PURPOSE: To evaluate the effect of instilled amino acid L-arginine.HCl and combination of two antiglaucomatics (Trusopt with Xalatane mixture) on the physiological intraocular pressure IOP in rabbits. METHODS: Into the left conjunctival sac of 5 female rabbits of the New Zealand White species was instilled the mixture of 2% Trusopt (Dorsolamidi hydrochlorici) with 0.005% Xalatane (Latano-prostum) and after the one week break, the 10% L-arginine.HCl in 2% Trusopt with 0.005% Xalatane mixture. The IOPs were measured in 0, 5, 15, 30, 60, 120, 180, 240 min. and 24 hours after the instillation. The right eyes were used as controls. RESULTS: 1. The combination of two antiglaucomatics in comparison with the control eye decreased significantly the IOP value already after 15 min. The major decrease of the IOP (6.5 mm Hg) was observed after 240 min. After 24 hours, the effectiveness was not significant. 2. After instillation of the 10% L-arginine.HCl in 2% Trusopt with 0.005% Xalatane mixture, during the next 24 hours, the biphasic decrease of the IOP was established. The maximum of the effectiveness of this mixture is after 30 min (decrease by 5.1 mm Hg). The evidence of the effect was present also after 24 hour (decrease by 2.5 mm Hg). The mean value of the IOP of the control eyes in both groups of experiments in course of 24 hours was stable and was at the initial values. CONCLUSIONS: The combination of two antiglaucomatics (Trusopt with Xalatane mixture) was used. The effect of those two substances is not separate or additive but acts as a newly formed substance. In the structures of the eye, this new substance has only poor interaction with the free amino acids of the conjunctival sac in vivo. After in vitro interaction of the L-arginine.HCl and combination of two antiglaucomatics (Trusopt with Xalatane mixture), a new bioactive substance with stronger effect on physiologic IOP values was produced.

Klinika oftalmológie LF UK Bratislava SR