Microspheres are small spherical particles, having a required size range (typically 5 up to 250 μm). These particles can be manufactured from various natural and synthetic materials such as polymer microspheres. New applications for microspheres are discovered every day. Powder Systems Ltd (PSL) has developed process solutions for drug delivery, as biodegradable polymer microspheres can work as miniature time release capsules for parenteral drugs. Along with these types of processes, other pharmaceutical and biotechnology requirements have evolved utilising microsphere technology.
Microsphere production is experiencing a fast growing demand due to its characteristics and applications. Blue chip pharmaceutical companies around the world are adopting this formulation method, usually developed by laboratory development contract organisations and research universities. The first applications for the pharmaceutical sector were developed 10 years ago, mainly in the US where, according to PSL, it was already a pioneering equipment manufacturer providing small-scale sterile systems specifically designed to suit the microsphere formulation.
Suspended microspheres obtained from various micro encapsulation processes require handling that differs from a typical filtration and drying operation. Following the synthesis stage, microspheres need to be washed, classified by size, filtered and then dried under appropriate conditions to gain the final free-flowing injectable or inhalation microsphere product. Microspheres are random in size and need to be filtered and classified into the micron size range desired before drying. PSL microsphere refiners have been designed to meet these criteria from washing to classifying and drying.
With PSL microsphere refiners’ reportedly unique design, utilising side and bottom filtration, size classification is achieved. Classification being the most difficult task associated with microsphere production. Typically with microsphere processes, large liquid volumes with a small ratio of suspended solids have to be handled, therefore some processes require a scalping pre-filtration step to reduce the liquid volume and eliminate the oversized microspheres. This is achieved with the PSL scalping filter prior to transfer into the microsphere refiner.
Most microsphere processes require sterility, PSL solutions have been designed with SIP and drainability capabilities. The discharge is part of the sterility envelope. The microsphere refiner is tiltable to accommodate a sterile discharge.
PSL has completed a number of worldwide projects using microsphere filtration solutions from laboratory-scale to commercial production. This complex process is now implemented more and more around the world by undisclosed pharmaceutical and biopharmaceutical companies.
Powder Systems Ltd, +44 151 448 7700, info@powdersystems.com, www.powdersystems.com.