How is hydrolyzed hyaluronic acid encapsulated in certain skincare products?

The hyaluronic acid is a polysaccharide naturally present in the extracellular matrix of connective tissues. Essential for skin hydration, it plays a significant role in the processes of healing and cell regeneration. Due to its interesting skin properties, the hyaluronic acid is included in the composition of many cosmetic products, in various forms. Obtained by hydrolysis of high molecular weight hyaluronic acid (raw form), hydrolyzed hyaluronic acid is composed of relatively small fragments. It is often encapsulated in a matrix before being integrated into a cosmetic product, in order to improve its stability, bioavailability, and effectiveness.

In cosmetics, hydrolyzed hyaluronic acid is typically encapsulated in liposomes. These are spherical vesicles made up of phospholipid bilayers, similar to human cell membranes. The hydrophilic part of the liposomes, with which hyaluronic acid has an affinity, is oriented inward and protects the active ingredient from enzymatic degradation. Liposomes also enhance the penetration ability of hyaluronic acid due to their capacity to merge with cell membranes. Sometimes, hyaluronic acid is encapsulated in niosomes, which are analogs of liposomes produced from non-ionic surfactants, but this is less common. The encapsulation in liposomes is done in the following way:

• Liposome formation.

  There are various methods to form liposomes from lipids, such as reverse phase evaporation, injection, electroformation, microfluidics, thin layer hydration, freeze-drying of double emulsions, membrane extrusion... These techniques all involve four fundamental steps: drying a mixture of lipids from an organic solvent, dispersing the lipids in an aqueous medium, separating and purifying the formed liposomes, and analyzing the final product.

• Preparation of liposomal hyaluronic acid gel.

  The encapsulation of hyaluronic acid into liposomes is a relatively straightforward process. The active ingredient is first dissolved in a buffer solution with a pH of 7.4 before being added to the liposome suspension. The mixture is then homogenized by vortexing for a few minutes. The liposomes in which the hyaluronic acid has been encapsulated are then stored at 4°C, a temperature that allows them to remain stable.

• Integration into a cosmetic formulation.

  The encapsulated hyaluronic acid is then incorporated into a cosmetic product such as a cream, serum, or lotion. The goal is to create a homogeneous formulation that gradually releases the hyaluronic acid in a hydrolyzed form, thereby maximizing its benefits for the skin and reducing the risk of irritation.