How lamellar liquid crystal emulsion can strengthen skin barrier ?

How to define lamellar liquid crystal

The lamellar liquid crystal emulsion is a new type of emulsion which is different from the traditional emulsion system. It is the ordered arrangement of surfactant and oil molecules formed at the oil-water interface. This ordered arrangement makes the emulsion of lamellar liquid crystal structure showing better application performances than conventional emulsion systems in terms of stability, controlled release and moisturizing.

At Seppic, we offer MONTANOV^TM emulsifiers range promoting the formation of lamellar liquid crystals in emulsions. Indeed, some emulsifiers can create lamellar phases, by structuring the aqueous phase, and arranging themselves in bilayered around the oil droplets. They can form a liquid crystalline phase, or a gel phase.

How to formulate lamellar liquid crystal emulsion?

Let’s take the case study with our MONTANOV™ range.

MONTANOV™ can be added in the heated oily phase (or can be added to the water phase if the oil % is low). Add the oil phase to the heated water phase, and emulsify with a homogenizer (rotor stator). Cold gradually and gently to 50°C, to allow the formation of lamellar liquid crystals. Finish the cooling with gentle to moderate stirring and add stressful ingredients at the end of the process.

Discover our formulation video with MONTANOV™ L:

How can you be sure that your emulsion contains lamellar liquid crystals?

Two different types of lamellar liquid crystals can be visible under microscopy: those around the oil droplets and those in the continuous aqueous phase.

• The liquid crystals around the oil droplets are in the form of several lamellar bilayers. The latter forms a barrier against coalescence ¹. These liquid crystals are anisotropic and therefore are visible in the form of Maltese crosses under an optical microscope with polarized light.
• Liquid crystals also exist in the continuous aqueous phase in the form of lamellar phases ^{2, 3, 4}. These networks are viscoelastic and more or less consistent, which prevent the creaming phenomenon. Unlike liquid crystals formed around oil droplets, the lamellar phases in the aqueous phase are not visible under the optical microscope, but can be identified using an electron microscope or by means of rheological analysis. Indeed, these lamellar phases increase the elasticity of the emulsion.

What are the benefits of lamellar liquid crystal in formulation?

General expected benefits of lamellar liquid crystal

In theory, the lamellar liquid crystal structure should result in a few advantages than the conventional emulsion in cosmetics applications, for example, improved stability, controlled-release and good skin sensory feeling.

Proven benefits of lamellar liquid crystal with our MONTANOV^TM

Extensive stability studies mimicking extreme conditions have been conducted on MONTANOV^TM 202 emulsions. The aim was to understand the influence of time, temperature, transport and formulation composition on the creation and the stability of lamellar phases and lamellar bilayers. 

Multiple formulations have been made to see the impact of the emulsifier nature (Seppic’s and other emulsifiers), the impact of polymers and the impact of the oil phase composition on those structures. Emulsions have then been submitted for up to 6 months to various temperatures (up to 45°C) and to a specific machine mimicking the impact of transportation. A standardized protocol allowed to evaluate the presence or the absence of microscopically visible lamellar liquid crystals in the various formulations regularly during those 6 months.

As a result, and contrary to other tested emulsifiers, MONTANOV^TM demonstrated great capacity to create stable lamellar liquid crystals over time, over temperature and through transportation

What are the benefits of lamellar liquid crystal emulsions on skin barrier?

By studying lamellar liquid crystal formulations, we realised that their organisation was similar to that of the skin. We can speak of a biomimetic texture.

It can be defined as a texture that mimics the ingenuity of the skin and takes its inspiration from the substances or functions that our skin produces naturally. These similarities between the texture and the skin optimise the penetration of ingredients into the stratum corneum for better results.

MONTANOV™ emulsions respect the structure of the skin. This is due to their lipids, which insert between the existing lipids of the stratum corneum. The skin's organization is therefore not disrupted, but reinforced!

The MONTANOV™ range is more than just emulsifiers for the formula, it also provides sought-after benefits to the skin:

• Strengthen the skin barrier: MONTANOV™ 202 and MONTANOV™ L were tested in vitro for the reinforcement of the skin barrier. They showed a decrease in transepidermal water loss, compared to the reference . Therefore, the tested MONTANOV™, strengthen the skin barrier function and limit skin dehydration. 
• Moisturize: MONTANOV™ 202, MONTANOV™ L and MONTANOV™ 82 were tested in vivo. They showed a better moisturizing effect than the reference. Thus, the MONTANOV™ range has an immediate effect on skin hydration and also acts as a water reservoir, five hours after application. The increased hydration provided by MONTANOV™ is the evidence of an efficient skin barrier

• Restructure: Analysis of skin structure with MONTANOV™ 202 showed a decrease in skin roughness after 30 minutes. The diminution of this factor shows that the emulsifier has a significant restructuring effect. MONTANOV™ 202 is a suitable ingredient to visibly smooth skin’s texture.
• Activity enhancing properties: MONTANOV™ L was tested as a booster of efficacy for two active ingredients.
  • In order to seek a longer moisturizing effect, MONTANOV™ L was tested in combination with AQUAXYL™. The study showed that together they can significantly boost the moisturizing effect for up to 48 hours.

Hope you like to discover the structure and benefits of lamellar liquid crystal emulsions and that you’ll be able now to check by your own if you obtain some in formulation. Get inspired by our formulas booklet to create your biomimetic textures!

Discover our formulas with MONTANOV™

Sources

¹Tadros ThF., Dimitrova GT, Luckham P., Ftaelman MC. And Loll P. Euro Cosmetics 3, 17 (1995)

² Barry B.W. “Viscoelastic properties of concentrated emulsifiers. Advance in Colloid and Interface Science”, 5, 37-75 (1975)

³ Barry B.W. and Elleston G.M. “Influence of gel networks in controlling consistency of O/W emulsifiers stabilized by mixed emulsifiers”, Journal of Texture, 4, 53-81 (1973)

⁴ Eccleston G.M. “Functions of mixed emulsifiers and emulsifying waxes in dermatological lotions and creams”, Colloid Surface A, 123-124, 169-182 (1997)