Pharmacokinetics of polyvalent proteinase inhibitor (aprotinin) in eye tissues

Drugs having as their active substance aprotinin (trasylol, gordox, etc.) are widely indicated in the treatment of eye pathologies having as their basis an enhanced proteolytic enzyme activation. Our studies have exposed a decrease in proteolytic activity in both eye tissues and tear fluid in response to Gordox administration. Up to date there are no works concerning pharmacokinetics of aprotinin in the eye tissues. The aim of this work was to study the pharmacokinetics of 125I-aprotinin in rabbit eye tissues after instillation. A presence of the substance was registered in the cornea, aqueous humor, and ciliary body within a period of 10-90 minutes after administration, but not in other tissues. Calculation of the pharmacokinetic parameters of aprotinin penetration in the eye showed that its mean residence time in the cornea, aqueous humor and ciliary body was 50-60 min. The addition of polyvinyl alcohol to the instillation solution increased the level of the substance in the tissues, but did not change its mean residence time. The medicine should be instilled every 1-1.5 hrs to support high and stable levels of aprotinin in the eye.