Microsphere formulation process scale-up

Camille Flores looks at technology that is changing the microsphere drug formulation process for the global pharmaceutical industry.

Drug manufacturers have used the commonly known method of sieving to classify the microspheres, facing difficulties with mesh blocking, lengthy drying and challenging SIP. The Microsphere Refiner technology was launched combining filtration, cake washing, classification and drying, all in one step, with sterile product recovery.

Microsphere particles work as miniature time release capsules made of biodegradable polymer and carrying the API of parental drugs. Microspheres are small spherical particles, typically from 5µm up to 150µm.

Microspheres are created from various micro encapsulation processes (single or double emulsion, droplet formation ...). At the end of this upstream stage, microspheres of random sizes are suspended in a large volume of liquid which needs to be processed. The downstream stage consists in the microspheres being classified by size, over and under size particles need to be removed to obtain the micron size range desired. The control of particle size distribution is critical during the formulation as it affects the time release effect of the micro capsules once injected in the patient's body. The microspheres are then washed, filtered and dried to be recovered in a sterile manner.

To perform the downstream stage, the Microsphere Scalping and Refiner have been designed and developed with steam-in-place and full drainability capabilities, and are both tiltable to accommodate a sterile discharge.

Some processes require a first scalping pre-filtration step in order to remove and recover all the oversized microspheres. Then with the Microsphere Refiner undersize particles are eliminated and the final product is washed, filtered, dried and recovered while maintaining the sterility envelope.

Traditionally sieving operation is achieved on non-sterile laboratory scale for microsphere drugs. But when sterile large scale production is needed, manufacturers are facing issues with blockage, sterility and poor product recovery.

Process scale up from R&D to industrial production is a common conundrum in the industry; therefore similar Microsphere Scalping and Refiner technologies have been used to perform the same method from lab to large scale manufacturing.

Small scale feasibility tests can also be carried out with small scale glass filter dryers (GFD) to filtrate and dry up to 50grams of cake, followed by the R&D Microsphere Scalping and Refiner classifying and drying up to 2kgs with sterile discharge. Then industrial formulation of microspheres is performed using advanced sterile filter dryer technology.

For more information at www.scientistlive.com/eurolab

Camille Flores is Business Development Manager, Powder Systems Limited (PSL), Liverpool, UK. www.powdersystems.com

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