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Too small for concern? Public health and nanotechnology

Too small for concern? Public health and nanotechnology N anotechnology promises to transform market sectors, delivering benefits for consumers and commercial gains to industry. The health care sector, in particular, has been a target of nanotechnology research and development (R&D) spending, with projected health‐related benefits postulated to include enhancements to conventional therapeutic goods, the development of innovative targeted drug delivery systems, and disease diagnosis systems such as ‘lab‐on‐a‐chip’ technology. Conceptually, nanotechnology refers to the ability to control the composition of molecules and atoms within the range of 1.00–100 nm. At this scale, many materials exhibit novel properties when compared with their micro or macro‐sized equivalents, including, for example, chemical reactivity, strength, mobility and solubility. The scale is almost incomprehensible, with the width of a strand of DNA estimated to be 2 nm, while the width of a red blood cell is estimated to be 7000 nm (or 7 μm). The magnitude of investment in nanotechnology R&D is in stark contrast to the scale of the technology itself, with global investment in 2005 alone estimated to be $US9.6 billion. While many of the potential aesthetic and functional benefits may be some years off, a more immediate and pressing concern is the increasing number of consumer products containing nanoparticles that have already penetrated the therapeutic and cosmetics sectors. There is preliminary evidence to suggest that some engineered nanoparticles may display unanticipated toxicological and ecotoxicological properties, and may therefore pose a risk to human and environmental health and safety. Even at this early stage, nanotechnology represents a challenge to national regulatory frameworks and could very well present as a future public health concern. This paper sets out to briefly explore concerns about engineered nanoparticles within the context of drug and chemical regulation. Current approach Despite the novel properties exhibited at the nanoscale, Australia's national chemical regulatory schemes, which include the National Industrial Chemicals and Assessment Scheme (NICNAS) and the Therapeutic Goods Administration (TGA), do not at this stage distinguish between the different forms of a chemical on the basis of their size. In practice, this means that where an active nano‐scale ingredient, such as zinc oxide (ZnO), is incorporated into a cosmetic product and the active ingredient is already listed in its macro or micro‐scale form on the Australian Inventory of Chemical Substances, the nano‐scale ingredient will be considered by the regulator, NICNAS, to be an ‘existing’ chemical, despite nanoparticles potentially exhibiting unique physiochemical, toxicological and ecotoxicological properties. In this instance, the manufacturer or the importer of the cosmetic would not be required to notify the regulator of the nano‐based cosmetic, nor would the nano‐based cosmetic be required to be assessed by the regulator on the basis of its toxicity in relation to human and environmental safety. Likewise, it would appear that where a sunscreen has been reformulated to contain an active nano‐scale ingredient such as ZnO or titanium dioxide (TiO 2 ) – both of which are listed medicines on the Australian Register of Therapeutic Goods – the nano‐scale ZnO and TiO 2 would be considered to be an existing medicine by the TGA and therefore fail to trigger regulatory testing. This situation is not unique to Australia, with no federal government in the world having to date amended legislation to specifically ‘capture’ nanotechnology or enacted broader nano‐specific legislations. Yet while consumer use of cosmetics and sunscreens containing nanoparticles increases, scientific debate surrounding the ability of nanoparticles contained in topical lotions to permeate the epidermal layer and enter the blood stream, and the subsequent consequences that this could engender, is intensifying. Leading global re‐insurance company Swiss Re notes, for instance, that “studies carried out to date have reached no agreement as to whether nanoparticles can, in fact, be absorbed via the skin”. In contrast, a review of the scientific literature on sunscreens containing nanoparticles by the TGA concluded that “the weight of current evidence is that they [nanoscale particles] remain on the surface of the skin and in the outer dead layer (stratum corneum) of the skin”. Such debate highlights the uncertainties that exist in relation to unlabelled, commercially available products incorporating nanoparticles. Too small for concern? The critical question is, should we be concerned? Do engineered nanoparticles present new or unquantifiable risks from a public health perspective? At this point in time, the short answer is that scientific experts simply do not know, with Aitken, Creely and Tran having stated that “current knowledge is inadequate for risk assessment”. There is, however, some cause for concern, with the emergence of some research suggesting that some nanoparticles could potentially pose a risk to human health. Net et al. have stated that “as the particle size shrinks, there is a tendency for pulmonary toxicity to increase, even if the same material is relatively inert in bulkier form (e.g., carbon black and TiO 