Investigative Ophthalmology and Visual Science. 2006;47:222-225.
According to this study, after 4-6 weeks of Xalatan use:
"Ninety-four percent of the bottles had concentrations within 90% to 110% of the labeled amount. No difference in latanoprost concentrations was found between the bottles used for 4 weeks versus those used for 6 weeks.
"CONCLUSIONS. In an eye clinic setting, latanoprost ophthalmic solution 0.005% remains stable after 4 or 6 weeks of patient use from the same bottle when stored at room temperature."
Although we've known this for some time, this is another study that enables us to confidently advise patients they don't need to store Xalatan in the refrigerator. Now I'd like to know what happens to Xalatan when it is left in a hot car in the middle of summer in Arizona.