Stability of Reconstituted Fibrinogen Concentrate in Hemostatic Function and Concentration

Canadian Armed Forces adopted fibrinogen concentrate (RiaSTAP) for hemostatic resuscitation in the far-forward combat setting, given its potential benefits of reducing blood loss, blood transfusion and mortality, and its long storage stability and high portability. The current guidance recommends that RiaSTAP should be administered within 8 hours after reconstitution when stored at room temperature. However, little information about its stability is available. There is also a need to investigate the stability and efficacy of RiaSTAP after reconstitution and exposure to extreme temperatures in which our forces may operate.

RiaSTAP was reconstituted as per manufacturer's instruction and stored at specific temperatures (-20°C, 4°C, 22°C, 35°C, 42°C, or 50°C) for up to 6 months. Reconstituted RiaSTAP was also oscillated on a rocker at 18 rpm under 22°C and 50°C. Its hemostatic function was measured using rotational thromboelastometry performed with RiaSTAP-spiked whole blood. Fibrinogen concentrations were measured by a commercial enzyme-linked immunosorbent assay (ELISA) kit. Gel electrophoresis was also conducted for initial and stored samples.

We found no change to the hemostatic function of reconstituted RiaSTAP after storage at -20°C for 6 months. At 4°C, no obvious changes to the hemostatic effect of reconstituted RiaSTAP relative to 0 hours were seen until 1,680 hours. At 22°C, a remarkable decrease began after storage for 168 hours. Storage at 35°C significantly decreased the hemostatic effect after 144 hours, while the storage at 42°C resulted in decreased hemostatic function after 72 hours. Finally, storage at 50°C for 8 hours resulted in complete loss of hemostatic function. Compared to the hemostatic activity, the fibrinogen concentration for reconstituted RiaSTAP showed less change over time. No apparent decline in fibrinogen concentration was seen after storage at -20°C for 6 months and at 4°C for 1,680 hours. At 22°C, there were no clear alterations until 792 hours. There was a decline in fibrinogen concentration at 35°C and 42°C after 672 and 600 hours of storage, respectively. At 50°C, little amount of fibrinogen was detected by ELISA at 8 hours. Similar changes in the hemostatic effect and fibrinogen concentration over time were observed under the rocking condition in comparison with the static condition at the same temperature. The gel electrophoresis confirmed fibrinogen degradation which increased with storage temperature and time.

The stability of reconstituted RiaSTAP decreases with increasing storage temperature. The hemostatic function deteriorated before fibrinogen concentration and integrity were significantly altered at all temperatures for the study period except at 50°C where there was a rapid decline in both hemostatic function and fibrinogen concentration. Sample oscillation did not significantly affect its stability. The shelf life of reconstituted RiaSTAP may, therefore, be recommended accordingly when stored at different temperatures and extended to 6 days at room temperature provided that sterility is maintained.