| Corneal neovascularization(CNV)is one of the main causes of severe visual impairment.The formation of CNV can impair visual sensitivity and even lead to vision loss.Based on statistics,over 1.5 million cases of corneal blindness are annually reported worldwide.As an organ of the human visual system,eyes have many special physiological barriers and clearance mechanisms.These barriers result in short retention time of drugs,poor penetration of the intraocular tissues,and extremely low bioavailability after the administration of the traditional eye drops.which bring many limitations to drug therapies.In order to solve these above problems,this study constructs multifunctional active targeting nanocarriers through pharmaceutical preparation technology to achieve the efficacy enhancement and the toxicity reduction of corneal neovascularization therapy.Chitosan oligosaccharide(CSO)and hydrophobic quercetin(QRT)nanomicelles were prepared by linking the hydrophilic block chitosan oligosaccharide(CSO)with the hydrophobic block quercetin(QRT)via the succinic anhydride connecting arm.The chitosan oligosaccharide and quercetin nanomicelles were further functionalized by glycylsarcosine(GS)dipeptide to construct esterase-sensitive double-targeted selfassembly polymer nanomicelles(GSCQ).The model drug Nintedanib(NTB)was loaded into nanomicelles by the thin film dispersion method,and the drug-loaded micelles GSCQ@NTB were constructed for the treatment of corneal neovascularization disease model.The successful preparation of nanocarriers was proved by a series of these characterizations.Transmission electron microscopy(TEM)showed that the nanomicelles were uniformly spherical.The particle size of the drug-loaded nanomicelles was about 191nm and the Zeta potential was about+3mV.The loading capacity of the carrier system of this drug was about 8.1%and the encapsulation rate was about 89.0%.In addition,the drug release characteristics were dependent on the degradation of micelles by esterase.In the presence or absence of esterase,the cumulative drug release amount within 12 hours were respectively 81.1%and 46.8%.Human corneal epithelial cells(HCECs)were selected to evaluate the biological functions of GSCQ@NTB in vitro.Cytocompatibility and uptake experiments showed that the nanomicelles could be effectively ingested by human corneal epithelial cells with no corresponding cytotoxicity observed.Western blot assay was used to verify the inhibition of P-gp expression induced by NTB.The inhibition of neovascularization in vitro was certified by the scratch test on human umbilical vein endothelial cells(HUVECs)and chick embryo chorioallantoic membrane model.With the utilization of New Zealand white rabbits as experimental subjects,it was observed that nanomicelles eye drops with the fluorescence labeling can remain in the cornea for more than 8 hours after administration shown by fluorescence labeling.Meanwhile,the drug retention was much higher than that of free drug form.Furthermore,the corneal neovascularization model was constructed by alkali burn method.Additionally,the anti-neovascularization effect of GSCQ@NTB nanomicelles on the disease model was characterized by corneal confocal scanning and optical coherence tomography.As a result,slit lamp vascular observation and fluorescence quantitative PCR results show that GSCQ@NTB has a more significant inhibitory effect on corneal pathological neovascularization than the free drug and dexamethasone treatment group do,which is attributed to the pharmacokinetic characteristics of nanomicelles after topical administration and effect on ocular surface transport protein.In conclusion,GSCQ@NTB nanomicelles system with good biocompatibility has been prepared in this study to achieve high bioavailability of drugs in cornea in the form of micellar eye drops.It has good therapeutic effects and effectively avoids the potential shortcomings of traditional eye drops,providing good application prospects for noninvasive treatment of corneal neovascularization. |
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