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E. Bodek, K. Sonmez, Z. Wang, H. J. Kaplan, T. H. Tezel; Facilitated Intraocular Drug Delivery Using DOTA-TAT Multifunctional Carrier Core. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5809.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the efficacy of DOTA (tetraazacyclo-dodecanetetra-acetic acid)-TAT carrier core for intraocular delivery of macromolecules.
A multifunctional microcyclic carrier core consisted of two cell-penetrating TAT peptides (L22) and fluorescein molecule (FITC) was constructed on a DOTA scaffold. 100 and 10 µg of the DOTA-L22-FITC construct was injected intraperitoneally to 12 adult C57BL/6 mice. 3 hours later blood was removed by whole-body saline perfusion and animals were perfused with 4% paraformaldehyde. FITC penetration into retina, brain, kidney and liver was determined with a spectrophotometer (490/520 nm). Injections of L22-FITC, DOTA-L22 and FITC alone were taken as controls. A similar construct of DOTA-L22-FITC-Ethacrynic acid was injected into the subtenon’s space of 6 C57BL/6 mice and tissue penetration was determined with fluorescence microscopy. In another set of experiments, subtenon injections of DOTA-L22-FITC-Bevacizumab (Avastin) construct was used to ablate laser-induced CNV in 6 C57BL/6 mice and 3 Dutch Belted Rabbits. For this purpose, Bruch’s membrane was rupture with a dfNdYAG laser (532 nm; 14-40 spots/1000 mW/0.1"). Ten days after laser photocoagulation DOTA-L22-FITC-Bevacizumab construct carrying Bevacizumab (116 µg for mice; 330-990 µg for rabbits) was injected into the superior subtenon’s space. Subtenon injections of same amounts of Bevacizumab, PBS, DOTA-L22-FITC were taken as controls. Four days after the injection eyes were enucleated and choroidal neovascularization yield over the laser spots was determined under a fluorescein microscope.
DOTA-L22 construct increased the retinal penetration of FITC 8.3 ± 0.7 times. Increasing the amount of injected DOTA-L22-FITC from 10 to 100 µg did not increase the tissue penetration proportionally (2.9 ± 0.5 times), indicating a possible rate-limitation and/or saturation across blood-retinal barrier at higher doses. Two hours after subtenon injection of DOTA-L22-FITC-Ethacrynic acid diffused into the retina as patchy columns. Subtenon injection of DOTA-L22-FITC-Bevacizumab significantly reduced the incidence of laser-induced CNV both in mice (70.4 vs. 38.9) and rabbits (41.2% vs. 25.7%).
DOTA-TAT microcyclic carrier core significantly enhances intraocular penetrance of multiple drugs. It carries the advantages of small size, targeted intracellular drug delivery and non-invasive monitoring of therapeutic agents. Intraocular delivery of anti-VEGF agents can be one of its immediate applications.
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