The use of nanoparticles as sun-screening agents has been widely discussed and thoroughly documented. “The nanoparticles in sunscreens, titanium dioxide and zinc oxide are established, efficacious sunscreen filters that have been on the market for decades,” according to The Cosmetic, Toiletry, and Fragrance Association (CTFA) in a press release1 announcing the association’s 2006 report on nanotechnology in personal care products.
Less well-known is the role of these very small particles as delivery vehicles. They are, however, increasingly of interest to drug companies. A search at www.uspto.gov for the terms nanoparticle and delivery in abstracts finds only two issued patents since 1976, but it finds 28 published applications since 2001. Almost exclusively, these patents are aimed at the pharmaceutical industry. Nevertheless, the same Web site holds several patents of interest to the personal care industry.
“Nanoparticle ingredients in personal care products sit on top of the skin, are used in small amounts and are not absorbed into the body,” said John Bailey, PhD, in the CTFA press release. Bailey is executive vice president for science at CTFA and a former official at the US Food and Drug Administration. Indeed, the two patents with personal care implications discussed in this column do make use of nanoparticle technology for controlled delivery of cosmetic agents on the skin surface.