Table 2.

Stability in rat plasma, urine, and feces (n = 5).

Biological Sample	Theoretical Concentration (μg/mL)	24 h at Room Temperature		Repeated Freeze-Thaw Test for 3 Times		Frozen at −20 °C for 15 Days
		Measured Concentration (μg/mL)	RSD (%)	Measured Concentration (μg/mL)	RSD (%)	Measured Concentration (μg/mL)	RSD (%)
Plasma	0.2	0.196 ± 0.004	4.90	0.194 ± 0.005	4.98	0.191 ± 0.003	3.80
	2.0	1.89 ± 0.02	2.07	1.93 ± 0.04	4.03	1.96 ± 0.03	3.24
	20.0	19.17 ± 0.34	3.74	19.03 ± 0.24	2.72	19.49 ± 0.17	1.87
Urine	0.25	0.246 ± 0.004	4.61	0.244 ± 0.005	4.98	0.247 ± 0.003	4.78
	50	48.89 ± 0.82	1.07	49.93 ± 0.74	1.83	49.96 ± 0.83	1.34
	500	498.17 ± 3.34	0.74	496.03 ± 2.24	0.72	498.49 ± 3.17	0.89
Feces	5.0	4.92 ± 0.14	3.64	4.86 ± 0.12	4.02	4.96 ± 0.13	3.82
	50.0	48.89 ± 0.22	2.11	46.93 ± 0.34	5.36	48.96 ± 0.23	4.64
	300.0	287.63 ± 0.34	3.28	279.08 ± 0.24	2.72	292.44 ± 0.31	2.81