Preservatives are not the same as silicones, but they do have some commonalities. They also happen to be targets of clean beauty and ‘free-from” movements. While both are subject to scrutiny from consumers over environmental and human safety concerns, they have very different functions. Multi-benefit ingredients can be created to address multiple unmet needs in formulation design as the ingredient toolbox changes in response to legislators, consumers, and retailers.
The alternative preservation category, comprised of multifunctional ingredients that replace controversial preservatives like methylparaben or methylisothiazolinone (MIT), has seen a surge in the past decade. Caprylyl glycol and ethylhexylglycerin are popular choices, often combined with a fungicide such as sodium benzoate. These ingredients are safe, effective and widely accepted by consumers. They are often petroleum-derived, and have a multifunctional benefit, such as e.g.
These ingredients are used to condition the skin and can be supplemented with other ingredients. This addresses a significant unmet demand for safe and effective preservation but does not address the need for increased sustainability. Additional ingredients are needed to resolve other unmet formulation requirements.
The solution is: Silicone replacement meets microbiological control
Methylheptylglycerin is a patent-pending, novel chemistry that offers two distinct benefits.
- Inhibition of microorganisms
- Emulsion anti-soaping
This medium chain glycerylether is biobased 100% from sustainably sourced feedstocks. It is readily biodegradable and designed with green chemistry. It is unique in its ability to offer high-value benefits in preservation and emulsion aesthetics.
Natural cosmetic preservation effect
As part of a comprehensive preservation strategy that follows Hurdle Technology’s industry convention, Lexgard(r), MHG Natural MB protects formulations against microbial growth. Multiple barriers are used in manufacturing and formulation to prevent microorganisms from surviving and multiplying.
Lexgard(r), Natural MHG MB, is a primary bacteriostatic ingredient that inhibits the growth of yeast and bacteria in formulations. The effectiveness of Lexgard(r) Natural MHG MB was shown to be effective at levels ranging from 0.5 to 1.5% (w/w), in multiple formulation types, including emulsions and surfactant-based systems as well as wipes and sheet mask juice formulations. Efficacy is determined as satisfying the Pass criteria for the S. Aureus (bacteria), E.coli (bacteria), P. aeruginosa(bacteria) and C. albicanss (yeast) according the industry standard preservative effectiveness test methods: PCPC (EP-A), and USP51. Combining Methylheptylglycerin with the fungistatic agent Caprylhydroxamic Acid can produce broad spectrum preservation effects. This combination (Spectrastat(tm), MHG Natural MB), is a cold-processable liquid that’s effective between pH 4 and 8.
Natural anti-soaping in Emulsions
Methylheptylglycerin can reduce or eliminate soaping and whitening effects often experienced during the rub in phase of emulsion application. It has been proven to decrease or eliminate soaping/whitening in anionic and nonionic oil-in water (O/W), emulsion bases. This effect has been reduced or eliminated by silicones. It is now possible to create formulations that are natural and/or without silicone with superior aesthetics.
A cationic emulsion was used to demonstrate the anti-soaping effects of Lexgard(r), Natural MHG MB. This was done using a graded visual assessment. The test articles were applied on the volar forearm. The following swipe ends were used to collect images: 4, 8, and 12. These images were then sent to graders for their evaluation. On a scale from 0 to 5, where 0 means no soaping and 5 means high soaping, the graders scored each image.
The study included the following articles: emulsion with 2%, w/w Lexgard(r), MHG Natural MB (natural-anti-soaping). Emulsion containing 0.5% (w/w), dimethicone-20cSt (silicone-anti-soaping). Emulsion with 5% (w/w), dimethicone20cSt (positive controls). Negative control: emulsion without anti-soaping agents. At both the 4 and 8 swipes ends, the natural anti-soaping lotion with 2% (w/w), Lexgard(r) MHG MB had less soaping than that containing silicone anti-soaping cream. The natural anti-soaping cream containing Lexgard(r), Natural MHG MB did not cause soaping at the 12 swipes point. The statistically equivalent result to the positive control using 5% (w/w), dimethicone-20cSt, and the silicone antisoaping lotion with 0.5% (w/w), dimethicone-20cSt was achieved.
Visual graders were also used to evaluate the soaping effect in an ultra-high soaping anionic solution. Due to the extremely high soaping quality of this base emulsion, an additional 20-swipes point was used in this evaluation. The emulsion that contained 2% (w/w), Lexgard(r), Natural MHG MB did not show soaping at the 20-wipes point. However, the emulsion that contained 2% (w/w), dimethicone (20cSt) still had visible soaping effects.
Lexgard(r), MHG Natural MB, a novel innovation in medium-chain glyceryl ethers, brings to market an ingredient that is 100% biobased from sustainably sourced feedstocks. It has been designed and manufactured using green chemistry and offers multiple benefits for formulations. This ingredient is a breakthrough in the industry by offering a sustainable and natural route to formulation in two high-demand areas using one ingredient: silicone replacement and microbial control.