TABLE 4

Effects of gefitinib on midazolam 1′-hydroxylase activity of CYP3A in human liver microsomes

The concentration of midazolam was 10 μM. The control activity of midazolam 1′-hydroxylase activity determined in the absence of an effecter was 0.408 nmol/min/mg protein.

Chemical	Concentration	1′-Hydroxymidazolam Formation^a
	μM	% of control
Gefitinib	5.0	221 ± 4.5^b
	10.0	304 ± 5.3^b
α-Naphthoflavone	5.0	189 ± 1.2^b
	10.0	212 ± 7.5^b

↵ a Values are represented as mean ± S.D. (n = 3).
↵ b Significant difference between values obtained in the presence or absence of an activator (P < 0.05).