Cryoprotectants albumin

Freeze-drying is a relatively gentle way of removing water from proteins in solution. However, this process can promote the inactivation of some protein types and specific excipients (cryoprotectants) are usually added to the product in order to minimize such inactivation. Commonly used cryoprotectants include carbohydrates, such as glucose and sucrose proteins, such as human serum albumin and amino acids, such as lysine, arginine or glutamic acid. Alcohols/polyols have also found some application as cryoprotectants. 

Inactivation of enzymes during frozen storage was prevented by addition of 0.2 M sodium glutamate, 0.2 M (NH SO, or 0.1% egg albumin a synergistic cryoprotective effect was illustrated between sodium glutamate and albumin (122). 

As a stabilizing agent, albumin has been employed in protein formulations at concentrations as low as 0.003%, although concentrations of 1-5% are commonly used. Albumin has also been used as a cosolvend for parenteral drugs, as a cryoprotectant during lyophilization, and to prevent adsorption of other proteins to surfaces. 

What then is the effect of adding a macromolecular cryoprotectant to this system Such agents are effective at doses nearly stoichiometric with the catalase concentration and we interpret their effect as similar to that of increasing the enzyme concentration or to adding albumin to enzyme solutions, as is commonly done in biochemistry, to improve stability. The generic effect is to increase macromolecular interactions which retard solvent-solute inactivation. 

FITC-albumin FITC-albumin (MW about 70 kDa) intravenous injection (20 mg in 1 mL saline) 1 h survival Perfusion with 4 % PFA in PBS 24 h postfixation, cryoprotection in 30 % PBS sucrose, 30 pm coronal cryosections Increased BBB permeability Animal model of stroke [45]... 

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