Macromolecules in polysorbate 80 for injection: an important cause of anaphylactoid reactions

Polysorbate 80 for injection (TW80) is a common excipient used for injection whose macromolecular impurities, including those that cause anaphylactoid reactions, are frequently ignored. The main aim of this study was to prove that the macromolecular impurities in the excipient are an important cause of anaphylactoid reactions. Component A (containing macromolecules > 100 kDa), Component B (containing macromolecules from 10 to 100 kDa), and Component C (containing substances < 10 kDa) were prepaired from the original TW80 using ultrafilters. The original TW80 contained numerous substances with molecular weights > 10kD. The original TW80 and Components A and B caused strong anaphylactoid reactions in both guinea pigs and rabbits by intravenous administration. Moreover, the original TW80 and Components A and B even caused strong passive cutaneous anaphylactoid (PCA) reactions and pulmonary capillary permeability. The PCA reaction and increased permeability were partly prevented by cromolyn sodium. Additionally, the original TW80 and Components A and B caused vasodilation and severe hemolysis in vitro. The anaphylactoid reactions were associated with histamine release but not with mast cell degranulation. Nevertheless, Component C almost caused no anaphylactoid reactions or hemolysis and was weaker in the few reactions that ocurred. Taken together, these results suggest that macromolecular substances are one of the main risk factors responsible for anaphylactoid reactions and hemolysis caused by TW80.