Evaluation Of Triamcinolone Acetonide Plgananoparticles Cross-Ocular Barrier Properties And Pharmacokinetics And Pharmacodynamics

Local eye drop administration is the most common non-invasive treatment of eye diseases.It is widely used in clinical treatment due to its good compliance and high safety.However,due to the special structure of the eye and the role of the physiological barrier in the posterior segment of the eye,it is difficult for the drug to penetrate the intraocular barrier during the treatment of posterior ocular diseases with eye drops,and the therapeutic effect is poor.Although the effective treatment concentration can be achieved by the invasive method of administration,the invasive method of administration such as implantation,vitreous injection,etc.has many problems such as poor patient compliance and postoperative complications,which limits its wide clinical application.Based on this,this article uses degradable polylactic acid-glycolic acid copolymer（PLGA）as a drug carrier to prepare a local eye drop drug delivery system for PLGA nanoparticles modified with cell penetrating peptides（CPPs）.Properties,intraocular distribution,in vitro release,elimination behavior in the eye,pharmacokinetics,and pharmacodynamics are evaluated for intraocular adaptability and feasibility.1.Using the fat-soluble fluorescent dye Coumarin-6（Coumarin 6,C6）as a probe,PLGA nanoparticles were prepared by emulsification solvent volatilization method,and surface modification was performed with materials with different characteristics,and the particle size and potential were analyzed.The results showed that The results showed that PLGA-NPs,dihydroxypropyl-βcyclodextrin（2-HP-βCD）modified nanoparticles（2-HP-βCD）-PLGA NPs,cell penetrating peptide modified nanoparticles CPPs-（2-HP-βCD）-PLGA NPs have an average particle size in the range of 70-85 nm;the Zeta potentials are-（9.74±0.61）m V,-（8.98±0.89）m V and-（5.75±1.71）m V,respectively.The polydispersity coefficient（PDI）is less than 0.2.Differential scanning calorimetry and X-ray diffraction measurement results show that there is a force between C6 and the PLGA carrier,suggesting that a new phase is produced.The in vitro release behavior of nanoparticles with different surface characteristics was studied.Among them,（2-HP-βCD）-PLGA NPs,CPPs-（2-HP-βCD）-PLGA NPs and cyclodextrin aqueous suspensions have the same release model,all of which are erodible Ritger-Peppas release models;PLGA-NPs are Higuchi release models,which means that the addition of cyclodextrin changes the release behavior of nanoparticles.At the same time,judging from the cumulative release percentage,the final release of each experimental group is below20%,indicating that C6 is tightly bound to the carrier and is not easy to leak;the release of cyclodextrin aqueous suspension is between PLGA NPs and（2-HP-βCD）-PLGA NPs show that the release behavior is the joint effect of cyclodextrin and nanoparticles.The encapsulation rates of PLGA-NPs,（2-HP-βCD）-PLGA NPs,and CPPs-（2-HP-βCD）-PLGA NPs are 49.79±0.011%,68.20±0.068%,76.60±0.11%,respectively;The addition of cyclodextrin and cell-penetrating peptide improved the encapsulation efficiency of the nanosystem.From the perspective of fluorescence leakage rate,the fluorescence leakage rate of different prescriptions within 6 hours is less than 6%,which can better contain the fluorescent substance,which lays the foundation for tracking nanoparticles in the body.2.To evaluate the intraocular distribution characteristics of nanoparticles,the fluorescent probe tracing method was used.From the distribution of the whole eye,administered by eye drop,PLGA-NPs,（2-HP-βCD）-PLGA NPs,and CPPs-（2-HP-βCD）-PLGA NPs are distributed on the retina.There are two distribution mechanisms of nanoparticles in the eyeball:one is to form retention in the anterior segment of the eye represented by the cornea due to its adhesion characteristics,and the other is to enter the posterior segment of the eye via the conjunctival-scleral pathway.From the perspective of cell safety,the three nanoparticles with different surface properties at a C6concentration of 0.010-0.40μg/m L all have a higher cell survival rate,and