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. 2016 Nov 16;11(11):e0164692. doi: 10.1371/journal.pone.0164692

Fig 2. Stability of Freeze-dried Influenza Vaccine Formulations (Round 1) at 37°C (A) and 45°C (B).

Fig 2

Formulations were prepared with concentrated bulk H1N1 subunit vaccine (H1N1 California/07/2009 X179A). In addition to the stabilizers shown in the figure, all formulations contain 45 μg HA/mL, 20 mM phosphate buffer, 0.09% polysorbate 80 and 14 mM NaCl. The formulations were freeze-dried as described in Materials and Methods and stored at 37°C (A, left) and 45°C (B, right). The HA titers were measured by SRID up to three months. For screening, one dilution for each formulation was tested by SRID in triplicate. The data were presented as percentage recovery relative to the mean HA titer after formulation preparation but before freeze drying (Pre-lyo) ± standard deviation of each triplicate. Abbreviations: SRID, single radial immunodiffusion; HA, hemagglutinin.