2 )”. This is perhaps best illustrated by reference to carbon nanotubes (CNTs), which are thin tubes comprising graphene sheets with a typical diameter of 1 nm. While CNTs naturally occur in nature, they are being manufactured for use within the electronic and automobile industries and have been speculated to offer a wide range of potential applications across the health and personal care sectors, including, for example, as a vehicle for drug delivery. Despite the limited number of toxicology and immunotoxicity studies that have been undertaken on CNTs to date, preliminary studies suggest that these engineered nanoparticles are capable of producing inflammation responses and toxicological changes in the lungs of rodents, while other studies have shown that CNTs may induce oxidative stress within skin cells. When CNTs are fixed into a solid matrix they may not pose any new risks; however, the same cannot be said with any certainty about free CNTs. Despite these concerns, products incorporating nanoparticles continue to make their way into the marketplace as multinational companies such as L'Oreal, Lancôme, BASF and DuPont attempt to recoup their investments in nanotechnology R&D. In the context of an absence of comprehensive regulatory risk assessments, concerns over the appropriateness of existing methods to assess potential risks of nanoparticles, and the emergence of gaps within regulatory regimes, the following key question remains: should regulatory agencies adopt a more pre‐emptive or precautionary approach to engineered nanoparticles? This question is particularly pertinent following earlier regulatory failures and the public health costs associated with ‘wonder drugs’ such as thalidomide and Vioxx, and materials such as asbestos. Importantly, any regulatory response must be balanced against the broader societal and economic implications of regulating some aspects of the platform technology when faced with such scientific uncertainty. Yet as history reminds us, a failure to recognise the early warning signs and respond accordingly may have significant public health ramifications. The European Commission's (EC) Scientific Committee on Emerging and Newly Identified Health Risks has clearly embraced the idea of a pre‐emptive response, suggesting that “in the absence of suitable hazard data a precautionary approach may need to be adopted for nanoparticles which are likely to be highly biopersistent in humans and/or in environmental species”. One potential way of balancing the significant public health benefits of this powerful and promising technology against potential risks may be to look towards the European Union's (EU) comprehensive new chemical regime, Registration, Evaluation, and Authorisation of Chemicals (REACH) Regulation. REACH, which is expressly underpinned by the precautionary principle, has shifted the burden of proof about the substance's safety back on to the industry itself. A cornerstone of REACH is that it does not differentiate substances on the basis of ‘existing’ or ‘new’ chemical substances, and requires a manufacturer, importer or producer of a substance to register and complete a technical dossier on all substances over a specified tonnage level before they can have access to the EU market. In practical terms, such requirements may slow down the time to market for new products, while at the same time placing a substantial economic burden on industry. However, the EC considers that this cost must be weighed against the need to protect public and environmental health and safety. Conclusion Overall, this paper argues that sufficient uncertainty exists over the potential toxicity and ecotoxicity of engineered nanoparticles, some of which are already being incorporated into commercially available products, to warrant revisions to Australia's regulatory frameworks. While such action may be viewed as being pre‐emptive or precautionary, this promising technology must be regulated in such a way that ensures that the expected benefits are not overshadowed by the potential risks. One way to minimise the potential risks without stifling the technology's social or economic promise and ensuring public confidence would be for regulatory agencies to distinguish between engineered nanoparticles from their ‘existing’ micro or macro‐scale counterparts. In doing so, the nanoscale ingredients would be considered to be a ‘new’ chemical or medicine under these frameworks, thereby triggering regulatory testing procedures. This approach would be a compromise between the present regime and the precautionary approach that is being introduced into the EU under REACH. However, it is recognised that this approach may not in itself address concerns over the appropriateness of the usual risk assessment methods for determining the potential risks of engineered nanoparticles. From a public health point of view, there is clearly a need for the international community to determine the appropriateness of testing regimes. Only when these critical knowledge gaps have been addressed will government, industry and scientists better appreciate the potential risks associated with nanoparticles and thereby act accordingly. As evidenced by the regulatory failures of thalidomide and asbestos, the only problem is that the costs associated with any delay may be too great. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian and New Zealand Journal of Public Health Wiley

