In vitro stability studies of a Factor IX concentrate (Bebulin).

Factor IX: C activity decay was studied in lyophilized concentrates (Bebulin, IMMUNO) stored at room temperature and in reconstituted preparations frozen and stored at -20 degrees C. A very slight, practically identical, decay of Factor IX: C was found in lyophilized concentrates kept at room temperature, in reconstituted lyophilized concentrates frozen and stored at -20 degrees C and lyophilized concentrates kept at +4 degrees C. At the end of the experiment, which was 4-5 months after the expiration date of the product, a 15-30% decay of Factor IX: C could be found in the concentrates with respect to initial levels.