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Chemical Reaction: Controlled Release

By: Steve Herman
Posted: March 5, 2008, from the March 2008 issue of GCI Magazine.

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There are significant delivery issues beyond treatment products. One of the great challenges of the fragrance industry is keeping scent on products incorporated in detergents and fabric softeners. Detergents are designed to wash out oily materials, and fragrances are oily materials.

Raw material suppliers, large fragrance companies and consumer goods companies all have technologies to deal with this situation, many of which are proprietary. Henkel uses a precursor based on salicic acid esters, which anchor fragrance molecules. The esters split through hydrolysis in the laundry process, releasing the fragrance.

MIT scientists have devised remotely controlled nanoparticles that, when pulsed with an electromagnetic field, release drugs. Nanoparticles carry two different drug loads. A remotely generated electromagnetic field releases the first active, and, later, a stronger pulse is used to release the second active. The second active is tethered by a DNA chain twice as long as the first, measured in the number of base pairs.

Green Methods

Green chemistry is being employed to develop revolutionary drug delivery methods that are more effective and less toxic. Chemists at The University of Nottingham (United Kingdom) are developing new methods for coating drugs in plastics, using methods that do not damage the latest generation of delicate biopharmaceutical drugs—which are at the cutting edge of modern medical treatment. Biodegradable polymers are made using supercritical carbon dioxide, eliminating the use of heat or harmful solvents. Using low temperature, delicate bioactive components, such as growth factors or proteins, can be mixed into the polymer without any loss of activity.

Green renewable resources are much in demand, and chicken feathers—typically a waste product—is an unusual and interesting example. The U.S. Department of Agriculture has awarded a four-year, $500,000 bio-based products grant to a University of Delaware research group working to develop advanced materials from chicken feathers and soybean oil. Work has been done using carbonized chicken feather fibers for hydrogen storage5. Hydrogen storage is not a cosmetic application, but this use demonstrates that unexpected sources will arise inevitably as green chemistry evolves and money is dedicated to research.