Pharmacokinetic Comparative Study of Gastrodin and Rhynchophylline after Oral Administration of Different Prescriptions of Yizhi Tablets in Rats by an HPLC-ESI/MS Method

Table 5

Stability of GAS, HBA, and RIN in rat plasma by HPLC-MS method ().

Marker compounds	Concentration (g/mL)	Stability (RE, %)
		−80^°C/20 days	Freeze-thaw (3 cycles)	20^°C/24 h
GAS	100	8.01	8.26	3.93
	50	6.95	4.12	3.17
	10	4.38	5.36	9.35
HBA	100	7.15	7.03	3.17
	50	5.63	4.65	2.65
	10	4.58	2.65	4.69
RIN	10	5.49	4.56	9.35
	5	8.04	8.08	7.65
	1	6.88	7.18	8.63