Micro- encapsulation

Biodegradable particles for medicine and pharmacy

Microcapsules have been applied in medicine and pharmacy for a long time. They are used to protect from the environment or the environment is protected from the active agents. The active agent of the aspirin tablet e.g. is microencapsulated to protect the stomach. Various active agents (e.g. drugs against cancer) are coated to get a targeted release. By additional microencapsulation of small magnetic particles it is possible to target the drug in the body by applying a magnetic field. A further task of microencapsulation is controlled release of the microencapsulated active agents. Depot drugs are able to release the active agent under controlled rate over a long period.

Tailor-made foods

Microencapsulated sensitive food additives like essential amino- or fatty acids, vitamins, enzymes, mineral substances or flavours can be processed gently. We are using wall materials approved for food applications. Beyond that we also modify approved film forming auxiliaries, e.g. starches or dextranes. By applying microencapsulation technologies to food additives it is possible to

• Protect them against the environment
• Mask odour and/or flavours
• Get long-term stability
• Get controlled and/or delayed release
• Optimise dosage and mixing
• Prevent contaminations
• Reduce allergic reactions

Development of materials for "smart systems"

New applications of the microencapsulated additives as functional materials or "smart systems" were found in the recent past. Intelligent sealants contain spherules with a moisture soluble shell. Following shell dissolution the core material swells and reaches a multiple of the initial volume. Screws are immediately glued together during tightening if the threads are coated with glue containing microcapsules. Applying the microencapsulation technology it is possible to associate apparent contradictory properties in one material. After microencapsulation water-soluble fertilizers, insecticides or herbicides withstand even heavy rain and function over the complete season.

Possible application areas are:

• Plastics industry (incorporation of active agents or additives)
• Plating (incorporation of lubricants or corrosion inhibitors)
• Building industry (heat accumulators, pesticides)
• Painting industry (pigments, antifouling agents)
• Textile industry
• Print- and paper industry

Offer

The development of microcapsules and matrix particles based on synthetic or natural polymers is the main research field of the microencapsulation group. Polymers are tailored concerning the application purposes as well as the microencapsulation technologies. Know-how in the field of active agent microencapsulation is completed by the corresponding knowledge in chemistry, technology, processing and application of the polymers used as microcapsule or matrix particle wall material. We are offering feasibility studies including the whole profile of the requested application. Technical parameters like long-term stability, wall thickness, particle size and –distribution are optimised. We also provide support in scaling-up the developed/modified microencapsulation processes. Samples can be supplied up to kg-quantities.

Technical applications (e.g. plating, plastics industry, plastics processing)

Reactive microencapsulation technologies:

• Interface polycondensation
• Interface polyaddition

Wall materials, e.g. :

• Amino resins
• Polyureas

Core materials e.g.:

• Dyes
• Mineral oils
• Glue components
• Flame retardants
• Metall flakes
• Lubricants

Life science applications (e.g. medicine, pharmacy, cosmetics, foods)

Reactive and non-reactive microencapsulation technologies

• Solvent evaporation
• Spray drying
• Coacervation
• Interface polycondensation
• Dropping technologies

Wall materials

Synthetic polymers, e.g.:

• Amino resins
• Acrylates
• Polyurea
• Homo- and copolymers of lactic acid

Natural polymers, e.g.:

• Polysaccharides (alginates, chitosan, starch derivatives, gum Arabic)
• Cellulose derivatives
• Proteins (gelatine)

Core materials, e.g.:

• Peptides
• Perfume oils
• Zytostatica
• Steroids
• Pigments

Patents

Modified amino resin precondensates based on fatty acid substituted amine
R. Nastke, G. Rafler
DE19814880 (1998)

Solid matter micro-encapsulated by an aminoplast and method for producing the same
R. Nastke, G. Rafler
DE 10049777 (2000)

Discrete microcavity particles having a flexible wall structure
R. Nastke, G. Rafler
DE 10111094 (2001)

Microcomposites and a method for their preparation
M. Jobmann, J. D. Hoß, G. Rafler
DE 10231706 (2002)

Core/shell microcapsules obtained from a rubber-containing core and a shell from a first polymer and from a second different polymer useful for rubber vulcanisation
M. Jobmann, G. Rafler, I. Gross, J. Sagala
DE 10241942 (2002)

Micro-encapsulation of hydrophilic or water-sensitive solid particles, e.g. catalysts or other modifiers for use in paint, involves forming the capsule wall from amino resin precondensate in an aqueous-organic solvent mixture
R. Nastke, G. Rafler, W. Zinser, M. Hensel
DE 102004004107 (2004)

Microcapsule, useful to store latent heat in buildings and transports, comprises an inorganic salt, as core material
F. Börner, G. Rafler
DE 102005002169 (2005)

Microencapsulated rubber additives and method for the production thereof
M. Jobmann, G. Rafler, M. Hensel
DE 102005035388 (2005)

Thermally stable microparticles for plastic additives and process for their preparation
J. Lang, G. Rafler
10 2006 016 307.9-43 (2006)