Table 1.

Intra- and inter-day accuracy and precision of carvedilol and 4/-hydroxyphenyl carvedilol.

Analytes	QC level (ng/mL)	Intra-day (n = 5)			Inter-day (3 days)
		Mean concentration (ng/mL)	Accuracy (%)	Precision, CV (%)	Mean concentration (ng/mL)	Accuracy (%)	Precision, CV (%)
	LLOQ (0.050)	0.046	91.200	11.769	0.051	102.667	8.998
Carvedilol	LQC (0.150)	0.149	99.333	8.096	0.150	99.778	10.697
	MQC (15.000)	15.907	106.049	2.455	15.417	102.782	6.959
	HQC (40.000)	38.618	96.545	2.386	39.202	98.006	4.018
	LLOQ (0.050)	0.053	105.600	8.190	0.055	110.667	3.762
4/-Hydroxy-	LQC (0.150)	0.138	92.000	8.166	0.148	98.444	9.633
phenyl carvedilol	MQC (2.999)	3.015	100.540	4.169	2.973	99.144	7.315
	HQC (7.998)	7.102	88.792	9.671	7.324	91.569	8.843

QC, Quality control; LLOQ, lower limit of quantification; LQC, low quality control; MQC, medium quality control; HQC, high quality control.