TABLE 1

Structures of the cytochrome P450 3A4 substrates and metabolites used for the study and the standard curve slope ratio of metabolite to substrate

R₁	Substrate R₂	Substrate	Metabolite R₂	Metabolite	Slope Ratio
R₁	Substrate R₂	Substrate	Metabolite R₂	Metabolite	ESI^{^a}	CSI^{^b}
	OCH₃	1	OH	1M	0.7	1.3
	N(CH₃)₂	2	NH(CH₃)	2M	0.9	0.4
	H	3	OH	3M	1.5	0.9
	CH₃	4	CH₂OH	4M	2.6	0.5
	OCH₃	5	OH	5M	1.7	3.6
	N(CH₃)₂	6	NH(CH₃)	6M	2.5	0.7
	H	7	OH	7M	4.0	1.2
	CH₃	8	CH₂OH	8M	2.5	0.5
	OCH₃	9	OH	9M	2.4	1.9
	N(CH₃)₂	10	NH(CH₃)	10M	1.3	0.5
	H	11	OH	11M	2.1	0.9
	CH₃	12	CH₂OH	12M	2.2	0.7
	OCH₃	13	OH	13M	2.3	1.6
	N(CH₃)₂	14	NH(CH₃)	14M	2.7	3.0
	H	15	OH	15M	3.1	0.8
	CH₃	16	CH₂OH	16M	2.4	1.2
	OCH₃	17	OH	17M	3.0	1.2
	N(CH₃)₂	18	NH(CH₃)	18M	0.6	N.D.
	H	19	OH	19M	2.7	0.7
	CH₃	20	CH₂OH	20M	0.9	2.8

N.D., not determined.
↵a Slope (average) of the standard curve for metabolite versus internal standard divided by slope (average) of the standard curve for substrate versus internal standard using ESI.
↵b Slope (average) of the standard curve for metabolite versus internal standard divided by slope (average) of the standard curve for substrate versus internal standard using nanospray ionization. Slopes are presented in the supplemental data.