Simultaneous Determination of Schisandrin and Promethazine with Its Metabolite in Rat Plasma by HPLC-MS/MS and Its Application to a Pharmacokinetic Study

Table 5

Stability of the analytes in rat plasma under different storage conditions.

Compound	Nominal concentration (ng/mL)	Short-term storage (4 h)		Autosampler stability (24 h)		Freeze-thaw stability
		RSD (%)	Bias (%)	RSD (%)	Bias (%)	RSD (%)	Bias (%)
Promethazine	0.5	12.93	−1.68	4.90	4.96	10.87	−0.83
	1.25	12.91	−9.38	12.46	10.59	11.58	−3.21
	12.5	9.01	−1.44	14.55	6.20	8.20	−2.41
	150	6.37	6.10	9.39	−6.50	2.89	2.074
Promethazine sulfoxide	0.5	8.039	−4.51	7.74	−1.48	5.38	6.71
	1.25	7.87	−6.86	3.59	7.19	5.47	1.48
	12.5	6.52	−1.58	7.88	11.41	2.26	3.78
	150	7.71	−5.23	3.78	−10.28	2.63	−8.28
Schisandrin	0.5	13.14	−1.88	10.01	−13.03	17.20	−5.05
	1.25	11.09	−3.29	5.35	−6.60	4.40	−9.02
	12.5	2.74	−1.92	1.55	−6.62	4.36	−1.19
	150	1.84	−2.24	10.52	−11.38	3.92	−2.56