Figure 6: Analyses of IFN variants. The variants (IFN-α 2a) were prepared as described in [27] and (Diress et al. unpublished data). The variants included aggregated, deamidated or oxidized forms. The data showed that no significant loss of potency was observed with deamidated IFN while approximately 23% loss of potency was observed with the oxidized form; moreover, the aggregated form completely lost its bioactivity. Each sample was tested in triplicate and potency was determined by comparison to the EDQM IFN-α 2a reference standard.