Pharmacokinetics of pirfenidone after topical administration in rabbit eye

Pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone) is a new, broad-spectrum agent that has an inhibition effect on the proliferation, migration, and collagen contraction of human Tenon's fibroblasts, and thus modulating the wound healing process of glaucoma filtering surgical site. This study investigated the pharmacokinetics of topically administered pirfenidone (0.5%) in rabbit eyes.

Pirfenidone solution (50 μl) was instilled into the rabbit's conjunctival sac. The rabbits were quickly sacrificed at 2, 5, 8, 10, 15, 20, 30, 60, 90, and 120 min after the administration and ocular tissues were obtained. The concentrations of pirfenidone in conjunctiva, sclera, cornea, aqueous humor, and vitreous were determined by high performance liquid chromatography.

After topical administration, there was wide distribution and fast clearance of pirfenidone among the various ocular tissues. The mean maximum concentrations (C(max)) of pirfenidone in cornea, conjunctiva, sclera, aqueous humor, and vitreous were 9.64 mg/g, 9.62 mg/g, 2.13 mg/g, 34.88 mg/l and 0.52 mg/l, respectively. The half-life for these tissues was 18.26, 34.16, 15.71, 70.91, and 39.48 min, respectively.

Measurable concentrations of pirfenidone are achieved in ocular tissues after topical application in rabbit model. Topical administration of pirfenidone may be an effective approach for modulation of wound healing responses in glaucoma filtration surgical site.