Purpose

Essential fatty acids (EFAs) as dietary supplements are used in treating dry-eye for reducing inflammation at the ocular surface. Their topical application in eye drops to deliver fatty acid (FA) directly to the ocular surface requires thorough investigation. Being lipids in nature EFAs can interact with tear lipids and affect tear stability. This study aimed at investigating the biophysical interactions of EFAs with Meibomian lipids.

Methods

Rheology of mixtures of Human Meibomian lipids with EFAs (LA-linoleic acid, ALA-alpha-linolenic acid), OA (oleic acid), and GLA (gamma-linolenic acid) was studied using Langmuir trough technology on an artificial tear solution at the ocular surface temperature. Pressure-area profiles were used to determine compressibility and elasticity of the mixed films.

Results

LA enhanced spreading of Meibomian lipids and increased their compressibility and elasticity which can be beneficial for tear stability. ALA condensed Meibomian lipids film with less elasticity deemed unfavourable for tear stability. OA expanded Meibomian lipids but decreased elasticity at high compressions making films less stable. GLA had little or no favourable effect on tear stability. Higher concentrations of FAs made films less stable.

Conclusions

EFAs or OA in topical ophthalmic preparations can affect spread and stability of the tear film lipid layer. Rheology of mixed films should be tested using Langmuir trough technology to determine suitable type and amount of a lipid additive for therapeutic eye drops. In topical applications, the omega-6 LA (not omega-3 FA) at low concentrations (20 mol%) can be beneficial for enhancing tear stability in dry eye patients.

中文翻译：

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评估必需脂肪酸在干眼局部用眼科制剂中的使用。

目的

必需脂肪酸（EFA）作为膳食补充剂用于治疗干眼症，以减轻眼表炎症。它们在滴眼液中的局部应用将脂肪酸（FA）直接递送到眼表需要彻底的研究。作为自然界中的脂质EFA可以与泪液脂质相互作用并影响泪液稳定性。这项研究旨在调查全民教育与睑板脂质的生物物理相互作用。

方法

使用Langmuir槽技术在人工泪液中，研究了人类睑板脂质与EFA（LA-亚油酸，ALA-α-亚麻酸），OA（油酸）和GLA（γ-亚麻酸）的混合物的流变学。眼表温度。压力-面积曲线用于确定混合膜的可压缩性和弹性。

结果

LA增强了睑板脂质的扩散，并增加了其可压缩性和弹性，这有利于泪液稳定性。ALA浓缩的睑板脂膜具有较低的弹性，被认为不利于泪液稳定性。OA扩展了睑板脂质，但在高压缩下弹性降低，使薄膜稳定性降低。GLA对泪液稳定性几乎没有或没有有利影响。FA浓度越高，薄膜的稳定性越差。

结论

局部眼科制剂中的EFA或OA会影响泪膜脂质层的扩散和稳定性。应使用Langmuir槽技术测试混合膜的流变性，以确定用于治疗性眼药水的脂质添加剂的合适类型和量。在局部应用中，低浓度（20 mol％）的omega-6 LA（非omega-3 FA）可有助于增强干眼患者的泪液稳定性。