Possibility of Topical Antioxidant Treatment of Cataracts: Corneal Penetration of Pyruvate in Humans

Aim: It was our aim to study the penetration of sodium pyruvate into the aqueous humor of humans after its topical application as an eye drop. Methods: Two hours prior to surgery, one drop of 5% sodium pyruvate prepared in artificial tears was instilled in the eye to be operated upon for cataract extraction. The drops were given 4 times at 10-min intervals. Eye drops containing tropicamide, phenylephrine, flurbiprofen and tobramycin were also given preoperatively. At the start of surgery, an aqueous sample was withdrawn, kept refrigerated and analyzed for pyruvate within 2 h. The cataracts were then extracted either by routine extracapsular extraction or by phacoemulsification, both followed by intraocular lens implantation. The pyruvate level was determined colorimetrically by reacting it with 2,4-dinitrophenyl hydrazine. Results: The level of pyruvate in the aqueous sample of patients that did not receive pyruvate eye drops was only 0.145 +/- 0.06 m M. In the group given pyruvate, it increased to approximately 0.35-0.525 m M. Conclusion: The results demonstrate that topical administration of pyruvate is effective in elevating its concentration in the aqueous humor to a level adequate to offer protection against oxidative stress to the lens and other intraocular tissues. Hence, it should be feasible to carry out clinical trials with this compound aimed at treating diseases such as cataracts and diabetic retinopathy induced by generation of reactive oxygen species and consequent oxidative stress. Copyright (C) 2008 S. Karger AG, Basel