Why we should stay tuned to nanotechnology
Art Georgalas offers some observations on current opinions on nanotechnology, an area of debate that’s unlikely to quieten down any time soon
A colleague recently suggested that what the cosmetics industry needed was its own iPod. He wasn’t referring literally to a new application for one of course but a paradigm shifting or industry transforming technology that would revitalise the cosmetics market. Nanotechnology seemed to fit that bill, until recently.
I don’t recall precisely when nanotechnology was viewed as that next wave of innovation in personal care as it has in other industries but now the term nano seems to be anathema to formulators because of concerns over negative consumer perceptions. Previously materials of this size were called submicron or simply ultrafine, and we are now returning to those terms to avoid identification by alarmist consumer groups.
We need to make the distinction here between labile nanoparticles and solid nanoparticles. Since the former are transient structures such as liposomes and nanoemulsions whose size and existence depends on their microenvironment, they are difficult to detect even when looking for them and unknown in a consumer product unless identified by the manufacturer. These are the stuff of advanced skin care active delivery systems and have evaporated from the worry lists of most regulators and consumer groups.
Solid nanoparticles, specifically those of the only two inorganic sunscreen actives, titanium dioxide and zinc oxide, are the workhorses of many broad spectrum sunscreens. These are the materials of immediate concern. With the cacophony of voices out there in industry, global regulatory bodies and NGOs, it’s getting more difficult to know where you stand on using these nanoparticles in your finished products.
So who should we be listening to? Our primary concerns are with the regulatory agencies that have legal power to restrict what goes into products, but just as important are the sources that influence public sentiment and consumer perception of what is good or bad for you. A technology or chemical can become poison to different segments of consumers based on their level of awareness and credulity. Currently there is a small segment who avoid sulfate containing shampoos and parabens in all products and a larger group of the public who would avoid PABA containing sunscreens even though they are safe and effective. The market is replete with products that are ‘free’ of one thing or another.
Last year members of the European Parliament resolved that nanoparticle containing products will be required to state such on their labels and the new regulation introduces a safety assessment procedure for all products containing nanomaterials, to apply three and a half years after being published in the EU Official Journal. This was in response to citizen petitions to limit nanotechnology use in consumer products until risks are fully determined, without concern over whether that can ever be done.
There at least appears to be a consensus on defining these nanomaterials by most involved regulators, similar to the European Parliament legislative resolution of 24 March 2009 as “insoluble or biopersistant and intentionally manufactured material with one or more external dimensions, or an internal structure (ie primary particle), on the scale from 1 to 100 nm”. Some groups propose widening this range to go down to a few angstroms and up to 200 or 300 nanometers. We can see that the scale of nano is somewhat arbitrary and tries to target a range where size matters almost more than substance. How small a material is becomes as important as what it is. We have to define boundaries to identify what we are limiting our investigations to and speak the same language in discussion of these technologies.
In the US both the FDA and EPA have joined the fray in carving out their own nano territory. This is appropriate in the case of inorganic sunscreens as they are both a topical drug active and materials that may persist in the environment.
After a public meeting hosted by the FDA in October 2006, a Nanotechnology Task Force was set up at the agency to investigate the state of the science of nanotechnology germane to the agency’s regulatory authority. A report emerged from this group less than one year later in July 2007 detailing their findings on the state of the science with regard to biological interactions with nanomaterials and analysis and recommendations for science and regulatory policy issues. Building in-house expertise as well as collaborating on efforts to further understand nano-scale materials led the summary of next steps for the agency.
Coincidentally that summer witnessed the long awaited issue of the response to comments on the FDA’s Sunscreen Final Rule that evolved into a proposed revised sunscreen rule in August 2007 to include UVA sun protection. This later draft rulemaking also included a small reference to nanotechnology, reaffirming the agency’s position that it was still on a learning curve about nanotechnology. The FDA sought input as comments and data on titanium dioxide and zinc oxide formulated in particle sizes as small as a few nanometers. It is still collecting information.
