Cyclodextrin for active cosmetics molecules

Cyclodextrin (CD) acts as an active carrier through molecule encapsulation, adding many interesting properties to enhance cosmetics ingredients and products.

Cyclodextrin is made from potato starch, readily biodegradable and harvested from renewable and lasting sources.

Cyclodextrin is a host molecule (1) able to entrap an apolar guest molecule (2).

This creates a new entity also called inclusion compounds.

What are the benefits of Cyclodextrin?

The entrapped molecule gains several traits and properties that can positively improve the cosmetic products and fragrances.

Cyclodextrin acts as:

• An active solubilizer.
  Cyclodextrin solves difficulties with aqueous solubility. This is especially the case with retinol, liposoluble vitamins, vegetable oils, fatty acids and their esters, menthol, preservatives, etc. Looking closer at menthol, it is used as a cooling agent in cosmetics. Cyclodextrin enhances the solubility in aqueous form and avoids using alcohol.
• A defender.
  By preventing the decomposition and oxidation of the embedded molecule due to light, heat, UV and chemicals, it is improving the shelf life of actives and fragrances.
  Perfect match for molecule like oils, dyes, hydroquinone, natural tocopherol, kojic acid, etc. For retinol (used in topical anti-ageing and anti-wrinkles), Cyclodextrin prevents oxidation and formation of peroxidic toxic intermediates, while enhancing solubility in aqueous form.
• A stabilizer.
  Cyclodextrin can improve the compatibility with the other ingredients of the cosmetics formulations.
• A carrier.
  It improves the release properties and increases the bioavailability of actives, it also reduces the volatility of the encapsulated molecules (especially perfumes).
• An odor neutralizer.
  Cyclodextrin molecules are used to mask bad smells; helpful in formulations containing dihydroxyacetone, glutathione, mercaptan and to eliminate sweat malodor (body secretion like tiols, steroid, hexenal, octenal and nonenal, etc).
• A skin protector against irritation.
  It decreases or prevents skin irritation from tea tree oil, limonene, p-cymene. Salicylic acid used in keratolytic and antibacterial products. Cyclodextrin enhances the solubility and reduces the irritant action.

How does Cyclodextrin work?

Due to its toroidal shape structure, Cyclodextrin allows the formation of molecular inclusion complexes with a wide variety of molecules by entrapping them entirely, or at least partially, both branched as well as unbranched.

Guest molecules are hydrophobic and have generally very low solubility in water. Only substrates that are less polar than water may form inclusion complexes with Cyclodextrins.

Representation of molecular encapsulation possibilities 

Depending on the size, the structural shape and the conformation of the guest molecules and the quantity of cyclodextrin, 2:1, 1:1 and 1:2 molecular inclusion complexes can be formed. It is noted that 1:1 molecular inclusion complexation is the most common form.

Cyclodextrin and Hydroxypropyl Cyclodextrin

The are two multifunctional types of Cyclodextrins with specific functional benefits suited for different applications.

Cyclodextrin

Cyclodextrin being a crystalline powder and having a very low solubility in cold water is adapted for dry powders formulas or dispersions: dry shampoos, deodorants in spray, fine perfumes, bath bomb / salt, soaps bar, etc.

Hydroxypropyl Cyclodextrin

Hydroxypropyl Cyclodextrin being an amorphous powder, with a very high solubility in water as well as in ethanol-water blends, is adapted for liquid forms, emulsions and perfumes.

For all these possibilities, the Cyclodextrin and Hydroxypropyl Cyclodextrin are already available and ready to use in hundreds of cosmetic products today.