Prepared concentration (ng/mL) Period after preparation (week, -80 oC) 0                           1                          2 freeze-resolution 2 times
2 2.0 2.2 2.3 2.0
40 40.0 41.4 41.0 40.0
Data is the average of 3 samples
Table 4: Stability of ameziniummetilsulfate (AM) in human blood plasma.