Nanotechnology for Enhanced Control

Often, cosmetics and fragrances produce immediate, desired results, but quickly fade as the day wears on. Product developers can maintain longer-lasting effects with the use of a “controlled delivery” system, defined as a system with a predictable rate of active ingredient delivery to the skin. These active ingredients include fragrances, flavors or colors.

Recently, scientists have tapped into nanotechnology to enhance controlled delivery systems in the personal care arena. Nanotechnology is the ability to manipulate and manufacture product components less than 100 nanometers (nm) in their greatest dimension.

Reducing an ingredient down to nanoparticle size greatly alters the active ingredient’s physical/chemical attributes. It yields consumers’ desired effects, but may also enhance or reduce skin penetration, depending on the specific alterations. Titanium dioxide or zinc oxide nanoparticles recently debuted in sunscreens, as they are colorless and deflect ultraviolet (UV) light better than larger particles. Research has found punching holes into titanium oxide nanorods increases their ability to absorb UVA and B solar radiation by 25 percent, which in turn enhances UVA radiation protection. Oral and topical toxicity data indicate these nanoparticles have low systemic toxicity and do not adversely affect skin.

Other nanospheres can protect color-treated hair from oxidation and fading to further maintain color and brightness. Nanogel particle systems, with particles as large as 200 nm wide and derived from a biocompatible polymer, incorporate active ingredients on their surface and enable slow release.

Salvona Technologies developed a delivery system using hydrophobic nanospheres encapsulated in moisture-sensitive microspheres. When exposed to moisture, the ingredients inside disperse, prolonging release of the active ingredients from the nanospheres.

Other nanocarriers claim to encapsulate and transport vitamin E deeper into the skin. However, transdermal delivery research suggests nano-sized particles may penetrate the stratum corneum of human skin, but not living skin layers.

There is some concern about the long-term safety of this relatively new technology. Research by Sally Tinkle, Ph.D., assistant to the deputy director of the National Institute of Environmental Health Sciences, indicates different types of nanoparticles may be able to slip through the skin’s stratum corneum, potentially entering the bloodstream or interacting with the immune system. FDA advises caution when addressing topical exposure to nanoparticles that may penetrate the skin or have potentially toxic components. Therefore, nanoparticles warrant case-by-case safety evaluations prior to human use.

Ray A. Matulka, Ph.D., is a senior toxicologist at Burdock Group (www.BurdockGroup.com), a provider of ingredient-safety solutions to the food/beverage, personal care and dietary supplement industries, including claim substantiation, clinical trials and safety assessments.