Too small for concern? Public health and nanotechnology

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Publisher
Wiley
Copyright
Copyright © 2007 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1326-0200
eISSN
1753-6405
DOI
10.1111/j.1753-6405.2007.00092.x
Publisher site
See Article on Publisher Site

Abstract

N anotechnology promises to transform market sectors, delivering benefits for consumers and commercial gains to industry. The health care sector, in particular, has been a target of nanotechnology research and development (R&D) spending, with projected health‐related benefits postulated to include enhancements to conventional therapeutic goods, the development of innovative targeted drug delivery systems, and disease diagnosis systems such as ‘lab‐on‐a‐chip’ technology. Conceptually, nanotechnology refers to the ability to control the composition of molecules and atoms within the range of 1.00–100 nm. At this scale, many materials exhibit novel properties when compared with their micro or macro‐sized equivalents, including, for example, chemical reactivity, strength, mobility and solubility. The scale is almost incomprehensible, with the width of a strand of DNA estimated to be 2 nm, while the width of a red blood cell is estimated to be 7000 nm (or 7 μm). The magnitude of investment in nanotechnology R&D is in stark contrast to the scale of the technology itself, with global investment in 2005 alone estimated to be $US9.6 billion. While many of the potential aesthetic and functional benefits may be some years off, a more immediate and pressing concern is the increasing number of consumer products containing nanoparticles that have already penetrated the therapeutic and cosmetics sectors. There is preliminary evidence to suggest that some engineered nanoparticles may display unanticipated toxicological and ecotoxicological properties, and may therefore pose a risk to human and environmental health and safety. Even at this early stage, nanotechnology represents a challenge to national regulatory frameworks and could very well present as a future public health concern. This paper sets out to briefly explore concerns about engineered nanoparticles within the context of drug and chemical regulation. Current approach Despite the novel properties exhibited at the nanoscale, Australia's national chemical regulatory schemes, which include the National Industrial Chemicals and Assessment Scheme (NICNAS) and the Therapeutic Goods Administration (TGA), do not at this stage distinguish between the different forms of a chemical on the basis of their size. In practice, this means that where an active nano‐scale ingredient, such as zinc oxide (ZnO), is incorporated into a cosmetic product and the active ingredient is already listed in its macro or micro‐scale form on the Australian Inventory of Chemical Substances, the nano‐scale ingredient will be considered by the regulator, NICNAS, to be an ‘existing’ chemical, despite nanoparticles potentially exhibiting unique physiochemical, toxicological and ecotoxicological properties. In this instance, the manufacturer or the importer of the cosmetic would not be required to notify the regulator of the nano‐based cosmetic, nor would the nano‐based cosmetic be required to be assessed by the regulator on the basis of its toxicity in relation to human and environmental safety. Likewise, it would appear that where a sunscreen has been reformulated to contain an active nano‐scale ingredient such as ZnO or titanium dioxide (TiO 2 ) – both of which are listed medicines on the Australian Register of Therapeutic Goods – the nano‐scale ZnO and TiO 2 would be considered to be an existing medicine by the TGA and therefore fail to trigger regulatory testing. This situation is not unique to Australia, with no federal government in the world having to date amended legislation to specifically ‘capture’ nanotechnology or enacted broader nano‐specific legislations. Yet while consumer use of cosmetics and sunscreens containing nanoparticles increases, scientific debate surrounding the ability of nanoparticles contained in topical lotions to permeate the epidermal layer and enter the blood stream, and the subsequent consequences that this could engender, is intensifying. Leading global re‐insurance company Swiss Re notes, for instance, that “studies carried out to date have reached no agreement as to whether nanoparticles can, in fact, be absorbed via the skin”. In contrast, a review of the scientific literature on sunscreens containing nanoparticles by the TGA concluded that “the weight of current evidence is that they [nanoscale particles] remain on the surface of the skin and in the outer dead layer (stratum corneum) of the skin”. Such debate highlights the uncertainties that exist in relation to unlabelled, commercially available products incorporating nanoparticles. Too small for concern? The critical question is, should we be concerned? Do engineered nanoparticles present new or unquantifiable risks from a public health perspective? At this point in time, the short answer is that scientific experts simply do not know, with Aitken, Creely and Tran having stated that “current knowledge is inadequate for risk assessment”. There is, however, some cause for concern, with the emergence of some research suggesting that some nanoparticles could potentially pose a risk to human health. Net et al. have stated that “as the particle size shrinks, there is a tendency for pulmonary toxicity to increase, even if the same material