HPLC Method Determination of Isoliquiritin Apioside and Isoliquiritin in Rat Plasma for Application in Pharmacokinetic Study after an Oral Administration of Zhigancao Extract

Table 2

Stability of ILA and IL under various conditions in plasma (𝑛=3).

Analyte	Spiked concentration; (μg/mL)	Stored at room temperature for 12 h		Three freeze-thaw stability		Stored at −20°C for 15 days
		Measured; concentration (μg/mL)	RE (%)	Measured; concentration (μg/mL)	RE (%)	Measured; concentration (μg/mL)	RE (%)
ILA	0.12	0.12 ± 0.001	2.7	0.12 ± 0.003	−0.5	0.12 ± 0.002	−0.5
	0.48	0.48 ± 0.008	−3.6	0.45 ± 0.018	−5.6	0.48 ± 0.002	0.07
	3.07	3.07 ± 0.028	0.03	2.91 ± 0.029	−5.2	2.97 ± 0.006	−3.2
IL	0.15	0.16 ± 0.005	4.3	0.16 ± 0.006	3.9	0.15 ± 0.004	−2.6
	0.6	0.59 ± 0.015	−1.1	0.62 ± 0.019	2.7	0.57 ± 0.010	−4.4
	3.84	3.82 ± 0.065	−0.4	3.85 ± 0.077	0.19	3.72 ± 0.157	−3.2