The intraocular dynamics of vancomycin hydrochloride ophthalmic ointment (TN-011) in rabbits

The intraocular dynamics of 1% vancomycin hydrochloride (VCM) ophthalmic ointment (TN-011) in rabbits was investigated. The animals used in the study were 42 pigmented rabbits with normal eyes (normal group) and 17 pigmented rabbits with Bacillus subtilis-infected eyes (BS group). The infection in the BS group was induced by a method previously established by the authors. Fifty milligrams of a 1% VCM ophthalmic ointment was administered into the cul-de-sacs of the animals' eyes unilaterally in both groups. Serum, bulbar conjunctiva (only from the normal group), cornea, iris-ciliary body, and vitreous were collected 15, 30, 60, 120, and 240 min after the drug administration as samples. Drug concentration was measured by the bioassay method. In the normal group, VCM in the bulbar conjunctiva reached a maximum concentration (98.98 +/- 46.48 microg/g) at 30 min, and decreased to a level below the detection limit at 240 min. The maximum concentration of VCM in the cornea (12.04 +/- 4.73 microg/g) was observed at 30 min. VCM was not detected in the aqueous humour, iris-ciliary body, vitreous, or serum in the normal group at any point. In the BS group, the maximum concentration of VCM was 25.60 +/- 11.01 microg/g in the cornea 15 min after drug administration, and 5.18 +/- 2.60 microg/ml in the aqueous humour at 30 min. VCM in the aqueous humor could be detected (0.37 +/- 0.19 microg/ml) even after 240 min. VCM was not detected in the iris-ciliary body, vitreous, or serum at any point. The intraocular dynamics of 1% VCM ophthalmic ointment (TN-011) revealed that VCM reached the estimated effective concentrations in the aqueous humour as well as extraocular tissues of Bacillus subtilis-infected rabbit eyes.