[Comparison of the permeability between the rabbit cornea and sclera ex vivo]

Objective: Comparison of the permeability between the rabbit cornea and sclera ex vivo by determining the concentration of gatifloxacin using LC-MS/MS method, which may provide the basis for a new route of drug administration. Methods: Experimental study. The permeability of the cornea and sclera in healthy male New Zealand rabbits was evaluated by using Franz diffusion pool. We chose both gatifloxacin ophthalmic solution and gel as the test drugs, and calculated the cumulative permeation amounts (Qn), apparent permeability coefficient(P(app)). Results: The linear range of gatifloxacin was 5-1 000 ng/ml. The intra-day and inter-day precision was 1.7% -2.8% and 1.0% - 2.3%. Q(n) and P(app) of gatifloxacin ophthalmic solution in cornea and sclera ex vivo were 177.57, 517.52 μg/cm(2) and 4.34, 12.51 cm/s respectively, whereas that of gatifloxacin ophthalmic gel were 151.87, 411.05 μg/cm(2) and 3.66, 9.21 cm/s. Conclusion: This validated method could be applied to determine the gatifloxacin. The cumulative permeation amounts and apparent permeability coefficient of sclera are significantly higher than that of cornea for both ophthalmic solution and gel, suggesting that the development of a new route of drug administration based on sclera may have potential advantage. (Chin J Ophthalmol, 2019, 55: 928-932).