Units for Microspheres and Microcapsules
Powders and Granules
Free-flowing powders and granulates are needed for a variety of industrial processes. These, however, do not always meet the exacting standards which modern manufacturing demands of them due to their varying grain size distribution and odd shapes.
Spray processes
These properties are detrimental to efficient processing and lead to agglomeration, inexact dosage, abrading with loss of material or low reproducibility of castings. Pharmaceutical applications require highly reproducible dosage and the controlled release of active agents and this can not be achieved with conventional powders and granulates.
The solution to these Problems
The use of small and perfectly round Microspheres with exactly the same size circumvents all of the disadvantages that are encountered while using powders and granulates. These Microspheres are free flowing and roll with practically no friction, that means there is no abrasion guaranteeing a dust free environment. Pharmaceuticals embedded in the Microsphere matrix are released continuously and at a constant rate.
Ultra Spherical Microspheres
Microspheres with a monodisperse grain size distribution and the smallest divergence are manufactured by BRACE:
- perfectly spherical Microspheres
- monodisperse grain size, narrow size distribution with diameters between 50µm and 5000µm
- non abrading therefore dust free
- free flowing, porous, large surface area, soft or rigid
- for embedding pharmaceuticals, bacteria, enzymes or other heterogeneous catalysts with or without coating
The BRACE-Process
A liquid is gently pumped through a vibrating nozzle system where upon exiting the fluid stream breaks up into uniform droplets. The surface tension of these droplets moulds them into perfect spheres in which gelation is induced during a short period of free fall. Solidification can be induced in a gaseous and/or liquid medium through cooling, drying or chemical reaction. There are no constraints on the type of liquid - i.e. molten material, solutions, dispersions, sols or suspensions can be used to manufacture perfectly spherical Microspheres.
Types of Production Facilities and Services
BRACE designs, constructs and installs Microsphere production units from the laboratory scale up to full size production plants. Throughput and exact price of the production units vary with the size of the Microspheres and the complexity involved in the solidification process. Laboratory units as the desktop unit Spherisator S or M are avilable for competetive prices. Pilot- and production unit with capacities from a few kg/h to over 10,000 L/h are available, too.
Additionally BRACE also stocks a series of standard Microspheres and is able to produce Microspheres according to customer specifications.
Processing Characteristics
A monodispersive grain size distribution can only be obtained with a constant laminar flow through the nozzle. Amplitude and frequency of the nozzle oscillation are held constant by a closed loop control circuit but both can be varied to a degree to influence the grain size. Both must be held constant during a production run. Microsphere production units have a minimal space requirement (15 to 40sq.feet), their energy consumption is very low and they are noiseless during operation. These units operate at atmospheric pressure or slightly above and can be designed to be explosion proof according to the GLP/ GMP guide lines. Microsphere production units from BRACE need practically no maintenance, therefor only a minimal staff is required. Units with fully automated controls and remote monitoring can be delivered as an option.
Types of Microspheres
There are very few restrictions on the types of Microspheres than can be produced. Through the right combination of liquid precursor, soldification process and subsequent treatments a wide variety of Microspheres can be produced.
Examples
- Dry metal oxide Microspheres produced on the basis of a sol (Al2O3, ZrO2, HfO2,
TiO2, CeO4, SiO2, and mixed oxides) can be used as highly sinteractive press-feed for the production of high-tech ceramics. Through calcining the pore size and surface area of the Microspheres can be tailored within the exacting specifications. These Microspheres make excellent catalyst carriers, homogenous catalysts or filtering materials. Unusually effective and abrasion resistant Microspheres for grinding other materials are made from sintered Al, Zr and Hf-oxides. - Microspheres produced from molten materials (inorganic, organic, alloys and polymers) can be used for dosing, proportioning, compounding, colouring and light stabilization. Microspheres with dissolved or embedded active agents, with or without coating, are used for numerous pharmaceutical and cosmetic products.
- Soluble chemical compounds can be incorporated into Microspheres by precipitation for use in agricultural, food, pharmaceutical and cosmetics industries.
- Suspensions are used to produce Microspheres with embedded enzymes or bacteria.
