Table 4. Stability of the nine compounds in rat plasma samples.

Concentration (µg/mL)	Stability (%)
	Freeze-thaw stability	Short-term stability	Long-term stability	Autosampler stability
Astragaloside I
1	4.6±3.6	−3.6±8.0	−14±17	−5.3±7.9
10	3.8±2.7	−4.1±10	−8.3±2.3	4.3±6.6
100	−1.8±5.4	−6.4±6.4	−27±12	−4.9±7.0
Astragaloside II
1	4.4±3.6	2.4±12	8.7±10	13±10
10	−2.3±0.8	−1.3±1.9	−0.8±16	−0.3±11
100	0.4±1.2	−6.8±5.7	1.7±21	−5.4±13
Astragaloside IV
1	−3.2±5.0	12±15	−17±5.3	3.8±9.8
10	−4.1±3.4	4.7±6.2	−6.3±8.8	3.3
100	6.1±0.4	1.6±9.1	2.1±13.5	−8.6±12
Formononetin
10	−4.9±3.8	−3.4±12	−13±5.5	−13±4.1
100	5.8±10	1.1±10	−12±7.5	−4.6±11
1000	−3.5±6.0	1.5±10.4	1.0±6.4	0.8±12
Ononin
1	3.9±6.4	12±6.3	−7.2±10	4.7±7.7
10	−2.5±7.3	−12±4.6	−6.2±2.9	−7.0±1.4
100	4.2±1.3	6.7±2.1	3.2±3.9	8.1±3.8
Calycosin
10	9.6±4.7	1.4±11	2.5±5.7	−3.5±11
100	8.6±3.8	14±12	17±5.2	−2.2±3.5
1000	2.9±4.5	13±7.3	21±12	7.1±4.9
Calycosin-7-O-β-D-glucoside
1	5.8±6.1	2.5±11	6.4±12	−8.4±12
10	4.9±3.5	7.3±12	23±13	2.1±9.1
100	7.0±1.2	−0.1±0.9	20±12	3.5±7.9
Ligustilide
1	8.7±5.9	14±11	6.7±10	2.0±10
10	2.7±2.2	11±10	5.0±14	13±7.2
100	6.5±1.4	12±7.5	23±12	−1.6±10
Paeoniflorin
10	7.3±4.6	7.7±10	21±15	−3.3±7.3
100	2.1±1.8	−1.8±9.4	10±7.3	−1.6±8.2
1000	9.5±0.2	11±8.4	27±9.9	8.5±5.1

Data are expressed as means ± S.D. (n = 3).