Whole-Eye Perfusion Model for Screening of the Ocular Formulations via Confocal Laser Scanning Microscopy
Various physiological, anatomical barriers make ocular drug delivery very challenging. Hence, better in vitro screening models are needed for rapid screening of the formulations. In this study, a simple whole-eye perfusion model was designed and its application was explored for screening targeted formulation across the full-thickness cornea using confocal laser scanning microscopy. PEG-cholecalciferol-based integrin targeted coumarin-6 micelles (TC6M) and non-targeted coumarin-6 micelles (NTC6M) were developed by solvent diffusion evaporation technique. The formulations NTC6M and TC6M had particles size 23.5 ± 5 nm and 28.5 ± 6 nm respectively and osmolality of 294–300 mOsml/Kg. The whole-eye perfusion model was developed using porcine eye. TC6M and NTC6M were instilled on the excised porcine eyes as well as in the eyes of NZW rabbits. Corneas were excised from the experimental eyes; coumarin-6 penetration across the corneas was analyzed using confocal microscope. Coumarin-6-loaded micelles had particle size below 50 nm. NTC6M formulations showed penetration to the deeper layers up to 500 μm porcine eyes and up to 50 μm in rabbit corneas. However, TC6M formulations exhibited superior retention, as higher fluorescent intensities were observed in upper layers up to 50 μm depth in the porcine eye and 20 μm depth in rabbit eye. Hence, applicability of whole-eye perfusion model in preliminary screening of the formulations was successfully demonstrated. Whole-eye perfusion model when combined with confocal microscopy has potential to be used as an efficient tool for rapid screening and optimization of various ophthalmic formulations.
KEY WORDSperfusion model micelles confocal ocular coumarin-6
We thank Dr. Imran Vohra for his technical guidance. We are also thankful to Dr. Dmitry for providing access to the Confocal Laser Scanning Microscope in Maglab (FSU) and Mr. Howell (owner of Jhonston’s meat market Monticello, Fl) for providing porcine eyes.
This project is supported by NSF-CREST Center for Complex Materials Design for Multidimensional Additive Processing (CoManD) award # 1735968 and Research Center in Minority Institute (RCMI) U54, 2454MD007582-34A1 grant
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- 5.Villani E, Galimberti D, Viola F, Mapelli C, Mojana F, Pirondini C, et al. The cornea in Sjögren’s syndrome: an in vivo confocal study. Invest Ophthalmol Vis Sci. 2006;47(13):1365.Google Scholar
- 17.Kutlehria S, Behl G, Patel K, Doddapaneni R, Vhora I, Chowdhury N, et al. Cholecalciferol-PEG conjugate based nanomicelles of doxorubicin for treatment of triple-negative breast cancer. AAPS PharmSciTech. 2017.Google Scholar
- 19.Dang S, Lu X, Zhou J, Bai L. Effects of 1alpha, 25-dihydroxyvitamin D3 on the acute immune rejection and corneal neovascularization in high-risk penetrating keratoplasty in rats. Acad J First Med Coll PLA. 2004;24(8):892–6 903.Google Scholar
- 39.Varga M. Textbook of rabbit medicine. Elsevier Health Sciences; 2013.Google Scholar