Table 3

Unbound IC₅₀ values for fluoxetine, ezlopitant, imipramine, and quinidine on CYP2D6-catalyzed bufuralol 1′-hydroxylase activity

	Unbound Inhibition Constant (IC₅₀)
	Fluoxetine	Ezlopitant	Imipramine	Quinidine
	μM
Control	0.88 (0.20)	0.029 (0.007)	7.3 (0.8)	0.018 (0.003)
Microsomal protein concentration (mg/ml)
0.2	0.38 (0.08)	0.074 (0.021)	2.5 (0.6)	0.012 (0.002)
0.5	0.18 (0.03)	0.040 (0.019)	1.3 (0.3)	0.0095 (0.0019)
2.0	0.18 (0.02)	0.015 (0.004)	3.2 (0.5)	0.0055 (0.0009)
Phospholipid concentration (mg/ml)
0.2	0.38 (0.01)	0.039 (0.009)	2.5 (0.1)	0.019 (0.002)
0.5	0.42 (0.05)	0.013 (0.003)	2.4 (0.4)	0.012 (0.002)
2.0	1.3 (0.4)	0.0059 (0.0010)	2.4 (0.5)	0.012 (0.002)

Values represent the product of mean (S.E.) measured IC₅₀and unbound fraction.