Moisturizing alcohol hand sanitizers possible with stable oleosomes
The next generation of the storage spheres (Hydresia SF2) have been designed to withstand a wider range of conditions including the high alcohol levels found in hand sanitizers.
Moisturizing ingredients such as vegetable oils like safflower and almond oil are not soluble in alcohol but when encapsulated in oleosome form they can be easily suspended or incorporated into thickened alcohol formulations, vice president of research and development Dr Jack Guth explained.
“Once applied to the skin the alcohol and water in the formulation evaporate and the oleosomes dry out and collapse, releasing their contents, which in this case of SF2 is safflower oil and vitamin E,” he told CosmeticsDesign.com USA
This increased stability also means that the oleosomes can be used in the presence of ingredients such as alpha hydroxy acids (AHAs), commonly used in anti-aging and other cosmetic formulations, which have low pH values.
Applications in sun care
The company has also been developing applications for the oleosomes in sun care formulations.
According to Guth, Botaneco found that when the oleosomes were combined with both the UVB filter OMC (Octyl methoxycinnamate) and a UVA absorber the SPF value of the formula was significantly increased.
“If we mix 2 percent of the UVB absorber and 0.5 percent of the UVA filter with the oleosomes we can get to SPFs of about 30…normally you would use 15 percent of the filters for this kind of protection level,” he said.
Although the company is not totally sure of the mechanism behind this significant increase in protection, Guth said it was likely to be related to the ability of the oleosomes to absorb and protect the UVB filter which stops it from reacting with the UVA filter in the formulation.
“These two particular filters would not normally be used together as they react in such a way that reduces their protection levels,” he said.
‘Transient emulsification’
A further characteristic of the oleosomes that could benefit personal care formulators is their ‘transient emulsification’ characteristics.
“Transient emulsification means you have an emulsifying effect when you want it and not when you don’t,” said Guth.
In other words the oleosomes will provide an emulsifying effect when they are added during formulation. However, when they dry out on the skin surface they collapse and the protein responsible for the emulsifying characteristic, which is on the oleosome surface, is no longer able to do its job.
Disabling the emulsifier in this way eliminates the disruption of skin lipids which has been observed with some emulsifiers and also improves the ability to waterproof the formulation, Guth explained.
