» Rabies Immune Globulin conforms to the regulations of the FDA concerning biologics (see Biologics 1041). It is a sterile, nonpyrogenic, slightly opalescent solution consisting of globulins derived from blood plasma or serum that has been tested for the absence of hepatitis B surface antigen, derived from selected adult human donors who have been immunized with rabies vaccine and have developed high titers of rabies antibody. It has a potency such that when labeled as 150 International Units (IU) per mL, it has a geometric mean lower limit (95% confidence) potency value of not less than 110 IU per mL, and proportionate lower limit potency values for other labeled potencies, based on the U.S. Standard Rabies Immune Globulin and using the CVS Virus challenge, by neutralization test in mice or tissue culture. It contains not less than 10 g and not more than 18 g of protein per 100 mL, of which not less than 80 percent is monomeric immunoglobulin G, having a sedimentation coefficient in the range of 6.0 to 7.5S, with no fragments having a sedimentation coefficient less than 6S and no aggregates having a sedimentation coefficient greater than 12S. It contains 0.3 M glycine as a stabilizing agent, and it contains a suitable preservative. It has a pH between 6.4 and 7.2, measured in a solution diluted to contain 1 percent of protein with 0.15 M sodium chloride. It meets the requirements of the test for heat stability.