Microsphere formulation is an extremely complex, multi-step workflow. First, the microspheres must be synthesized and then harvested. Polymeric microspheres–one of the preferred drug delivery vehicles for novel pharmaceutical–are typically derived from coacervation, evaporation, or spray drying, before being refined via de-watering, washing, drying, blending, and–in many cases–freeze-drying.
Freeze-drying is carried out by freezing the microspheres then applying an ultra-low vacuum and then increasing the temperature. Microspheres are freeze-dried because they become a flexible and porous solid once they have undergone the process. Additionally, they are dust free, have outstanding flow properties and are homogenous after being freeze-dried.
The freeze-drying method is becoming more widespread in pharmaceutical manufacturing because of its benefits for biopharmaceutical molecules and compounds with poor solubility. There could also be stability problems in the microspheres that can be corrected by freeze-drying. Additionally, all-in-one solutions that combine all preparation stages, from classification to recovery, make freeze-drying a more commercially viable option.