The Study On Nanostructured Lipid Carrier-Intraocular Lens Based Sustained Release System Of Soybean Active Ingredient Of Genistein

Posterior capsule opacification(PCO)is one of the most common complications after cataract surgery.The traditional ocular implants suffer from fast drug metabolism and possible tissue damages.Based on the characteristic of PCO formation,we develop a novel drug delivery system by jointing nanostructured lipid carrier incorporating genistein,an active component from soybean,onto the intraocular lens surface,and implant this device into the eye during PCO surgery.This drug delivery system can enhance the drug concentration in the humor for a longer duration time than the traditional approaches,and the PCO prevention effect can be prolonged for several weeks after IOL implantation.The extraction process of genistein from soybean was firstly evaluated.Based on the results of single factor investigation,an orthogonal experiment method was applied to optimize the factors affecting the extraction amount of geinistein from soybean:alcohol solution concentration,alcohol solution volume(ratio of weight of soybean powder to volume of alcohol solution),temperature,extraction time.The optimized extraction process condition is as follows:alcohol solution concentration 60%,W/V ratio 1:5,temperature 60?,extraction time 2 hours.The optimized extraction process was repeated twice for a higher extraction amount of genistein The apparent t solubility and oil-water partition coefficient in different solvent was also investigated.The results showed that genistein was poorly water soluble and have a better solubility in Miglyol 812 than other oil solvent.Stability results show that genistein has slight degradation in aqueous solution.The formulated GEN-NLC showed round appearance and uniform size distributionThe Genistein incorporated nanostructured lipid carrier(GEN-NLC)was developed using melt-emulsification method,by using Glyceryl Behenate and Miglyol 812 as the oil phase,and soybean lecithin and Cremphor EL as the emulsifiers.Based on the results of single factor investigation,a central composite design plus response surface method was applied to optimize the formulation of GEN-NLC.The effects of genistein concentration,liquid lipid concentration,and Cremphor EL concentration on the particle size,particle distribution,zeta potential and encapsulation efficiency(EE)were investigated and the morphology of GEN-NLC,the crystallinity of genistein in NLC,and stabilisty were also evaluated.The results showed that the optimized formulation of GEN-NLC is as follows:Genistein 14mg;Compritol 888 ATO 210mg;Miglyol 812N 90mg;soy lecithin 88mg;Cremphor EL265mg.The average particle size was 72.16 nm,distribution coefficient is 0.20,zeta potential of 7.19 mv,the EE of 91.20.Drugs are amorphous in lipids.Stability test results show that the GEN-NLC was stable for around 72 hours in 25?.In order to obtain a longer stability,a freeze-drying process was investigated for GEN-NLC,and the concentrations of freeze-drying protective agents were also evaluated.In vitro release results show that the release of GEN-NLC is 72 hours,with a bi-phase release characteristic.The human lens epithelial cell(HLEC)line was used for the cellular study of GEN-NLC.CCK-8 cytotoxicity experiments showed that the blank NLC was non-toxic to lens epithelial cells,and 50?g/mL of GEN-NLC is appropriate for cell growth inhibition.The fluorescent Rhodamine B was incorporated into NLC to mimic the cellular behavior of GEN-NLC.The results showed that the NLC can be effectively absorbed by lens epithelial cells,mainly by clathrin-mediated endocytosis.Apoptosis tests showed that the reason for the growth inhibition of HLEC by GEN-NLC is the induced apoptosis.In order to extend the residence time of GEN-NLC in the eye,we joint the GEN-NLC to the surface of the implanted intraocular lenses(IOL).Different amount of sodium deoxycholic acid(SDC)and chitosan hydrochloride decorate(CHC)were used to modify the GEN-NLC to make it carry different amount charges.The SDC or CHC modified NLCs were attached to the IOL surfaces by absorbing and bonding methods.The Rayner 570C hydrophilic acrylate IOL bonding SDC of 40 mg can obtain largest drug loading of 67.61 ?g.The In vitro release results show that GEN-NLC-IOL of 570C can release drug for about 72 hours.When implanted into the eyes of rabbits,the drug concentration in humor was determined.Results showed that the area under the curve(AUC)and average residence time(the MRT)of GEN-NLC-IOL group were significantly higher than the group of anterior chamber injection of GEN-NLC,showing a 11.53-fold and 6.77-fold increase,respectively.The retention time of drug(T1/2)was extended for 3.79-folds at 14.746 hours.The elimination rate in aqueous humor(Ke)of GEN-NLC-IOL group was 7.4%of the anterior chamber injection group.The pharmacodynamics tests showed that the GEN-NLC-IOL can effectively inhibit the accumulation of HLEC and the formation of PCO.The ultrastructure observation of rabbits results show that there is no significant effect to the other tissues in eyes.Based on the results above,the GEN-NLC-IOL drug delivery method can prolong the retention of drug in the eye and prevent the PCO formation when implanted into the eye during cataract surgery.