Stability and protection: why actives are encapsulated

In brief

Many skincare actives start to break down as soon as they meet oxygen, light, a shifting pH or water. Encapsulation holds the active inside a shell, apart from those stresses, so it stays intact for longer in the bottle. A sealed pack protects the formula as a whole; the shell protects the active within it. Both are part of the approach described on the Technology hub.

Four things that break an active down

Oxygen. Dissolved oxygen in a water-based serum, and the air that enters a bottle each time it is opened, oxidizes susceptible molecules. Oxidation often shows as a color shift toward yellow or brown. The best-known example is L-ascorbic acid, the pure form of vitamin C.

Light. Ultraviolet and visible light carry enough energy to break chemical bonds in some actives. Retinoids are the classic light-sensitive group, which is why they are sold in opaque or tinted packs.

pH. Each active has a pH range in which it is stable. Outside it, some actives change form or lose activity, and some interact with other ingredients that need a different pH. Formulators often have to choose between the ideal pH for one active and the ideal pH for another.

Water and time. In an aqueous base, slow reactions such as hydrolysis continue for the whole shelf life. Coenzymes such as NAD are among the actives formulators handle with care in water. Heat during transport and storage speeds all of these reactions up.

Antioxidants, chelating agents, opaque packs and airless pumps are the conventional defenses. Each addresses the formula or the container. None changes the fact that the active sits directly in the base.

What the shell adds

NanoVeil is Vegalab's multi-layer nano-encapsulation platform. NanoVeil builds a multi-layer biopolymer shell around an active, up to 20 programmable layers, so the active is held stable until defined conditions release it. Actives that oxidize or degrade quickly in an open formula stay intact for longer inside the shell.

The shell works as a physical buffer between the active and the base. Oxygen, pH and other reactive ingredients reach the shell before they reach the active. Because the layer design is programmable, it can be set to suit the particular active. The step-by-step mechanism is on How encapsulation works, and the way this approach compares with liposomes and other carriers is on Carrier systems compared.

Encapsulation also separates actives from each other. Two ingredients that would react in an open base can sit in the same formula when one of them is held in a shell.

The pack does the rest

A shell protects the active. The container protects everything else, and the two work together.

The sealed vial format is the strongest example in the range. The vials and stoppers are sterilized before filling, each vial is sealed under a re-enterable stopper and an aluminum crimp, and the serum is a preserved cosmetic formulation. Because the dose is drawn through the stopper, the contents are not opened to room air between uses. After the first draw, the vial is refrigerated and used within 28 days. See the Hyaluronic Skin Repair sealed vial set for the format in practice, and Preservation and format for how the pack and the preservative system work together.

The 30 ml bottles, such as Age Repair NanoSerum and Brightening NanoSerum, are formulated separately from the sealed vial sets, in a format for daily home use.

Stability in the pack

Stability is a property of the formula in its pack. A more stable active is one that is still present, in the form the formulator intended, when the product is used. What happens once the shell releases the active is covered on Controlled release.

Stability claims on Vegalab pages are graded as formulation data. Each claim ID above links to its record in the evidence hub.

References

The studies below describe the technology in general.

1. International Council for Harmonisation. ICH Q1A(R2): Stability Testing of New Drug Substances and Products. 2003.
2. International Council for Harmonisation. ICH Q1B: Photostability Testing of New Drug Substances and Products. 1996.
3. Decher G. Fuzzy nanoassemblies: toward layered polymeric multicomposites. Science. 1997;277(5330):1232-1237.