Microencapsulation and Controlled Release

For more than 50 years, the Institute has been an industry-recognized leader in the field of microencapsulation research. This year the Institute conducted more than 75 microencapsulation projects for companies ranging from small start-up firms to global conglomerates in such markets as functional foods, pharmaceuticals, consumer products, personal care, industrial chemicals, environmental, agriculture, and biotechnology. In the coming year, SwRI will address encapsulation and controlled-release programs using technologies such as radiation-induced polymerization, sol-gel processing, and nanotechnology.

In today's consumer-oriented market, significant emphasis has been placed on developing foods that are more flavorful as well as nutritious. SwRI has assisted numerous food companies in encapsulating ingredients with innovative, food-approved coating systems. In an on-going research project for Ocean Nutrition Canada, SwRI researchers developed a novel continuous emulsion quenching technique to microencapsulate fish oil. Clinical evidence shows that fish oils, which contain unsaturated omega-3 fatty acids, improve heart conditions and reduce the rate of heart attacks, myocardial infarction, and atherosclerosis. Microencapsulated ingredients can mask tastes, improve preservation, lengthen shelf-life, and provide higher nutritional value when incorporated in frozen foods, convenience foods, sauces, candies, nutritional bars, and cereal-based products.

Working with Champion Nutrition, SwRI performed research that enabled that company to develop a proprietary microencapsulation process for coating vitamins, minerals, herbal extracts, and many other nutraceuticals used in their powdered sports energy drinks, protein powders, and nutritional bars. The results of the project will reduce production costs by changing from a time-consuming batch process to an extremely efficient continuous encapsulation technique and by increasing taste-masking efficiency of shell formulations, reducing the amount of coating needed to apply.

SwRI researchers are developing microencapsulated functional ingredients for foods to provide health benefits to consumers, thereby eliminating the need for supplements.

SwRI has been actively involved in developing encapsulated products such as vitamins, minerals, nutrients, dietary fibers, aromas, flavors, and colors to further enhance the properties of foods. Microencapsulation of some ingredients can reduce off-flavors, time release nutrients, enhance flavor stability, and release colors on demand.

The Institute assisted FRx, a small firm founded by faculty at Clemson University, in developing new technology to remediate chlorinated organic ground water contaminants. Remediation of environmental toxins poses several technical challenges, including minimizing the amount of active agents required, targeting delivery of active agents to contaminated sites, mitigating unwanted remediation by-products, and examining the long-term effectiveness of active agents at a contaminated site. SwRI worked closely with the client to develop a microencapsulated, active agent to solve this problem. Preliminary laboratory results are encouraging, and SwRI recently completed additional microcapsule shell development work to further improve product performance. The client will begin field testing in 2001.

In coordination with the Centers for Disease Control, SwRI is funding an internal research project to produce targeted microparticles for the oral delivery of new peptide and protein drugs. These drugs are susceptible to acid degradation in the stomach, along with associated absorption problems, and require special formulation. The rabies antigen is being used as a model drug to prove the concept, as well as to provide a safe and convenient delivery method to control rabies in wild animals.

Pharmaceutical companies contract the Institute to develop and evaluate new shell materials for coating active ingredients to control release, improve stability, and mask taste and odor. Staff also assist with product development by evaluating the effects of coating techniques, shell molecular weight, and microsphere size on the drug release profile. Mallinckrodt, Inc. contracted the Institute to microencapsulate a water-soluble drug using various coating techniques to control the release of the product. Scientists are investigating the effects of the microencapsulation method and shell material formulation of the drug release profile.

The Institute continues to expand its microencapsulation work globally. International clients include the University of Western Sydney in Richmond, Australia; Gurit-Essex in Freienbach, Switzerland; and others. SwRI researchers designed and fabricated a prototype encapsulation unit to help the University of Western Sydney prepare smaller capsules using their current formulation. For Gurit-Essex, SwRI performed research and development in the encapsulation of polymer curatives.

Since 1993, SwRI has produced ALTOSID® for Wellmark International. This microencapsulated mosquito larvicide has been used in the United States to reduce mosquito infestations by preventing immature mosquito larvae from becoming disease-spreading adults. The active ingredient, methoprene, is an insect growth regulator that interferes with normal mosquito development. This regulator prevents mosquito larvae from maturing into breeding, biting adults. The larvae, rendered harmless, maintain the food chain and the relationship between the larvae and their natural predators. ALTOSID® Liquid Larvicide (SR-5) and ALTOSID® Liquid Larvicide Concentrate (SR-20) control mosquito populations in a range of habitats and application areas, including temporary or floodwater breeding sites and irrigated cropland. Methoprene is highly target-specific and does not affect fish, waterfowl, mammals, or beneficial predatory insects. This year, Wellmark extended the production agreement with SwRI.

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