Formulation

Crystallization offers a traditional and inexpensive method for specific protein purification and formulation. In the simplest case, impure protein solution is only pre-precipitated or diafiltrated and concentrated before crystallizing reagent addition.

Industrial process development includes studies for solubility (phase) diagrams, yield, crystal harvesting techniques, centrifugation, filtration and final formulation.

The pure crystals are a very good starting material for various protein products. Possible formulation forms for crystallized proteins are: a suspension in which solid crystals are in the mother liquor or other formulation solution; a liquid of dissolved crystals; or freeze-dried crystals. One possibility is to use the crystals as insoluble cross-linked catalysts in organic solvents.

Because crystals are the most concentrated form of protein, it is possible to produce highly concentrated final formulations by crystallization. Crystallization also offers a method for the control of particle size. Small crystals with good aerodynamic properties have potential for example for pulmonary protein drug delivery.