Abstract
Purpose :
Perfluorohexyloctane (PFHO, NOV03) is under clinical investigation for the treatment of dry eye disease (DED) associated with meibomian gland dysfunction. We evaluated the physical properties of PFHO along with its in vitro effect on meibum from a human volunteer.
Methods :
PFHO structure and interactions with standard lipid esters (LEs), a wax ester (WE), and with meibum from a 68-year old Caucasian volunteer without DED were studied using absorbance spectroscopies. Lipid composition and concentrations in the collected meibum were measured using nuclear magnetic resonance (NMR) spectroscopy. Evaporation rates were measured gravimetrically.
Results :
PFHO is a liquid between -30°C and 70°C and evaporates at a rate of 0.137 ± 0.003 µm/min. When layered on top of physiological saline, PFHO inhibited the evaporation rate of saline by 84% (P < 0.0001). Stearylpalmitate and cholesterylstearate, two ordered LEs, were visibly insoluble in PFHO, whereas oleyloleate, a fluid WE, was soluble in PFHO. Addition of PFHO had a minimal effect on ordered LEs but increased the fluidity of the WE by 64%. Addition of PFHO to meibum (19:1, g:g) significantly increased the magnitude of the phase transition and decreased the cooperativity and minimum frequency of the phase transition of meibum but did not change the order of the lipids at physiological temperatures.
Conclusions :
PFHO is a potential replacement for the tear film lipid layer in patients with DED: it significantly decreases the rate of evaporation, a property related to tear film stability. However, PFHO did not change the lipid order in meibum from a healthy volunteer. We speculate that PFHO could form a protective layer on the tear film surface that enhances tear film spreading as well as decreasing the rate of evaporation. Further in vitro rheological and in vivo evaporation rate studies are warranted along with interaction studies with meibum from DED patients.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.