the blank carrier concentration of 0.013-1.00 mg/m L has a higher cell survival rate.In terms of cellular uptake,the nanoparticles modified by the transmembrane peptide reached the maximum uptake within 0.5 h,and the addition of the transmembrane peptide accelerated the cell’s uptake of the nanoparticles.The uptake mechanism of the transmembrane peptide modified nanoparticles is studied.The cell uptake process is an energy-dependent active transport process,and its fast uptake characteristics are related to its uptake process consisting of multiple pathways.The above experiments described the intraocular distribution,safety,cellular uptake and mechanism of PLGA nano-delivery carriers with different surface modifications using C6 as a fluorescent probe.The above experiment described the intraocular distribution,safety,cellular uptake and mechanism of PLGA nano-delivery vehicles with different surface modifications using C6 as a fluorescent probe.Among them,the cellular uptake speed and intake volume of CPPs-（2-HP-βCD）-PLGA NPs than the others,may be used as a suitable carrier with lipophilic drug triamcinolone acetonide（triamcinolone acetonide,TA）for delivery segment of the eye.3.Using CPPs-（2-HP-βCD）-PLGA NPs as the carrier,the particle size of the system containing triamcinolone acetonide is 73.43±1.45 nm,the Zeta value is-3.87±0.58,and the polydispersity coefficient is 0.205±0.0014.From the in vitro release test,the release behavior of TA aqueous suspension is Higuchi model,and the release behavior of CPPs-（2-HP-βCD）-PLGA NPs is the erosion Ritger-Peppas model,indicating that TA release behavior has changed.From the corneal permeability test in vitro,the cumulative permeability of CPPs-（2-HP-βCD）-PLGA NPs was 4.63±0.29μg,which was 1.92 times that of TA water suspension group.The steady-state slope of the transmembrane peptide modified nanoparticles is 1.10 times that of TA water suspension.The apparent permeability coefficient(P_app)and steady-state flow rate(J_ss)of the CPPs-（2-HP-βCD）-PLGA NPs group were 1.15 times and 1.13 times that of the TA water suspension group,respectively.The preparation of TA as CPPs-（2-HP-βCD）-PLGA NPs increases the permeability of the drug at the cornea.4.The results of tear elimination research showed that prolonged the retention time of the drug and increased the retention volume.The C_max of CPPs-（2-HP-βCD）-PLGA NPs is 3.53 times that of TA suspension.The AUC_0→180min of CPPs-（2-HP-βCD）-PLGA NPs is 3.41 times that of TA suspension.The pharmacokinetic test results of aqueous humor showed that the C_max of CPPs-（2-HP-βCD）-PLGA NPs was 11.38 times that of TA water suspension,the AUC_0→360min was 4.85 times that of TA water suspension,and the average retention time MRT（h）is 1.73 times that of TA water suspension,which can effectively increase the concentration of TA in aqueous humor.5.To evaluate the pharmacodynamics of CPPs-（2-HP-βCD）-PLGA NPs,a mouse model of oxygen-induced retinopathy was established.Observed from the HE-stained sections,in the CPPs-（2-HP-βCD）-PLGA NPs treatment group,the arrangement of the interstitial cells was close to that of the normal group,and the interstitial cells that broke through showed a sporadic distribution.From the statistical results of the number of nuclei that broke through the inner membrane of the retina,the nanoparticles modified by the penetrating peptide could significantly reduce the number of nuclei that broke through the inner membrane of the retina（P<0.05）.The full text discusses the physical and chemical properties of penetrating peptide nanoparticles,in vitro release and in vitro corneal permeability of rabbit eyes,cell uptake,tear elimination kinetics,aqueous humor pharmacokinetics and pharmacodynamics.The results show that CPPs-（2-HP-βCD）-PLGA NPs improve the bioavailability of drugs in aqueous humor mainly by increasing the transmembrane uptake capacity of nanoparticles and increasing their permeability.The CPPs-（2-HP-βCD）-PLGA NPs carrier has the ability to deliver drugs to the target site and make the drugs play a therapeutic effect,laying the foundation for further research on non-invasive drug delivery across the eye barrier nanoformulations.