Figure 4. The percentage of lutein remaining on the mucous membrane after a steady flow of normal saline solution (NSS) at 5 min (orange bar) and 60 min (green bar; *One way ANOVA followed by Tukey’s post hoc test, p-value <0.05). For all formulations, lutein retained on the membrane was >50% after 5 min and >40% after 60 min under fluid flow, respectively. Error bars show the standard deviation (n=3).