DESIGN AND APPLICATION OF A LOW-TEMPERATURE PELTIER-COOLING MICROSCOPE STAGE

A light microscopy system has been designed for freezing and lyophiliz ation studies of protein pharmaceuticals. The system consists of a cas cade of four Peltier thermoelectric modules in the lyophilization cell to freeze samples to -60 degrees C, controllers to regulate temperatu re and pressure conditions, and a video camera to record the events un der study. Specific demonstration of the system was conducted using re combinant CD4-IgG and human growth hormone (hGH) as model proteins. Ob servations of recrystallization during warming of frozen CD4-IgG solut ion and lyophilization of hGH solution are discussed. These examples d emonstrate that the system is a useful tool for the fundamental unders tanding of freezing and lyophilization of protein pharmaceuticals.