Opalescence appearance of antibody formulation correlation with molecular size or aggregation propensity
Objective:To explore the correlations between opalescence and molecular size,purity or aggregation tendency in the antibody formulation.Methods:Studied on the opalescence phenomena of various antibodies,in-cluding the influence of different concentrations,pH/buffer,excipients,as well as the influence of environmental factors such as temperature,light,freeze-thaw and agitation,and the correlations had been analyzed between o-palescence and molecular size,purity(aggregation),KD or Tagg.Results:The degree of antibody opalescence was positively correlated with the molecular size,the deepening of the opalescence indicated that the molecular size was increased and the more tendency of molecular aggregation.For example,the opalescence of C molecule obviously enhanced under high temperature,and the result of turbidity changed from 3.3 NTU to 13.6 NTU,the molecular size changed from 13.1 nm to 40.6 nm,and the KD changed from positive to negative.The Taggchanged from 59.6 ℃ to below 50 ℃.Conclusion:The opalescence can be affected by buffer system,pH,excipients and ambient temperature,the degree of opalescence increased,indicating the stability become worse and the molecules prone to aggregate.This study provides important reference for the analysis and evaluation of opalescence in the antibody formulation development.