The FDA recently issued a draft Guidance titled, "Safety of
Nanomaterials in Cosmetic Products" which addresses FDA's
current thinking on how to assess the safety of using nanomaterials
in cosmetic products. Somewhat ominously, the first paragraph of
the Background section states that "[nano]materials can have
chemical, physical, and biological properties that differ from
those of their larger counterparts. Importantly, properties of a
material might change in ways that could affect the performance,
quality, safety, and/or effectiveness, if applicable, of a product
that incorporates that specific nanomaterial." In light of
that introduction, it is not surprising that the Guidance
recommends extensive safety testing of cosmetics that incorporate
nanomaterials before those products are put on the market, even
though only color additives are subject to FDA's premarket
approval.
The draft Guidance divides the safety assessment into two broad
categories, nanomaterial characterization and toxicology
considerations. Under nanomaterial characterization, the draft
Guidance states that the characterization should include the
nanomaterial name, the Chemical Abstracts Service (CAS) number, the
structural formula, the elemental composition including the degree
of purity and any known impurities or additives. For
physicochemical properties, the characterization should further
includemeasurement of particle size and distribution;
aggregation and agglomeration characteristics; surface chemistry
including zeta potential/surface charge, surface coating,
functionalization, and catalytic activity; morphology including
shape, surface area, surface topology, and crystallinity;
solubility, density, stability, and porosity.
For impurities, the draft Guidance notes that any change in the
manufacturing process may result in additional impurities and that
the quantity and quality of any impurities should be considered in
the safety assessment.
As to toxicology, in summary the draft Guidance states that safety
testing should consider "each ingredient's chemical
structure and physicochemical properties, purity/impurities,
agglomeration and size distribution, stability, conditions of
exposure, uptake and absorption, bioavailability, toxicity, and any
other qualities that may affect the safety of the product according
to its intended use." Further, the draft Guidance states that
both short-term and long-term toxicity of nanomaterials must be
considered.
Other factors addressed in connection with toxicology include
routes of exposure, uptake and absorption, and testing methods. The
draft Guidance notes that while most cosmetics are applied to the
skin, some are applied in areas where there is a risk of exposure
through the mouth or nose, so safety must be assessed in that
context. With respect to uptake and absorption, the draft Guidance
states that the reduced particle size of nanomaterials may result
in increased absorption, which must thus be considered, and that
tests should be conducted on both intact and damaged skin. Because
of the different routes of exposure and potential for increased
absorption, the draft Guidance recommends that safety assessments
include the issues of toxicokinetics and toxicodynamics. The draft
Guidance discusses several testing methods that will have to be
considered depending on the type of product and other
factors.
As with the simultaneously issued draft Guidance covering the use
of nanotechnology in foods and food packaging, the draft Guidance
on cosmetics states that because of the different properties of
nanomaterials, it may be necessary to develop and validate new test
methods to ensure safety of the products. FDA recommends that
manufacturers request meetings to discuss "to discuss the test
methods and data needed to substantiate the product's safety,
including short-term toxicity and other long-term toxicity data as
appropriate."
Cosmetics have traditionally received the least amount of
regulatory attention from FDA, and this relative neglect has been
justified by a relatively low number of safety issues.
Manufacturers of cosmetics considering the addition of
nanomaterials to their products, however, should consider
increasing their research & development and regulatory budgets
to account for the validation of safety tests and safety
assessments that FDA will apparently recommend, or to evaluate
whether the addition of the nanomaterials to their products will
provide sufficient incremental benefit to their products and sales
to justify the costs of the safety assessments.
As always, it is important to recall that FDA Guidance documents do
not have the force of law, but rather simply represent the
FDA's current thinking on a topic.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.