Cultured rabbit corneal epithelium elicits levofloxacin absorption and secretion

Evidence for carrier-mediated transport of levofloxacin in the isolated rab bit cornea has been found. However, it is not known whether this mechanism is located in the epithelium or the endothelium. To resolve this question, we have measured the kinetics of levofloxacin uptake in primary cultures of rabbit corneal epithelial cells. The results indicate that levofloxacin accumulation was time dependent and a steady state was reached after 30 min. Maximal uptake occurred from a sol ution whose pH was 6.5. The uptake process was stereoselective and concentr ation dependent. In addition to the uptake, secretion of levofloxacin also occurred. These results indicate that the corneal epithelium is the site of levofloxa cin transport mechanisms, mediating both absorption and secretion.