Microencapsulation

For more than 50 years, Southwest Research Institute™ (SwRI®) has played a leading role in microencapsulation research and development and in prototype microcapsule production. Using their extensive expertise in technical fields such as chemistry, pharmaceutics, surface sciences, engineering, food and nutrition, and polymer science, Institute microencapsulation specialists solve product stability, release, and application problems in a wide range of industries. The Institute, an independent research and development organization, has conducted more than 800 microencapsulation research programs for its clients.

Founded in 1947 as an independent, nonprofit research and development organization, SwRI provides a significant research, engineering, and testing resource for industry, business, and government. The Institute uses a multidisciplinary, integrated approach to solving complex problems in science and applied technology.
 

The Institute utilizes rotating discs to encapsulate liquids and solids, using polymer solutions and hot melts. (Inset) Maintaining good laboratory and manufacturing practice standards (GLP and cGMP), SwRI assists clients with drug reformulation, formulation, and analytical testing using selected polymeric matrices for controlled, delayed, or targeted delivery.

SwRI’s Chemistry and Chemical Engineering Division, which conducts the comprehensive microencapsulation program, has achieved certification to ISO 9001:2000, ensuring compliance with stringent quality control procedures in development, production, and servicing. The Institute has recently completed a state-of-the-art 14,400-square foot facility that includes current Good Manufacturing Practices (cGMP) suites.

Microencapsulation Techniques

Institute staff members have many years of shell formulation experience using a broad range of hydrophilic and lipophilic shell materials such as proteins, hydrocolloids, gums, waxes, polymers, and resins. Engineers and scientists apply numerous physical and chemical encapsulation techniques in solving client problems. Some of the more commonly used techniques and the capsule size range are shown in the table on the right.
 

Encapsulated food additives provide taste masking and protection from other ingredients and oxygen.

Controlled Release Mechanisms

Institute scientists develop microcapsules that provide a variety of release mechanisms, including:

• Mechanical rupture
• Thermal release
• Permeation
• Dissolution
• Delayed and targeted release
• pH and osmotic release
• Photolytic release
• Biodegradation
• Triggered release

The Institute-developed centrifugal extrusion system can encapsulate liquids, gases, and slurries. The system can produce several million core-shell microcapsules per minute.

Applications

SwRI develops microencapsulation solutions for a wide range of applications, including:

• Food additives
• Nutraceutical and pharmaceutical products
• Personal care and consumer products
• Agrochemicals
• Industrial chemicals
• Adhesives and sealants
• Cosmetics

Consumer products improved by the use of encapsulation include paints, cosmetics, deodorants, detergents, toothpastes, and shampoos.

This brochure was published in May 2002. For more information on microencapsulation, contact Joe Persyn, Phone (210) 522-2691, Fax (210) 522-3649, James Oxley, Phone (210) 522-2913, Fax (210) 522-4565, Chemistry and Chemical Engineering Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Fax (210) 522-4632.

For more information on microencapsulation and controlled release, see our department web page at microencapsulation.swri.org.

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