Microencapsulation: how packaging ingredients into tiny capsules could benefit your skin

Daniel Judd BSc, MBiol

Good things may now come in small skincare packages. Daniel Judd looks at how packaging ingredients into micro-capsules could benefit your skin.

There’s a quiet revolution going on at a cosmetics counter near you. You may have heard the buzzword – micro-encapsulation. It’s a big word for packaging ingredients into tiny capsules that will either better preserve or release ingredients into the skin in a very different way from what we’re used to.

Cosmetics can be tricky things to build. Many of the ingredients you love, your antioxidants, your vitamins, your nutrients and your fragrances all have problems that limit just how well they can actually work in a product. Some oxidise, some are unstable and some wont make it across the skin barrier. Sometimes these problems can be partially solved by packaging, chemical modifications, adding additional ingredients and preservatives, but these can sometimes limit the effectiveness of the product, add either extra costs or increase the extra risk of adverse reactions.

So, necessity being the mother of invention has lead scientist to come up with a new technique that might offer a better solution for many ingredients – microencapsulation.

In general active ingredients in skincare products are mixed together so that each is free to move around, but microencapsulation – as its name suggests – creates tiny shells around the active ingredients, sealing them away and keeping them safe until they are needed.

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These shells can be made from a wide range of materials, with popular biological ones including sugars, proteins and oils. There are also synthetic polymers that can be used to form this capsule shell as well. All of these options are usually well tolerated by the body with few recorded adverse reactions as a result  the process of microencapsulation. These shells are a clever way to trick the skin into letting a molecule through it that would otherwise be stopped at the surface, but without modifying the ingredients inside.  Many ingredients like vitamin C need to get past these outer layers of your skin so they can reach the collagen producing fibroblast cells below.

 

Tricking the skin

So how do the ingredients get out when you need them? This can vary between capsules but each method allows for the specific release of the ingredient once it hits your skin and not before.

One method keeps the ingredient locked up tight at room temperature and below but once they get warmed up to body temperature as they are rubbed into your skin, they break open and release the ingredients inside.

A similar method makes the capsule sensitive to the difference in acidity between the capsules and your skin which is slightly acidic.

More specific techniques can use the digestive enzymes found on your skin thanks to the mix of harmless bacteria that live there. Enzymes called proteases chop proteins down into individual amino acids, lipases digest fats and amylases digest sugars. These enzymes chop the capsule apart, releasing the ingredients once they’re on your skin and protecting them until that point.

One last method uses microcapsules that are sensitive to the pressure generated by rubbing the product into your skin. While stored, the capsules hold the ingredient inside but the application of the product will squash and break them open.

All these methods of release are dependent on the exact makeup of the capsule but each of them is suitable for releasing a product once it hits the skin.

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Ingredients that benefit

There are a few things that determine which of these would be good for a particular ingredient, the major one being how the capsule interacts with both the ingredient inside and the rest of the cosmetic product outside. Some ingredient-capsule combinations aren’t possible as the capsule might react with and destroy the ingredient inside it while others might not actually stop the ingredients from escaping, making it useless as a containment method.

Vitamin C is a great example of an ingredient being made even by better by microencapsulation. Vitamin C is an antioxidant vitamin used in anti-aging and anti-photodamage wrinkle fighting products. Once inside the skin it helps build more collagen and protects that collagen from any further damage by things like UV rays and pollution.

The problem is that vitamin C is very unstable and will quickly convert into its useless oxidised form when exposed to air, moisture, heat or sunlight. It also isn’t great at getting into the skin and needs the cream to be at a specific acidic pH before it can be easily absorbed. Studies have shown that microencapsulation of vitamin C can improve the shelf life of the product and also increase the penetration of it into the layers of the skin. The microcapsules were also shown to readily the release the vitamin C when needed.

Vitamin A, like vitamin C, also struggles with stability issues in air and sunlight which can be improved by microencapsulation. Also known as retinol, vitamin A is another antioxidant vitamin that can improve the appearance of wrinkles and damaged skin when applied topically. The problem with vitamin A is the relatively common side effects that cause people who could otherwise benefit from it to break out with red, flaky and burning skin. Microencapsulation can help here too since the capsules can be designed for a slower release of their contents which has been shown to reduce the negative side effects of vitamin A.

 

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Is it all good news?

All these advances have kept scientists on their toes as microencapsulated products aren’t without their downsides. One of those is that the same technology that lets the capsule open when needed can also open up the possibility for premature release thanks to environmental conditions. Capsules designed to open at body temperature can partially open and leak their contents at in hotter climates. Pressure sensitive capsules may pop if stacked or packed too tightly and the same pressures can cause other types of capsule to glue together and gum up. Some capsule materials can bind onto water and in humid environments then can overdo it and burst from all the water they pick up. Low humidity can cause ingredients that need a little water inside the capsule to dry up as the water evaporates out of the capsule.

Then there are the challenges faced by capsule’s building materials – the protein, sugar and oil.  All of them offer a great food source to invading bacteria and microbes, making encapsulated ingredients a target for spoiling and mould formation. All of these pose challenges for formulators and may affect the shelf-life of the products you buy.

That said, microencapsulation is an exciting new prospect for improving many cosmetic ingredients and boosting their potential beyond what was previously possible. With no major downsides and prices that are often similar to  their non-encapsulated version, it could well be worth checking out if your favourite skin care ingredients comes in its own tiny package.

 

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