Effects of submicron particles on formation of micron-sized particles during long-term storage of an interferon-β-1a solution.

We present evidence that homogeneous submicron particles can influence the growth rate of larger particles upon long-term storage in a temperature-dependent manner. Interferon-beta-1a was thermally stressed at 50°C for 6 h and characterized using nanoparticle tracking analysis (NTA), microflow digital imaging (MFI), and circular dichroism (CD) spectroscopy. This study showed selective formation of submicron particles exhibiting a perturbed protein conformation.