Table 4: Stability of PD in rat plasma ( at each level).

ConditionsTheoretical concentration
(ng/mL)
Final concentration
(ng/mL)
RE (%)CV (%)

Three freeze/thaw cycles
(−70°C)
150149.80.14.2
10001005.30.53.7
80007956.8−0.53.2

Bench top stability
(room temp., 24 h)
150147.9−1.47.0
10001053.55.45.2
80008180.92.31.8

Postpreparative stability
(4°C, 24 h)
150147.0−2.06.2
1000927.1−7.31.1
80007479.3−6.51.3

Long term stability
(−70°C, 1 week)
150148.4−1.15.5
1000973.9−2.63.1
80007425.3−7.21.9

Long term stability
(−70°C, 2 weeks)
150152.21.53.7
1000993.3−0.76.1
80007477.6−6.53.6

CV: coefficient of variation; RE: relative error.