Cytotoxicity evaluation of a novel latanoporst 0.005% nanoemulsion

Abstract

AbstractPurposeTo evaluate the cytotoxicity of a new Latanoprost Benzalkonium chloride (BAK)‐free nanoemulsion and to compare it with a Latanoprost solution containing BAK.MethodsNormal Human Conjunctival epithelial cells (IOBA‐NHC) were incubated for 15, 30, and 60 minutes with 1:6 dilutions of either latanoprost solution containing BAK (LSc), (latanoprost 0.005%, BAK 0.02%, Xalatan, Pfizer) or latanoprost nanoemulsion (LNe), (latanoprost 0.005%, potassium sorbate 0.18%; Louten Emulsion, POEN). Cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V‐FITC and propidium iodide.ResultsCytotoxicity evaluation: the values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to control group, whereas values obtained from cells exposed to LSc were around 30% relative to control group at all study times (p < 0.05 at 15 and 30 minutes; p < 0.01 at 60 minutes).Cell death evaluation: the percentage of viability was significantly lower in cells exposed to LSc compared with those incubated with LNe at all study times (p < 0.05 at 15 and 30 minutes; p < 0.01 at 60 minutes). Viability of cells exposed to LNe was higher than 90% at all study times, whereas there was a time‐dependent decrease in cells exposed to Lsc. The percentage of viable cells in the LNe group was comparable to the viability of control group (93.1%) at all study times. No statistical differences between groups reached in early apoptotic cells. A significant increase of late apoptosis and necrosis cells were observed at all study times for those incubated with Lsc (p < 0.05; p < 0.01 at 30 and 60 minutes).ConclusionsThe new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. It suggests that the new formulation could be gentler on the eye surface than currently available BAK preserved latanoprost solutions, with levels of cytotoxicity equivalent to control.