Surface chemistry of the interactions of cationic nanoemulsions with human meibum films

PurposeIkervis® (IKV) cationic nanoemulsions (CNE) were demonstrated to enhance tear film stability in vivo possibly via effect on tear film lipid layer (TFLL). Therefore the interactions of IKV and of binary and ternary mixtures of its constituents were studied with human meibum (MGS) films. The binary mixtures consisted of 2% mid chain triglycerides (MCT) blended with 0.005% cetalkonium chloride (CKC) and 0.3% Tyloxapol (e.g. MCT/CKC and MCT/Tylo respectively). The ternary mixture contained MCT/CKC/Tylo (2%/0.005%/0.3%). The impact of 0.1 μM bovine submaxillary mucin (BSM) on CNE/MGS interactions was also evaluated.MethodsMGS and CNE oils were spread at the air/water interface of a Langmuir surface balance in range of 2D ratios (20/1, 10/1, 5/1, 3/1, 2/1 and 1/1) at two measurement regimes: with (i) MGS or (ii) total lipid amount kept constant. The films capability to reorganize during dynamic area cycling was evaluated. The layers dilatational rheology was probed via the step/relaxation method. Films structure was monitored with Brewster Angle microscopy.ResultsThe binary mixtures showed limited spreading and miscibility with MGS resulting in poor mechanical properties. The ternary mixture and IKV spread and mixed well with MGS. At fixed MGS amount, the inclusion of CNEs enhanced the structure, properties and elasticity of the layers. At fixed total lipid, the films remained primarily elastic, but at high (≤3/1) CNE content the elasticity slightly decreased and heterogeneities in layers structure were observed. BSM enhanced the ternary mixture (IKV)/ MGS interactions.ConclusionsAt physiologically relevant MGS/CNE ratios MCT/CKC/Tylo and IKV interact favorably with MGS films. The positive effect of BSM suggests that polyanionic polysaccharides can enhance CNE/TFLL interactions in vivo.Support: Collaborative study grant by Santen SAS, Evry, France.