inhibit the secretion of hepatitis B surface antigen,reversing Caspase3 mediated hepatocyte apoptosis,reducing enzyme activity of liver,can significantly improve the degree of fatty liver degeneration,prevent and protect alcoholic fatty liver of rats.In this paper,glycyrrhetinic acid are used as liver targeting group chitosan(Chitosan,CTS)with excellent biological properties as the carrier material,formed a novel hepatic drug delivery system using glycyrrhetinic acid-modified chitosan as the carrier,to deliver Osthole into liver.eventually prepared a kind of drug loaded nanoparticles by ionic gelation method targeting the liver.And the physicochemical properties,encapsulation efficiency,drug loading,particle size and morphology of the nanoparticles were characterized by studies of pharmacodynamic and in vivo and in vitro experiment of liver targeting,which expected to receive a novel of liver targeting agents.We synthesized glycyrrhetinic acid-modified chitosan carrier(GA-suc-CTS)via hemisuccinate as a bridged group.In vector Enoxolone degree of substitution index,filter out the optimal synthesis process,and the compound are characterized by UPLC-MS chromatography,high performance liquid chromatography,infrared spectroscopy,nuclear magnetic resonance spectroscopy,elemental analysis and other methods and techniques the products were detected verification feature group,the results indicate that the target compounds synthesized successfully.After the successful synthesis of the novel carrier,sodium tripolyphosphate used as cross-linking agent,Ost/GA-suc-CTS nanoparticles were formed by ionic gelation methold.By particle size analyzer for particle size and dispersion coefficient of nanoparticles,combined with transmission electron microscopy morphology of nanoparticles measured screened optimal preparation,The resultant Ost/GA-suc-CTS nanoparticles exhibited spherical in shape and a size range of 155 nm.Ost/GA-suc-CTS nanoparticles with a maximal encapsulation efficiency of 95%and the drug-loading ratio of 40%,and have a good dispersion,present a more rounded rules spherical.Dynamic dialysis method was used to detect in vitro release of the Ost in the Ost/GA-suc-CTS nanoparticles,the results showed a burst release within the initial 2 h,followed by sustained release but at different rate in 12 h,and the final amount released was about 99%of the total Ost.The in vitro drug release of the Ost/GA-suc-CTS NPs was consistent with the Higuchi equation,suggesting that the mechanism of Ost released from the carriers was a slow release process.By ultra performance liquid chromatography tandem mass spectrometry(UPLC/MS/MS),conducted in mice pharmacokinetics and tissue distribution studies,pharmacokinetic results showed that the AUC and Cmax of the Ost/GA-suc-CTS NPs group had significant differences compared to Ost group,showed that Ost/GA-suc-CTS NPs can significantly improve the bioavailability of the osthol.Liver tissue distribution results showed that the content of Ost in mouse liver of the Ost/GA-suc-CTS NPs was much higher than osthol group,which expressed a considerably high affinity to hepatocytes.Description the Ost/GA-suc-CTS NPs were able to significantly improve the bio availability of osthol,and has a better liver targeting effection.A comparative study by the Methyl tetrazolium(MTT)assay was conducted.HepG2 cell were cultured with Osthol,Ost/CTS NPs,Ost/GA-suc-CTS NPs,and each group were cultured 24h,48h and 72h,respectively.The results of growth inhibition and inhibition of half the concentration of HepG2 cell showed that growth inhibition rates of glycyrrhetinic acid-modified chitosan nanoparticles at 24,48 h and 72h on HepG2 cell were 36.46%,43.57%,44.57%,respectively.At 48h the inhibition rate of glycyrrhetinic acid-modified chitosan nanoparticles was significantly higher than Osthole group,The inhibitory effect of the NPs was dose and time-dependent.;The IC50 of glycyrrhetinic acid-modified chitosan nanoparticles in 24h,48h and 72h were 41.58,25.63,24.32 ?g · mL-1,respectively.In 48h glycyrrhetinic acid-modified chitosan nanoparticles was significantly lower than the Osthole group.A comparative study of the Osthol,chitosan nanoparticles containing the drug,glycyrrhetinic acid-modified chitosan nanoparticles for drug-induced improvement of carbon tetrachloride in mice with acute liver injury.The results showed that glycyrrhetinic acid-modified chitosan nanoparticles were able to significantly inhibit the MDA content in acute liver injury induced by CCl4,liver index,spleen index increased,ALT and AST activity in liver and the reducing activity of SOD effectively,suppressed that Ost/GA-suc-CTS NPs can reduce the injury degree of liver tissue in mice,protect acute liver injury in mice.