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

Table 3

Intra- and interday precision (RSD, %) and accuracy (bias, %) of QC samples.

Compound	Nominal concentration (ng/mL)	Intraday			Interday
		Observed concentration (ng/mL)	RSD (%)	Bias (%)	Observed concentration (ng/mL)	RSD (%)	Bias (%)
Promethazine	0.5	0.52	12.57	4.56	0.50	16.97	1.01
	1.25	1.19	8.91	−4.02	1.17	11.22	−5.61
	12.5	11.79	6.56	−5.60	11.79	9.24	−5.61
	150	137.95	10.47	−8.02	140.96	13.31	−6.02
Promethazine sulfoxide	0.5	0.52	6.84	5.63	0.54	6.24	9.44
	1.25	1.26	1.37	1.23	1.28	6.10	2.56
	12.5	13.92	5.09	11.40	13.84	5.10	10.74
	150	138.65	3.54	−7.56	137.21	8.18	−8.52
Schisandrin	0.5	0.53	5.37	6.49	0.49	12.56	−1.95
	1.25	1.29	9.44	3.88	1.28	6.07	2.51
	12.5	13.09	6.15	4.75	13.17	6.25	5.43
	150	156.50	5.32	4.33	156.69	6.39	4.46