The formulation and oral application of therapeutic petides and proteins is still a challenge due to the proteolytic gastritic degradation and the poor adsorption mechanism out of the gut lumen. A particulate chitosan-based formulation of Interferon-beta-1b was prepared for the future oral administration using a spray drying process. The quantification of the biological activity of Interferon-beta-1b was carried out by means of an Anti Viral Assay (AVA) and an ELISA. The activity test showed no loss of the biological activity of Interferon after the manufacturing process.