·To prepare the cell-penetrating peptide Penetratin-modified liposome (Pen-Lip) for ophthalmic application and evaluate its applicability to treat fundus neovascularization diseases through topical instillation.

·The copolymer DSPE-PEG₂₀₀₀-Pen was synthesized by the addition reaction of DSPE-PEG₂₀₀₀-Mal and Penetratin, and Pen-Lip was then prepared by the thin film dispersion method. The cellular uptake experiment was used to determine the optimal ratio of Penetratin to modify liposomes. The average particle size, Zeta potential and polydispersity index (PDI) of Pen-Lip were characterized by the nano particle size potentiometer, and the morphology of Pen-Lip was observed by using transmission electron microscope (TEM). The encapsulation efficiency and the drug loading of Pen-Lip with conbercept were determined by centrifugation. Pen-lip was incubated in the PBS or the PBS containing 50% fetal bovine serum for 48 h and the stability of Pen-Lip was investigated by the change of particle size and the morphology under TEM. The CCK-8 assay was conducted to detect the cytotoxicity of Pen-Lip to human corneal epithelial cell (HCEC) and human retinal pigment epithelium (ARPE-19), and the uptake of Pen-Lip by ARPE-19 was observed by using laser confocal microscope. The diffusion cell device was used to detect the permeability of Pen-Lip through the isolated rabbit cornea, and the apparent permeability coefficient (P_app) was calculated. The toxicity of Pen-Lip with conbercept to the corneal tissue was evaluated by the hydration value.

·The optimal ratio of Penetratin to modify liposomes was 3%. The average particle size of Pen-Lip was (148.07±3.51) nm, the Zeta potential was (5.66±0.91) mV, and the PDI was 0.227±0.045. TEM results showed that Pen-Lip had a smooth spherical structure. The encapsulation efficiency of Pen-Lip was (44.06±3.70) %, and the drug loading was (2.84±0.24) %. The particle size of Pen-Lip did not change significantly and TEM showed uniform dispersion after dispersing in the PBS or the PBS containing 50% fetal bovine serum for 48 h, exhibiting the good stability of Pen-Lip. When Pen-Lip was at the concentration of 15?500 μg/mL, Pen-Lip had no cytotoxicity to HCEC and ARPE-19. Compared with unmodified liposomes, ARPE-19 cells had significantly higher uptake of Pen-Lip (P=0.000). In the experiment of rabbit cornea penetration in vitro, the P_app of Pen-Lip was significantly higher than that of unmodified liposomes (P=0.000). There was no statistically significant difference in the hydration value of the rabbit cornea treated with drug-loaded Pen-Lip compared to the untreatd group (P>0.05).

·Pen-Lip has good stability, biocompatibility and corneal permeability in vitro and can be taken up by retinal cells, which is a potential ocular drug delivery system to treat fundus neovascularization diseases through topical instillation.