The effect of Benzalkonium chloride on the intraocular pressure lowering efficacy of a local ROCK‐inhibitor (AMA0076)

Abstract Purpose To elucidate the effect of Benzalkonium chloride (BAK) on the intraocular pressure (IOP) lowering efficacy of a local ROCK‐inhibitor AMA0076 (Amakem NV) in the rabbit eye. Methods Topical administration of AMA0076 (0.1%, 0.3% and 0.5%) was tested in a normotensive New Zealand White rabbit model (5 rabbits/group). The IOP lowering efficacy of the compound was determined with or without the addition of 0.01% BAK. The contralateral eye was used as a control and was treated with vehicle (H2O PEG) in all groups. IOP was measured at baseline and at 1, 2, 3, 4, 5, 6, 7 and 8h post administration. Data at individual time points were analyzed using mixed model analysis for repeated measures. P < 0.05 was considered to be statistically significant. Results Single topical administration of AMA0076 significantly lowered IOP in a concentration dependent manner compared to the control eye (p<0.05). Placebo/vehicle administration did not induce significant changes in IOP. The maximal IOP lowering effect of AMA0076 0.1%, 0.3% and 0.5% containing 0.01% BAK was 38%, 45% and 53%, which was significantly stronger compared to their BAK‐free equivalents: 21%, 28% and 37% (p=0.005, p=<0.001; p=0.008 respectively). Conclusion The local ROCK inhibitor, AMA0076 was significantly more effective in lowering IOP in the presence of 0.01% BAK.