Purchase this article with an account.
Georgi Asenov Georgiev, Norihiko Yokoi, Slavyana Ivanova, Vesselin Tonchev, Philippe Daull; Surface chemistry of the interactions of cationic nanoemulsions with human meibum films. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6188.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
As cationic nanoemulsions (CNE) are showing promise, as eyedrops and ophthalmic drug (e.g. cyclosporine) delivery vehicles, it is important to know their interplay with the tear film lipid layer. Therefore the interactions of three CNE (Cationorm, Ikervis and Ikervis Vehicle) were studied with human meibum (MGS) films. Both Cationorm and Ikervis formulations contain cetalkonium chloride (CAC) as 0.2 wt% or 0.24-0.25 wt% of their oil phase respectively.
MGS were collected from 4 healthy volunteers (25-36 [30.75±5.12 SD] years old) and then dissolved in chloroform to a unified 1 mg MGS/ml stock solution. MGS and CNE were spread at the air/phosphate buffered saline interface of a Langmuir surface balance to ensure range of MGS/CNE oil phase 2D ratios: 100/1, 50/1, 20/1, 10/1, 5/1, 3/1, 2/1 and 1/1. The films capability to reorganize during dynamic area changes were evaluated through the surface pressure-area compression/expansion isocycles. The layers dilatational rheological properties were probed via the step/relaxation method through Fourier analysis (in the 1-10-5 Hz range) and by exponential decay modeling of the relaxation transients. Films structure was monitored with Brewster Angle microscopy. All the samples were evaluated at 25 and 35°C.
At high (≥ 50/1) MGS/oil phase ratios the inclusion of CNE had no noticeable effects on the film properties. In the range of 20/1-2/1 MGS/Ikervis formulations and 20/1-3/1 MGS/Cationorm oil phase ratios the layers showed improved spreading, higher maximum surface pressures and increased film thickness compared to pure MGS. The contribution of the elastic modulus to the film dilatational viscoelasticity also increased. At 1/1 MGS/Ikervis and ≤2/1 MGS/Cationorm oil phase the layers remained primarily elastic, but the contribution of long (≥ 500 s) viscous relaxation process started to increase and slight heterogeneities in the MGS/Cationorm layers were observed.
Under physiologically relevant high MGS/oil phase ratios CNEs interact favorably with MGS films and enhance their structure and surface properties. Only at low MGS/oil phase ratios slight perturbations are observed in the layers structure and viscoelasticity. The latter can be related with the increased amount of water soluble surfactant compounds in the film subphase at high CNE concentrations, which however might be rapidly diluted by the aqueous turnover in vivo.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only