Chemical and physical stability of chimeric L6, a mouse-human monoclonal antibody

Chimeric L6 is a mouse-human monoclonal antibody specific for tumor cell-associated antigens. The factors affecting the physical and chemical stability of chimeric L6 were assessed at elevated temperatures (30-60 degrees C) and by multiple freezing and thawing. Three routes of degradation were observed: chemical degradation to smaller molecular weight species, irreversible aggregation, and formation of a reversible dimer. The specific pathway depended on the stress condition applied and the pH, with maximal overall stability to both thermal stress and multiple freezing/thawing observed at about pH 5.5. Other factors including antibody concentration, buffer concentration, NaCl concentration, and agitation had minimal influence on the stability. Commonly used sugars, polyhydric alcohols, and amino acids effectively prevented freeze/thaw-induced aggregation.