Author Wields Nano-Sword to Strike Blow for New Nanotech Definition

When the FDA issued new draft guidance last month on developing drug products containing nanomaterials—minuscule substances measured in billionths of meters—it reiterated it hasn’t adopted a definition of that term or similar ones like “nanotechnology.”

Nanomedicine expert Raj Bawa says the FDA and other federal agencies should eschew bright-line size- or dimension-based definitions, such a National Nanotechnology Initiative one with a cutoff of below 100 nanometers. (A sheet of newspaper is about 100,000 nanometers thick, NNI says.) Although the FDA hasn’t formally adopted that limit, it uses it as a measuring stick.

Bawa, who co-edited the Handbook of Clinical Nanomedicine: Law, Business, Regulation, Safety, and Risk, argues in his chapter on “FDA and Nano” a one-size-fits-all definition doesn’t work. The 100-nanometer limit is meaningless to drug companies when the benefit of nanomaterials (such as improved bioavailability, lower dose, or enhanced solubility) may be achieved at a greater size, he writes. There also are numerous FDA-approved nanopharmaceuticals on the market exceeding the 100-nanomter threshold, Bawa says.

“Compounding this confusion,” Bawa writes, “is the fact that nanotechnology is nothing new and has been around for hundreds, possibly thousands, of years.”

Bawa cites the Damascus Sword, which legend says slices a falling silk scarf in half. Researchers discovered that nanowires and carbon nanotubes were embedded in its blades. The original method of producing the steel, which emerged as early as the 3rd century, was lost in the late 1700s.

Gold and silver nanoparticles were embedded in glass going back to the 4th century, Bawa adds, the most prominent example being the Lycurgus Cup, which changes color depending on the viewing angle—a feature scientists didn’t understand when the British Museum first acquired it.

Like Bawa, presumably the ancients didn’t care about a nanometer threshold, either.

Read my story on the FDA draft guidance here.

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