PSL Develops Microsphere Refiner for Formulation of Microspheres

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PSL has developed a microsphere refiner for microsphere formulation, from small scale processes to commercial production.

PSL, a manufacturer of filtration, drying and complete containment solutions, announced that it has developed a microsphere refiner for microsphere formulation. There is a high demand for microsphere production within the pharmaceutical industry. Formulation methods are usually developed by laboratory development contract organisations and research universities. The PSL microsphere refiner offers unique filtration solutions for microsphere formulation, from small scale processes to commercial production.

Microspheres are small spherical particles, typically ranging from 5 microns up to 250 microns. The particles are manufactured from various natural and synthetic materials such as polymer microspheres. The biodegradable polymer microspheres can work as miniature time-release capsules for parenteral drugs.

Suspended microspheres obtained from various microencapsulation processes require unique handling that is different from a typical filtration and drying operation. After the synthesis stage, microspheres must be washed, classified by size, filtered and dried under appropriate conditions to gain the final free-flowing injectable or inhalation microsphere product. PSL microsphere refiners have been designed to meet these criteria from washing to classifying and drying. Size classification, considered the most difficult step in microspheres production, can be achieved with PSL’s unique design, which utilises side and bottom filtration.


Microsphere processes generally involve handling large liquid volumes with a small ratio of suspended solids. Some processes would therefore require a scalping prefiltration step to reduce the liquid volume and eliminate the oversized microspheres. This can achieved with the PSL scalping filter prior to transfer into the PSL microsphere refiner. PSL stated in its press release that several projects have been completed using the company’s microsphere filtration solutions from laboratory scale to commercial production.