Nominal concentration (ng/mL) Stability Mean ± S.D.a
n = 6 (ng/mL)
Precision b
(%)
Accuracy c
(%)
  40   0 h (for all) 39.05 ± 2.93 7.50 97.63
20 h (Auto-sampler) 37.33 ± 1.45 3.89 95.60
4 h ( bench top) 42.12 ± 1.56 3.71 107.85
3rd freeze-thaw 42.07 ± 2.25 5.34 107.73
15 day at -80ºC 42.27 ± 1.87 4.42 108.24
         
1600 0 h (for all) 1548.33 ± 43.09 2.78 96.77
20 h (Auto-sampler) 1620 ± 71.27 4.40 104.63
4 h ( bench top) 1546 ± 75.37 4.87 99.85
3rd freeze-thaw 1544 ± 83.55 5.41 99.72
15 day at -80ºC 1551.67 ± 64.32 4.15 100.22

a Back calculated plasma concentrations.
b Expressed as % R.S.D. (S.D./mean) × 100.
c Calculated as (mean determined concentration/nominal concentration) × 100.

Table 4: Stability of curcumin in rat plasma.