is relatively inert in bulkier form (e.g., carbon black and TiO 2 )”. This is perhaps best illustrated by reference to carbon nanotubes (CNTs), which are thin tubes comprising graphene sheets with a typical diameter of 1 nm. While CNTs naturally occur in nature, they are being manufactured for use within the electronic and automobile industries and have been speculated to offer a wide range of potential applications across the health and personal care sectors, including, for example, as a vehicle for drug delivery. Despite the limited number of toxicology and immunotoxicity studies that have been undertaken on CNTs to date, preliminary studies suggest that these engineered nanoparticles are capable of producing inflammation responses and toxicological changes in the lungs of rodents, while other studies have shown that CNTs may induce oxidative stress within skin cells. When CNTs are fixed into a solid matrix they may not pose any new risks; however, the same cannot be said with any certainty about free CNTs. Despite these concerns, products incorporating nanoparticles continue to make their way into the marketplace as multinational companies such as L'Oreal, Lancôme, BASF and DuPont attempt to recoup their investments in nanotechnology R&D. In the context of an absence of comprehensive regulatory risk assessments, concerns over the appropriateness of existing methods to assess potential risks of nanoparticles, and the emergence of gaps within regulatory regimes, the following key question remains: should regulatory agencies adopt a more pre‐emptive or precautionary approach to engineered nanoparticles? This question is particularly pertinent following earlier regulatory failures and the public health costs associated with ‘wonder drugs’ such as thalidomide and Vioxx, and materials such as asbestos. Importantly, any regulatory response must be balanced against the broader societal and economic implications of regulating some aspects of the platform technology when faced with such scientific uncertainty. Yet as history reminds us, a failure to recognise the early warning signs and respond accordingly may have significant public health ramifications. The European Commission's (EC) Scientific Committee on Emerging and Newly Identified Health Risks has clearly embraced the idea of a pre‐emptive response, suggesting that “in the absence of suitable hazard data a precautionary approach may need to be adopted for nanoparticles which are likely to be highly biopersistent in humans and/or in environmental species”. One potential way of balancing the significant public health benefits of this powerful and promising technology against potential risks may be to look towards the European Union's (EU) comprehensive new chemical regime, Registration, Evaluation, and Authorisation of Chemicals (REACH) Regulation. REACH, which is expressly underpinned by the precautionary principle, has shifted the burden of proof about the substance's safety back on to the industry itself. A cornerstone of REACH is that it does not differentiate substances on the basis of ‘existing’ or ‘new’ chemical substances, and requires a manufacturer, importer or producer of a substance to register and complete a technical dossier on all substances over a specified tonnage level before they can have access to the EU market. In practical terms, such requirements may slow down the time to market for new products, while at the same time placing a substantial economic burden on industry. However, the EC considers that this cost must be weighed against the need to protect public and environmental health and safety. Conclusion Overall, this paper argues that sufficient uncertainty exists over the potential toxicity and ecotoxicity of engineered nanoparticles, some of which are already being incorporated into commercially available products, to warrant revisions to Australia's regulatory frameworks. While such action may be viewed as being pre‐emptive or precautionary, this promising technology must be regulated in such a way that ensures that the expected benefits are not overshadowed by the potential risks. One way to minimise the potential risks without stifling the technology's social or economic promise and ensuring public confidence would be for regulatory agencies to distinguish between engineered nanoparticles from their ‘existing’ micro or macro‐scale counterparts. In doing so, the nanoscale ingredients would be considered to be a ‘new’ chemical or medicine under these frameworks, thereby triggering regulatory testing procedures. This approach would be a compromise between the present regime and the precautionary approach that is being introduced into the EU under REACH. However, it is recognised that this approach may not in itself address concerns over the appropriateness of the usual risk assessment methods for determining the potential risks of engineered nanoparticles. From a public health point of view, there is clearly a need for the international community to determine the appropriateness of testing regimes. Only when these critical knowledge gaps have been addressed will government, industry and scientists better appreciate the potential risks associated with nanoparticles and thereby act accordingly. As evidenced by the regulatory failures of thalidomide and asbestos, the only problem is that the costs associated with any delay may be too great.

Journal

Australian and New Zealand Journal of Public HealthWiley

Published: Aug 1, 2007

There are no references for this article.