Lead production during Depression

In addition to the additives used in a formulation to help stabilize the protein to freezing, the residual moisture content of the lyophilized powder needs to be considered. Not only is moisture capable of affecting the physicochemical stability of the protein itself, equally important is the ability of moisture to affect the Tg of the formulation. Water acts as a plasticizer and depresses the Tg of amorphous solids [124,137,138]. During primary drying, as water is gradually removed from the product, the Tg increases accordingly. The duration and temperature of the secondary drying step of the lyophilization process determines how much moisture remains bound to the powder. Usually lower residual moisture in the finished biopharmaceutical product leads to enhanced stability. Typically, moisture content in lyophilized formulations should not exceed 2% [139]. The optimal moisture level for maximum stability of a particular product must be demonstrated on a case-by-case basis. 

Gelman et al. (1978) found that the interaction between lead and phenylhydrazine produced an additive effect in the acute hemolytic phase of anemia and a probable synergistic effect during the compensatory phase of anemia in rabbits. The mechanism postulated for anemic interaction appears to be primarily related to depressed bone marrow production of erythrocytes rather than to increased hemolysis. 

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