A decrease of the rabbit's physiologic IOP after the application of specific amino acids and double combination of...

To compare the effect of amino acids mixtures to a double combination of antiglaucomatics on the physiologic intraocular pressure (IOP) in rabbits.

Experimental evaluations were performed on 5 female rabbits of the New Zealand White species.

1) After instillation of 10 % L-arginine. HCl in the double combination of antiglaucomatics: a) 0.5 % Timolol with 0.005 % Xalatan mixture, the biphasic IOP decrease was measured. The mean decrease in 24 hours was - 2.9 torr; b) 2 % Trusopt with 0.005 % Xalatane mixture in 24 hours, the biphasic decrease of the IOP was measured. The mean decrease in 24 hours was - 4.2 torr; c) Fixed combination COSOPT the mean IOP value decrease was - 1.8 torr. 2) The IOP decrease achieved during 24 hours by instillation of the amino acid 10 % L-taurine.HCl and the double combination of antiglaucomatics: 0.5% Timolol with 0.005% Xalatane mixture was in average - 2.8 torr. The pupilar diameter was not changed.

We assume that after the interaction of the selected amino acids 10 % L-arginin or 10 % L-taurin with the double combination of antiglaucomatics (Trusopt and Xalatan, COSOPT or Timoptol and Xalatan) a new substance was formed. The effect of this substance is not separate or additive but acts as a newly formed substance. In vivo, it is only a weak interaction with the free amino acids of the conjunctival sac and the antiglaucomatics. The amino acids interacted in vitro with the double combination of antiglaucomatics resulting in a new "bio-antiglaucomatic" better penetrating into the target area. This new substance was responsible for a more significant decrease and regulation IOP after the mixture application compared to the antiglaucomatics alone (Fig. 1, Ref. 23).