Some factors affecting the stability of interferon alpha 2b in solution

In this paper we evaluated the influence of the protein concentration and a formulation vehicle on the stability of recombinant human Interferon alpha 2b (rhIFN-α2b) in solution. The effect of the protein content (from 1 to 100 MIU/ml) at 37 °C, showed that higher concentration of this cytokine protected against the loss of bioactivity (antiviral titration) better than the lower concentrations. In contrast, rhIFN-α2b at 50 and 100 MIU/ml decreased the SDS/PAGE- and RP-HPLC-determined purity faster than samples at 1 or 10 MIU/ml. According to these results, 10 MIU/ml rhIFN-α2b was the best choice to evaluate the influence of a formulation on the stability of this cytokine. Taking this into consideration, we studied the stability of a liquid and albumin-free formulation of this protein at the recommended storage temperature (5 ± 3 °C) and under accelerated conditions (28 ± 2 °C). Accelerated storage results showed an acceptable biochemical stability of the active ingredient throughout 2 months. Real-time storage data confirmed the good biochemical stability of this formulation for 30 months.