Tag Archives: nanomaterial skin absorption state of the art of research

Danish evaluate research on absorption of nanomaterials through the skin

An Oct. 3, 2013 news item on Azonano announces a report produced by the Danish Environmental Protection Agency on the state of research into dermal absorption of nanomaterials  (Note: A link has been removed),

 A new report published by the Danish Environmental Protection Agency (EPA) provides a comprehensive evaluation of the knowledge base regarding the dermal absorption of nanomaterials.

The report is the final output of the project “Dermal absorption of Nanomaterials”, which forms part of the “Better Control of Nano” initiative 2012 – 2015 conducted by the Danish EPA with the aim of further clarifying possible risks to consumers and the environment from nanomaterials.

The overall objectives of the project – which was led by the Institute of Occupational Medicine (IOM) working with COWI A/S – were to:  i) gather and evaluate the existing knowledge concerning the dermal absorption of nanomaterials, ii) assess the need to generate new knowledge, and iii) develop recommendations for the most suitable skin models, measurement methods and relevant candidate nanomaterials for future experimental testing.

The report: Dermal Absorption of Nanomaterials Part of the ”Better control of nano” initiative 2012 – 2015 Environmental Project No. 1504, 2013 gives a good description of skin and a good technical overview of the literature and the state of the research which, for the interested reader, could supply the basis for a better understanding of how to read research papers on this topic.  The report does not offer consumer information about nano sunscreens, etc.

Here’ are some of the conclusions from the Executive Summary,

One of the key challenges in assessing the literature on the physicochemical properties influencing dermal penetration/absorption of nanomaterials is that it is difficult to draw conclusions due to either: i) limitations in the reporting of physicochemical data, and/or, ii) the alteration of multiple experimental parameters in a non-systematic way. The issue of a lack of information on nanoparticle physicochemical properties is common, yet the most challenging aspect is the alteration of multiple experimental parameters whereby multiple characteristics such as shape, charge, coating, size can all be changed. This means that little meaningful comparison of results can be made within a single experimental study, let alone between studies.

Despite such challenges, some key conclusions can be drawn. [emphasis mine] Whilst there are many conflicting results, on balance the literature seems to suggest that absorption of particles in the nano-range through the skin is possible although occurs to a very low degree and that the level of penetration, depending on chemistry and experimental conditions, may be greater than for larger particles. The role of size is considered a critical component of dermal absorption but this in itself does not seem to guarantee absorption or lack of as other properties can also influence dermal absorption markedly. In addition, particle size is not necessarily a constant parameter as agglomeration of particles can occur over time and also in relation to experimental conditions (e.g. presence of surfactants within particle vehicle formulation). However, whilst this issue of agglomeration has been suggested as being important (as well as an important experimental variable), agglomeration state is often not reported within studies.