Alcaftadine trial used this concentration of drug:

* ALCAFTADINE is a H1 receptor antagonist, and can be used for allergic conjunctivitis* The trial done for alcaftadine used 0.25% solution.* The trial states: "When Alcaftadine was tested against placebo and olopatadine, only Alcaftadine 0.25% was shown to have a clinically significant reduction in conjunctival redness scores 7 and 15 minutes after administration'