TABLE 1

Kinetic parameters for the 6β-hydroxylation of testosterone, 1′-hydroxylation of midazolam, and oxidation of nifedipine mediated by recombinant CYP3A enzymes and liver microsomes

Data were presented as mean ± S.D. (n = 3).

Substrates	Parameters	hCYP3A4	hCYP3A5	pCYP3A22	pCYP3A29	pCYP3A46	HLM	PLM
Testosterone	V_max (nmol/min per nmol P450)	6.79 ± 0.16	1.33 ± 0.05	3.52 ± 0.11^###§§§	5.97 ± 0.12^##§§§	0.83 ± 0.03^###§§§	3.67 ± 0.07	2.96 ± 0.16**
	S₅₀ (µM)	112.2 ± 6.4	136.2 ± 10.4	87.8 ± 7.4^#§§§	89.0 ± 4.6^##§§§	146.9 ± 11.9^##	77.5 ± 3.5	107.5 ± 16.9*
	CL_int (μl/min per nmol P450)	60.5	9.8	40.1	67.2	5.6	47.3	27.5
	n	1.23 ± 0.07	1.48 ± 0.13	0.98 ± 0.06	1.12 ± 0.05	1.23 ± 0.09	1.51 ± 0.10	0.82 ± 0.08
	r	0.9967	0.9921	0.9949	0.9973	0.9949	0.9912	0.9847
Midazolam	V_max (nmol/min per nmol P450)	1.07 ± 0.01	2.84 ± 0.04	0.30 ± 0^###§§§	0.49 ± 0.02^###§§§	0.37 ± 0.01^###§§§	7.98 ± 0.21	3.19 ± 0.09***
	S₅₀ (µM)	3.0 ± 0.1	5.9 ± 0.2	5.7 ± 0.02^###§	16.2 ± 0.04^###§§§	19.4 ± 0.07^###§§§	9.0 ± 0.7	22.4 ± 1.6***
	CL_int (μl/min per nmol P450)	360.9	480.3	52.3	30.6	18.9	891.1	142.4
	n	1.14 ± 0.03	1.04 ± 0.03	0.98 ± 0.17	1.03 ± 0.04	1.26 ± 0.07	0.92 ± 0.04	1.17 ± 0.07
	r	0.9989	0.9993	0.9997	0.9987	0.9971	0.9978	0.9923
Nifedipine	V_max (nmol/min per nmol P450)	1.46 ± 0.04	1.95 ± 0.06	1.05 ± 0.03^###§§§	1.67 ± 0.02^###§§§	1.20 ± 0.05^##§§§	1.93 ± 0.05	4.18 ± 0.21***
	S₅₀ (µM)	12.6 ± 0.9	28.5 ± 2.2	28.5 ± 2.7^###	31.2 ± 0.7^###	63.0 ± 6.4^###§§§	17.5 ± 1.3	34.7 ± 4.5**
	CL_int (μl/min per nmol P450)	115.6	68.5	36.9	53.3	19.0	109.9	120.3
	n	1.10 ± 0.07	1.12 ± 0.06	0.90 ± 0.04	1.21 ± 0.02	0.92 ± 0.03	1.10 ± 0.07	1.02 ± 0.08
	r	0.9957	0.9978	0.9983	0.9997	0.9990	0.9933	0.9918

n, Hill coefficient; r, regression coefficient.
Statistically significant difference compared with HLM (*P < 0.05; **P < 0.01; ***P < 0.001).
Statistically significant difference compared with hCYP3A4 (^#P < 0.05; ^##P < 0.01; ^###P < 0.001).
Statistically significant difference compared with hCYP3A5 (^§P < 0.05; ^§§P < 0.01; ^§§§P < 0.001).