RT Journal Article
SR Electronic
T1 Absolute Oral Bioavailability and Metabolic Turnover of β-Sitosterol in Healthy Subjects
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 2026
OP 2030
DO 10.1124/dmd.112.046623
VO 40
IS 10
A1 Duchateau, Guus
A1 Cochrane, Brett
A1 Windebank, Sam
A1 Herudzinska, Justyna
A1 Sanghera, Davindera
A1 Burian, Angela
A1 Müller, Markus
A1 Zeitlinger, Markus
A1 Lappin, Graham
YR 2012
UL http://dmd.aspetjournals.org/content/40/10/2026.abstract
AB The metabolic turnover, absolute oral bioavailability, clearance, and volume of distribution for β-sitosterol were measured in healthy subjects. [14C]β-Sitosterol was used as an isotopic tracer to distinguish pulse doses from dietary sources and was administered by both oral and intravenous routes. The administered doses of [14C]β-sitosterol were in the region of 3 to 4 μg, sufficiently low as not to perturb the kinetics of β-sitosterol derived from the diet. Because the plasma concentrations of [14C]β-sitosterol arising from such low doses were anticipated to be very low, the ultrasensitive isotope ratio analytical method of accelerator mass spectrometry was used. The limit of quantification for [14C]β-sitosterol was approximately 0.1 pg/ml, the oral absolute bioavailability was just 0.41%, clearance was 85 ml/h, volume of distribution was 46 L, and the turnover was 5.8 mg/day. Given the steady-state concentrations of β-sitosterol (2.83 μg/ml), then the dietary load was calculated to be approximately 1400 mg/day.