Purpose: To evaluate influence of mixture of the 2 amino acids (L-arginine.HCL and L-lysi-ne.2HCL.H2O) in the antiglaucomatic – β-blocker Timoptol – on the physiologic intraocular pressure (IOP) in rabbits (experiment). Methods: The mixture of 10% L-lysine.2HCL.H2O + 10% L-arginine.HCL in 0, 5% Timoptol was instilled into the left conjunctival sac of the 5 adult rabbit’s (female of the New Zealand White species) and the right eye was used as control. The IOP and pupilar diameter were measured before and in 5th, 15yth, 30th, 60th, 120th, 180th and 240th min. and 24 hours after the instillation. Results: The experimental results proved that the non-selective β-blocker Timoptol interacts at the same time with two amino acids. The mixture of 10% L-lysine.2HCL.H2O + 10% L-arginine.HCL in 0, 5% Timoptol decreased the physiologic IOP in two phases. The first phase started from application up to 15th min. In this period parallel IOP decrease occurred also in control eye (with no significant difference). The second phase started in 30th min. after the instillation and lasted until the end of experiment. In this phase the control eye IOP remained linear after the initial over the baseline increase. The eye with instilled mixture showed significant IOP decrease (p < 0.01). Maximum difference between the two IOP’s was measured in the 180th (7, 3 mmHg; 35.4%). From this moment IOP slightly increased up to the 24th hour showing still significantly lower level- 5,0 mmHg (24.3%) compared with the control (p < 0.01). Conclusions: Results proved that in the mixture of 10% L-lysine.2HCL.H2O + 10% L-argi-nine.HCL in 0,5% Timoptol a new substance, the „specific bioantiglaucomatic“ is created by interaction. Compared with the substances alone, mixture of the 2 amino acids in the antiglaucomatic decreased the physiologic intraocular pressure (IOP) in rabbits (experiment) with high significance for 24 hours.

        Key words: influence of mixture of the 2 amino acids in Timoptol on the rabbits IOP, specific antiglaucomatic