Long-term stabilization of a new freeze-dried and albumin-free formulation of recombinant human interferon alpha 2b.

In this work, we evaluate the stability of a new freeze-dried and albumin-free formulation of recombinant human IFN alpha 2b (rhIFN-alpha2b) to be used in humans. The freeze-dried, albumin-free formulation was stored at the recommended temperature of 4 degrees C, and under accelerated storage conditions (28 degrees C). The stability of this product was also compared with the stability of a liquid albumin-free formulation of this cytokine. Finally, the stability of the freeze-dried albumin-free formulation was examined after reconstitution and storage at 4 degrees C and room temperature (28 degrees C) for 30 days. Samples were periodically subjected to biological activity assay (antiviral titration), reversed phase high-performance liquid chromatography (RP-HPLC), pyrogens, sterility and enzyme-linked immunosorbent assay (ELISA) testing, abnormal toxicity screening, organoleptic evaluation, and measurement of residual moisture and pH. Accelerated storage (28 degrees C) data for the freeze-dried albumin-free formulation showed biochemical stability of the active ingredient throughout the 6-month study, showing activity between 85 and 125% of its nominal value. RP-HPLC-determined purity showed that rhIFN-alpha2b remained above 95%. Additionally, the formulation was non-pyrogenic, non-toxic, sterile, and organoleptically acceptable. The real-time storage data confirmed the good biochemical long-term (30 months) stability of the freeze-dried formulation of this cytokine. Comparison with the liquid rhIFN-alpha2b albumin-free preparation showed that the freeze-dried albumin-free formulation maintained the stability of the active ingredient better than the liquid preparation. The formulation was also stable after reconstitution and storage at 4 degrees C and 28 degrees C, for 30 days.