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Skin Care Thinks Small to Deliver Big

By: Leslie Benson
Posted: August 5, 2008, from the August 2008 issue of GCI Magazine.
An array of polymer microneedles 1,000 microns tall

Mark Prausnitz of Georgia Tech’s school of chemical and biomolecular engineering, one of the professors leading a U.S. team in finding a new mass delivery method for the flu vaccine, holds an array of polymer microneedles 1,000 microns tall. This photo, taken by Gary Meek and duplicated from the cover, is used with permission from Georgia Tech.

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But nanotechnology isn’t the only hot button spurring R&D formulators to action.

Emulsions—droplet-sized semi-solid liquids that topically deliver products to the skin, during which active ingredients can penetrate the top layers for their desired effect—are growing in sophistication.2 Select body lotions in P&G’s Olay line, for example, utilize mineral spheres to deliver ingredients.

According to P&G Beauty’s Mary Johnson, principal scientist, and Eric Admiraal, Olay brand manager, P&G Beauty first identifies a skin care active by in vitro methods and then designs a delivery system for in vivo testing to complement it. “We have also carefully designed our products to prevent interactions that could limit delivery of actives to skin. For example, we avoid product components that could complex with an active, thus impeding skin penetration,” say Johnson and Admiraal. “In addition, solvent types and levels are selected to maximize the partitioning of the active out the solvent and into the skin.”

Denise Elias-Costrini, global marketing manager of the Amerchol Corporation, a subsidiary of The Dow Chemical Company, says Amerchol conducted lab evaluations with actives such as vitamins A and C to validate the benefits it promotes for its new SatinFX delivery system, which the company launched at In-Cosmetics earlier this year. This encapsulation technology stabilizes hydrophobic and hydrophilic actives over time, preventing oxidation and discoloration of the finished formulation, she says. By shaking the system, it forms multilayer vesicles that encapsulate an active, improving its stability and efficacy. The vesicles break, says Elias-Costrini, when they are rubbed on the skin. “This also allows the encapsulation of ‘incompatible’ ingredients such as dihydroxyacetone (DHA) and amino acids, which can be used to create a sunless tanning product that also provides antiaging benefits,” she adds.

Croda Inc. also released two new advanced delivery technologies. Crodafos CES slows down the water evaporation of an emulsion on the skin, and the lipid and water-soluble Arlasolve DMI-PC, derived from corn syrup, is effective in the delivery of difficult-to-dissolve functional materials, according to Mark Chandler, technical manager of Croda Inc.’s skin care innovations lab. However, Chandler says that even with measurable clinical testing taking place, challenges abound when working with skin care delivery systems. “There are no one-size-fits-all systems. What worked for the previous material may halt delivery of the next material of focus,” he says. “The formulator must be willing to work with unfamiliar emulsion systems and delivery vehicles to obtain success. In the process, though, the formulator may not only build a more effective product but also may design one that has differentiated aesthetics.”