TABLE 1.

Comparison of the plasma pharmacokinetics determined after a single-bolus, 20-mg dose of S-(−)[2-¹³C]equol, R-(+)[2-¹³C]equol, and (±)[2-¹³C]equol in the same 12 healthy adults¹

	R-(+)[2-13C]equol	S-(−)[2-13C]equol	(±)[2-13C]equol
tmax (h)	2.92 ± 0.66	3.17 ± 0.63	5.75 ± 0.87
Cmax (nmol/L · h)	1202 ± 1482	991 ± 1292	567 ± 66
AUCinf (nmol/L · h)	12,230 ± 7702	11,048 ± 1276	9047 ± 1001
Vz/F (L)	71.3 ± 8.2	96.2 ± 12.4	132 ± 23.8
t1/2 (h)	6.90 ± 0.52	7.89 ± 0.69	8.15 ± 0.53
Cl/F (L/h)	7.08 ± 0.423	8.73 ± 1.23	10.73 ± 1.44

¹All values are means ± SEMs. t_max, time to reach maximum concentration; C_max, maximum plasma concentration; AUC_inf, total area under the plasma concentration-time curve; Vz/F, apparent volume of distribution; t_1/2, terminal elimination half-life; Cl/F, systemic clearance. Repeated-measures ANOVA were calculated for each test, and matched-pairs t tests were conducted with Bonferroni correction for multiple comparisons.

²Significantly different from (±)[2-¹³C]equol, P < 0.05.

³Significantly different from S-(−)[2-¹³C]equol and (±)[2-¹³C]equol, P < 0.05.