Encapsulation Research

For almost five decades, SwRI has been a leader in microencapsulation research, development, and prototype production. Institute scientists have conducted numerous projects in the areas of agriculture, nutrition, flavor modification, environmental protection, heat transfer, adhesives, polymers, and pharmaceuticals. The Institute uses physical and chemical techniques to produce a variety of water soluble and insoluble coating materials that offer specialized release characteristics.

The Institute's work in microencapsulation technology has led to advances in many consumer products including detergents, bleaches, cosmetics, floor polishes, carpet cleaners, deodorants, toothpastes, and paints. Microcapsules have also been developed for the agricultural industry to provide sustained-release insecticides and herbicides as well as animal feed supplements. Examples include enzymes used in detergents to prevent harmful consumer exposure, bleach to prevent reaction with other components of cleaners, and deodorants to prevent skin irritation.

Institute scientists use a pilot-scale, spray dryer to encapsulate critical food ingredients that enhance qualities such as color, taste, odor, stability, and shelf life.

SwRI develops formulations and encapsulation processes for the food industry. Nutritional food supplements such as vitamins are encapsulated by manufacturers in order to inhibit the oxidation of these supplements. Carotenoids, which are natural antioxidants, are encapsulated to protect against degradation by light and oxygen. The encapsulated form can be added to foods or placed in two-part gelatin capsules as nutritional supplements.

SwRI scientists successfully developed an encapsulated agent for control of mites in honeybees. A patent has been issued for this product.

In the agricultural industry, microencapsulation is increasingly being used to target pest control agents to specific insects, protect animal feed additives from moisture or air, allow safer chemical handling for users, and provide controlled release of agents to increase effectiveness. SwRI staff members prepared large batches of an encapsulated growth regulator for controlling mosquito larvae using an interfacial polymerization process. The encapsulated form provides a convenient delivery system and a prolonged field life of the larvicide.

Industrial chemical encapsulation can provide improved product performance by separating reactive materials in products such as high-energy fuels, quick-reacting adhesives, and paints until the needed components are released. SwRI engineers encapsulated catalysts to provide one-part adhesives that are stable for prolonged periods. The Institute received a patent for the adhesive process technology, in which the curatives, or active materials, are coated with a temperature-sensitive shell. When heat is applied, the active material is released, and the adhesive cures. This eliminates the measuring and mixing steps used in two-part systems. In addition, it eliminates the need to refrigerate one-part adhesives.

SwRI engineers worked with the government and pharmaceutical and biotechnology companies to develop optimal dosage forms and formulations for controlled, sustained, or target delivery of pharmaceuticals. The Institute has identified polymer shell materials for oral, nasal, pulmonary, parenteral, subcutaneous, and suppository drug delivery routes. SwRI researchers have worked with resorbable polymers and used them to prepare nanospheres and microspheres for pharmaceuticals.

Multidisciplinary teams of engineers and scientists are identifying advanced biomaterials for implants and other demanding medical applications. SwRI engineers tested hydrogel polymers for cell entrapment and cell immobilization. In one key area of research, SwRI is collaborating with the Thomas E. Starzl Transplantation Institute in Pittsburgh, Pennsylvania, to immunoisolate the human pancreatic islet cell for the treatment of diabetes mellitus (Type I). In vivo tests have shown excellent biocompatibility in nonimmunosuppressed rats. Further work is needed to optimize the coatings and demonstrate blood sugar level control. If this technology proves successful, insulin-dependent patients would need only a single injection of the encapsulated cells every few years instead of more frequent insulin injections. Theoretically, consistent blood sugar levels could be achieved with this technology and the side effects of diabetes, such as circulatory problems that can lead to amputations, would be reduced.

Beneficial micro-organisms were encapsulated to protect them against moisture during animal feed processing. A patent has been issued for the production process and the composition of the product. A scale-up of the rotating disk process was provided to the client for production of the encapsulated bacteria. The encapsulation protects the bacteria from moisture to ensure a longer shelf life. Once ingested by animals, the coating dissolves and the bacteria supplements the animal's normal digestive functions.

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