Abstract
Purpose:
To examine and compare the intraocular pressure (IOP) lowering effect and conjunctival irritation (hyperemia, chemosis and conjunctival discharge) of four different topical valsartan formulations (1.0%, 2.0% 3.0% and 4.0%) in healthy rabbits
Methods:
All experiments were conducted in accordance with the Association of Research in Vision and Ophthalmology’s (ARVO) Statement for the Use of Animals in Ophthalmic and Vision Research. The research was approved by an internal ethics committee for animal experimentation. Twelve healthy New Zealand White rabbits were treated with either, valsartan 1.0%, valsartan 2.0%, valsartan 3.0% or valsartan 4.0% (3 animals/group). One dose of study article was administered to both eyes of each animal every 12 hours for 5 days. IOP was assessed on days 2 and 5 using a Goldman tonometer and conjunctival irritation was assessed using a slit-lamp biomicroscope to evaluate hyperemia, chemosis and conjunctival discharge.
Results:
The IOP mean decrease on the second day was 2.1mmHg, 2.3mmHg, 1.8mmHg and 2mmHg for the valsartan 1.0%, 2.0% 3.0% and 4.0% respectively; on the fifth day the decrease compared to baseline was 2.1mmHg, 2.5mmHg, 2mmHg and 2.6mmHg respectively. Comparing the percentage reduction of baseline versus final IOP, no statistical differences were found in the inter-group comparisons. No chemosis or conjunctival discharge were found in any study group. There was no statistical difference between groups for the conjunctival hyperemia.
Conclusions:
The four formulations of valsartan have lowering pressure properties; despite the higher 4.0% drug concentration, valsartan 4.0% does not increase the conjunctival irritation. Further studies would be needed to determine the long term effect on IOP and safety of valsartan formulations.
Keywords: 568 intraocular pressure