Nanotechnology Under the Microscope at FDA

The rapidly expanding use of nanotechnology in therapeutic formulations is driving FDA to better define the regulatory and analytical framework needed to assess and address the potential concerns involved.

At the AAPS National Biotech meeting in San Francisco on May 19, FDA Center for Drug Evaluation and Research (CDER) research chemist Katherine Tyner elucidated some of the reasons for regulator caution regarding nanoparticles.  “Nanoparticles have access to parts of the body other compounds do not,” she emphasized.  In addition, as particles get smaller their “surface properties dominate over bulk properties,” and surface reactivity increases.

Addressing emerging regulatory considerations for nanoparticle-containing therapeutics at another recent conference, CDER Office of Pharmaceutical Science Research Policy Associate Director Nakissa Sadrieh pointed to the analytical uncertainties on the horizon.  Sadrieh is chair of CDER’s Nanotechnology Working Group that is exploring what furthrer guidance and policy may be needed in the area.

“What I guess we don’t know right now is for the type of nanoparticle that we may be looking at,” for example, a dendrimer or nanotube, “what are going to be the important properties that we need to know [and] what is the best way for us to be able to evaluate those properties?” she said.  “If somebody could actually generate a table with the particle, the property and the methods that one would use to actually evaluate or characterize, that would be a great help to be able to adequately review these products and to know whether there are issues that we need to look at or not.”

Another area of concern, she added, is that the properties of nanoparticles may be “quite different from the normal properties that we look at right now for small molecules, [e.g.] electron microscopy methods. These are not methods that have been used in the past in manufacturing. So we need to find ways of being able to identify methods that are going to be adaptable to be able to actually develop drugs.”

Sadrieh explained that there is an agency-wide guidance that is being developed to cover the use of nanoscale materials in FDA-regulated products.

[Editor’s note:  The opportunities & challenges around nanotechnology development and regulation, including Sadrieh’s extended analysis are explored in the May 2010 issue of IPQ as part of an in-depth report on the changing CMC landscape.]