With potential upcoming European regulations limiting the use of volatile cyclomethicones in leave-on applications combined with the strong demand from customers and consumers to use bio-based and biodegradable materials, there is a need for new biodegradable carriers acting as alternatives to cyclomethicones using sustainable feedstocks. Levulinic acid ketal derivatives, specifically Ethyl PG-Acetal Levulinate (EPAL) can be used as a medium volatility carrier in leave-on skin care formulations in place of cyclomethicones and fossil hydrocarbons, providing additional unique performance due to a higher polarity. This 100% renewable carbon fluid is produced by the conversion of biomass such as softwood, bagasse, post-consumer wood and is ultimately biodegradable.
The purpose of this paper is to share how a novel levulinic ketal derivative can be used in leave-on applications as an alternative to cyclomethicones, fossil-based hydrocarbons and other oils as well as bringing additional properties and new formulation possibilities.
The following evaluations were performed:
Volatility profiles at room and skin temperature (32°C).
Sensory comparisons with cyclomethicones and organic fluids using an experienced Dow internal panel
Comprehensive compatibility study with a broad range of cosmetic materials including fragrances, cosmetic actives, and sunscreens and this at several ratios
Cleansing properties for waterproof color cosmetics
Dispersion and suspension of pigments
Formulation in o/w and w/o emulsions, sticks, foundations.
From a volatility perspective, 20 % of the EPAL evaporates after 6 hours at 32°C, defining a medium volatility carrier. Although this is a significantly lower volatility compared to cyclopentasiloxane (D5), when applied in-vivo on the forearm, this lower volatility only has an impact on the absorption parameter, being slower than D5, making this material an optimum choice for leave-on skin care formulations where longer play time is desirable but without leaving any greasy film residue.
EPAL is quite polar (Hansen polar parameters: δP:~13; δH: ~8) resulting in an overly broad compatibility profile. It is compatible with most organic oils and esters and even silicone fluids except for the high molecular weight silicone polymers. The most interesting is the high compatibility with fragrances (like ethanol), cosmetic actives such as Co-enzyme Q10 and sunscreens such as avobenzone. This compatibility also makes it a good makeup remover for waterproof lipsticks and mascara, an area where cyclomethicones and fossil-based hydrocarbons are universally used.
It also showed better wetting and suspension for non-treated, lower cost pigment, an advantage for mineral based color cosmetics that preferably use non-chemical pigment treatments.
Several formulations containing EPAL will be illustrated, demonstrating the versatility of this novel material across different leave-on skin product formats including facial care, body care, AP deo and color cosmetics.
EPAL is a 100% renewable carbon-containing novel cosmetic carrier fluid using by-products from wood and sugar production. It has medium volatility and a similar sensory profile when compared to cyclopentasiloxane, making it a potential alternative to existing carriers. The unique polarity results in a broad compatibility profile thus permitting novel natural-based formulations for delivering fragrances, cosmetic actives, and sunscreens. Being sourced from sustainable feedstocks, EPAL is biodegradable and has a good safety profile, making this carrier ideal for the formulation of very high naturally index compositions without compromising texture, sensory and performance.