18 HYGIENE 150 p=0.02 p=0.04 100 50 0 Day 0 Day 8 Day 18 100 50 0 Day 0 Day 8 Day 18 100 50 0 TEWL Figure 3: TEWL reduction after treatment with urea-containing creams (left, centre) & skin irritation after addition of SLS (right)
alcohol because the surfactants in soaps can not only irritate the skin to varying degrees but also leave irritating residues on the surface of the skin. That said, different types of alcohols also raise problems, causing an increase in redness, dryness and TEWL. So, what to do to address this? Lodén and co-workers took their
inspiration from the creams containing emollients, with or without humectants, that are used to treat dry skin. There are some caveats here, in that the instruments used to measure skin hydration can give false readings, while skin creams can both improve or worsen the skin barrier in sensitive skin, according to the literature. Canoderm and calmuril, with 5% and 10% urea respectively, are among those that markedly reduce TEWL. Likewise, creams may either increase or
decrease sensitivity to sodium lauryl sulfate (SLS), a known irritant surfactant, in healthy skin. Here, again, the creams containing 5% and 10% urea are among those that decrease TEWL and thus reduce irritation, whereas others with high glycerin, lipid and vegetable oil have been known to have the opposite effect (Figure 2). Other studies, Lodén continued, have
shown aqueous cream BP to disrupt the skin barrier, reduce skin thickness and increase TEWL. Olive oil and sunflower oil have been shown to reduce skin thickness, while the former can also disrupt the skin barrier function, possibly by releasing oleic acid. However, her work with urea over many years, as well as by other researchers, has shown that it can improve the barrier function in both sensitive and healthy skin. Over the years, Eviderm has carried out
studies of the use of urea to prevent a relapse in patients who had previously suffered from eczema. They measured those who used a moisturising cream containing 5% urea over six months against a passive control group who used nothing. This established that the urea cream significantly delayed a relapse in hand eczema, in atopics and when compared to a reference cream (Figure 3). Theorising that this effect might also work in hand sanitisers, in 2020 Lodén mixed 5% urea into a formulation, both with and without the addition of niacinamide and propanediol,
PERSONAL CARE March 2022
and asked people to use it for 19 days. At this point she measured TEWL and found that both formulations reduced it. She also carried out a challenge test with SLS in a 70% alcohol formulation containing urea and found that both TEWL and redness were reduced.
Regulatory challenges However, Lodén said, there are still challenges in the development of alcohol hand sanitisers. To start with, ethanol is not yet an approved ‘active’ biocidal substance under the BPR. There is a high likelihood that it will be approved but one reason this has already taken so long is that ethanol may be classified as a carcinogen. As and when it is approved, formulators will have to apply to register any alcohol-containing sanitisers. In addition, hand sanitisers often need
to contain >70% alcohol and this leaves little space for additives. Additives may change the formulation’s cosmetic properties, stability and disinfectant power; glycerin, in some studies, lowers activity against SARS-CoV2. Moreover, Article 19 of the BPR specifies
that a biocidal formulation “shall not contain any non-active substance that may not be included in a cosmetic product pursuant to Regulation (EC) No 1223/2009”, so this must also be taken into account. The ‘pros’ for urea, in Lodén’s view, is that
it is usable as a cosmetic ingredient, it can improve the barrier function and it enhances disinfectant power. The ‘cons’ are that it increases pH during degradation if it cannot be stabilised; and it destabilises polymers and gel structure over time. Worse still, urea together with ethanol makes ethyl carbamate, which is classified as a carcinogen and may cause skin cancer – even though it is also found in food. “The good news is that you can develop
alcohol hand products that can deliver hygiene and a healthy skin,” Lodén concluded. “But you need to control the efficacy, safety, stability and marketing. I think the future will be an increased focus on stability rather than simply writing percentages on the packaging. And I think there will be many more borderline issues as other regulatory entities come into the cosmetics space. Understanding pharmacological modes of actions could be quite a tricky thing.”
Both Lodén and consultant Dr Mojgan
Moddaresi of Personal Care Regulatory stressed the need for producers of hand sanitisers to take care when it comes to claims and regulation. These points may become increasingly important if the line between different products become blurred. The latest guidance from the EU’s Scientific Committee on Consumer Safety (SCCS), in November 2020, is that the following labelling elements would not support a main cosmetic function of leave-on hydro alcoholic hand gel: ■ Antibacterial, antimicrobial, antiviral, virucide, antifungal (and their attributes, such as ‘antiviral properties’, ‘antibacterial ingredients’ or ‘inhibits bacterial growth’) ■ Disinfecting, disinfectant, disinfection, sanitiser, sanitising ■ Antiseptic ■ Kills X% bacteria/viruses/microbes ■ Decontaminating ■ Formulation recommended by the WHO ■ Anti-COVID-19, anti-coronavirus, anti-SAR Moddaresi said that she had noted a
significant increase in misinformation about claims in the past year, particularly with regards to cosmetic ingredients in creams claiming to protect users from COVID. With a large number of producers formulating hand sanitisers, some “wanted to be creative and use innovative ingredients”. The safety of some of these, like gold nanoparticles, is under question and they had not been approved by the SCCS. Two common claims that risked falling fall
of regulations, said Moddaresi, are ‘anti-viral’, which is not a cosmetic claim and cannot be used on products that fall under cosmetic product classification, and protection from COVID. This would bring the product into the medical category. Personal Care Regulatory also noted a growing number of claims about social responsibility in the past two years, raising wider issues of advertising standards. “If you say ‘hand wash’, it is a cosmetic. If
you say ‘antibacterial hand wash’, you need to have EN 1499 and it may go under the BPR. If you have hand sanitiser,” it is definitely biocidal and you have to make sure you do the right testing,” she said. “Make sure that you don’t spread misinformation and hopefully we can keep consumers safe and our products at the highest quality level.”
Redness p=0.07 p=0.02 150 150
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