As far back as the FDA’s Final Monograph on Sunscreens in 1999, micronised titanium dioxide was judged to be safe based on the supposition that such particles were always present in the sunscreen pigments of commerce. The FDA disagreed with comments proposing that micronised titanium dioxide was a new material and declared that it was simply a grade of the active already reviewed by the OTC panel. In the recent notice of proposed rulemaking that sought to promulgate rules for UVA protection products in August 2007, the agency there put nanoparticle inorganic sunscreens in a unique position of remaining category 1 actives, safe and effective as used per OTC sunscreen and USP monographs, while requesting more intelligence on the state of the science and specifics on these two actives.
Last year also saw the EPA request comments on its proposals for analysis of case studies on titanium dioxide as a water treatment and topical sunscreen as a framework for assessment of environmental effects of nanomaterials, for which the Personal Care Products Council submitted a comment highlighting the difference between indirect environmental exposure and the direct exposure in applying sunscreen that is within the purview of the FDA. This initiative came out of recommendations in the EPA’s white paper on nanotechnology a few years earlier in 2007.
Proposals for EPA and NSF grants for studies to increase the scientific data on the fate, transport and behaviour of engineered nanomaterials in selected environmental and biological matrices closed in early February 2010, so potentially we can expect reports and data in a few years on inorganic sunscreens if they become one of the approved studies.
The current consensus after reviewing numerous studies from most of the global regulatory bodies is that nanoparticle sunscreens do not penetrate intact skin to viable tissue but remain trapped in interstitial spaces of the stratum corneum or accumulate at the follicular openings. In any case they would be sloughed off and not available to generate damaging free radicals. Often cited is the report from Australia’s Therapeutic Goods Administration that concluded from a review of 40 references in June 2009 that there is no in vivo evidence to indicate possible toxicity of nanoparticulate titanium dioxide or zinc oxide in people using sunscreens. This should allay the fears of the American Academy of Dermatology that the public may forego or limit sunscreen usage based on presumptive or preliminary information commenting on the EPA case studies proposal for topical sunscreens.
Concerns about the health risks of nanoparticles are also voiced by environmental organisations including Washington-based Friends of the Earth (FOE) and the Environmental Working Group (EWG) who continue to reprimand the FDA for not finalising regulations on sunscreens. Positions may be moderated by the need for these nanoparticles in broad spectrum sunscreens.
Consumers also look to organisations that certify ingredients and products for compliance with their environmental and safety guidelines. The major European consortium of six national organisations, Cosmos, has now issued its final standard and this includes a restriction on nanoparticles with a caveat. Using the EU definition as stated earlier it declares: “Nanomaterials are forbidden. [but] It is recognised that there may need to be exceptions and applications for exceptions supported by technical dossiers will be considered.” It understands that with many organic sun filters having also been restricted there is a limited palette of actives the formulator can work with to create sunscreens, the biggest guns in the battle against the premature ageing of the skin. Risk/benefit analysis will temper these restrictions based on the substantiated advantages of broad spectrum sun protection compared to the nebulous dangers of nanoparticle sunscreens formulated into finished products.
There will probably never be a definitive answer on questions of nanoparticle acceptability in all markets by all consumers but we need to be tuned into information disseminated by these groups and individual researchers that can sway public opinion based on faulty conclusions and counter with our own reasoned credible responses. We would also do well to continue to support studies that build a body of data on nanomaterials that are open to scrutiny and interpretation.
With all the international government agencies, environmental NGOs and self-proclaimed arbiters of natural and ecologically friendly products and practices weighing in periodically, it is hard to keep up with the status of where nanotechnology sits at any particular place in time. But as product developers we do need to monitor the activity of these groups and what the pulse of the customer is on this issue.
It will not get quiet on the global nano front any time soon and we need to keep listening.
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