Nanoparticles in cosmeceuticals need more research

Durham, N.C. - Nanoparticles can enter and penetrate the skin theoretically and could represent a new delivery system for cosmeceuticals. The nanoparticle products are still in the developmental stage, however, due to unknown risks and other obstacles, according to Zoe Diana Draelos, M.D., consulting professor, department of dermatology, Duke University School of Medicine, Durham, N.C.

“Nanoparticles are used in an effort to make sunscreens invisible on the skin. Also, cosmetics that are colored with nanoparticle pigments can offer interesting camouflaging opportunities,” Dr. Draelos says. There is still international concern over the adverse effects of using these particles, she adds.

Use in cosmeceuticals
Nanotechnology is a branch of engineering that has potential applications in medicine and dermatology. Nanotechnology applies the unique properties of matter on the nanoscale (1,000 nm and smaller) for the purposeful design of new materials.¹

Dermatology has been exploring the benefits of nanotechnology in cosmeceuticals, which are products that have both cosmetic and therapeutic benefit claims. Cosmeceuticals usually are not supported by double-blind controlled clinical trials, and they are not regulated by the Food and Drug Administration. Therefore, manufacturers do not need to provide evidence-based support of claims as they do with medications.

Nanotechnology applications have been used in sunscreens and are being developed for the maintenance of skin health, as well as for the diagnosis and management of skin disease.¹ According to a recent study³, a large number of patents have been issued for nanotechnology in the cosmetics arena as a means of enhancing topical delivery of a broad range of over-the-counter products.

“Nanoparticles are particles that have one dimension and that are smaller than 100 nm. Even though zero to 100 nm is very small, it is quite a range,” Dr. Draelos says.

Nanoparticles that are smaller than 10 nm, known as quantum dots, are being used in experiential imaging systems, but not in dermatology, she says.

While there are about 1,000 nanoparticle dermatology products on the market, there are some problems with the technology and delivery thus far.

“In order for a nanoparticle to penetrate the skin, it has to be smaller than 13 nm and usually products that are made to be invisible on the skin surface, such as sunscreens, would have to be between 35 to 75 nm,” Dr. Draelos says. “Yet these sunscreen products often don’t stay as an even emulsion, and that’s why even though people might apply a nanoparticle sunscreen, it still might look white on the skin because all the nanoparticles have stuck together.”

In most cases, when nanoparticles are placed in a bottle of sunscreen, the nanoparticles do not remain as single particles.

“Instead, they tend to aggregate agglomerate, or settle out and stick together in the bottle,” she says. “Therefore, with nanoparticle sunscreens when the particles come out of the bottle they are no longer nanoparticle size.”

Possibilities and delays
Nanoparticle cosmetics hold some interesting possibilities.

“Pigments can be made very, very small, and then they can be selectively absorbed on some wavelength, and by doing that they can provide camouflage to underlying skin without having the need for a thick cosmetic. Although that is a potential use, the cosmetics industry as a whole is concerned about nanoparticles because of the unknown side effects and or adverse reactions,” Dr. Draelos says.

As a result, cosmetic applications are in a holding pattern, according to Dr. Draelos.

“The cosmetics industry has had a volunteering hold on using nanoparticles until it can better understand what they do. There is controversy as to whether nanoparticles actually penetrate the skin or not,” she says.

Much of the original early research work with nanoparticles was conducted on porcine skin, which is more permeable to nanoparticles than human skin. Results differ based on the model that was used to investigate it, Dr. Draelos says.

Researchers are now looking at ways of developing products in which the nanoparticles would not stick together.

“One of the most interesting things they are doing is taking the nanoparticles and coating them with polymers, and that also decreases their penetration as well,” she says.

Research needed
Matter on the nanoscale has the potential for significant chemical volatility, which carries with it an increased risk of cellular and tissue damage.² The skin is the first point of contact for a whole host of nanomaterials, including cosmeceutical topical preparations, and little is known about the safety aspects of the nano-engineered materials that are being released in the environment, as well as those in consumer and healthcare products.³

Today, many countries are trying to get a better understanding of nanoparticles and its effects.

“In Sweden, companies cannot market any nanoparticles,” Dr. Draelos says. “In the EU, after 2012 manufacturers will have to put the word ‘nano’ in parentheses on any product that contains nanoparticles.”

One of the concerns regarding nanoparticles is their potential impact on the environment.

“For example, nanoparticles do have some antibacterial components, and they can be lethal to some forms of ocean life,” she says. “Overall, people are still in a fact-finding stage concerning nanoparticles.”

Disclosures: Dr. Draelos reports no relevant financial interests.

References:
1. Nasir A. Nanodermatology: a bright glimpse just beyond the horizon - part I. Skin Therapy Lett. 2010;15(8):1-4.
2. Nasir A. Nanodermatology: a glimpse of caution just beyond the horizon - part II. Skin Therapy Lett. 2010;15(9):4-7.
3. Nasir A, Friedman A. Nanotechnology and the nanodermatology society. J Drugs Dermatol. 2010;9(7):879-882.