PT - JOURNAL ARTICLE AU - Stoupi, Stavroula AU - Williamson, Gary AU - Viton, Florian AU - Barron, Denis AU - King, Laurence J. AU - Brown, Jonathan E. AU - Clifford, Michael N. TI - In Vivo Bioavailability, Absorption, Excretion, and Pharmacokinetics of [<sup>14</sup>C]Procyanidin B2 in Male Rats AID - 10.1124/dmd.109.030304 DP - 2010 Feb 01 TA - Drug Metabolism and Disposition PG - 287--291 VI - 38 IP - 2 4099 - http://dmd.aspetjournals.org/content/38/2/287.short 4100 - http://dmd.aspetjournals.org/content/38/2/287.full SO - Drug Metab Dispos2010 Feb 01; 38 AB - Procyanidins are important biologically active compounds, but the pathway and extent of absorption and metabolism are controversial. We conducted a mass balance study to evaluate the total radioactivity excreted in urine and feces after oral administration of [14C]procyanidin B2 to male rats (n = 5). Urine and feces were collected daily from 0 to 96 h. Absolute bioavailability of 14C from [14C]procyanidin B2 was calculated as ∼82% using the values for total urinary 14C. A pharmacokinetic study measured total radioactivity in the blood (n = 9). Blood samples were collected at designated time intervals (0.5–24 h) after administration. Three treatments were used: 1) intravenous, 2) oral higher dose (21 mg/kg b.wt.), and 3) oral lower dose (10.5 mg/kg). Blood concentration of total 14C reached a maximum at ∼6 h after ingestion of [14C]procyanidin B2 (groups II and III), and area under the curve (AUC) was dependent on oral dose. After intravenous or oral administration the terminal half-lives were similar, whereas 8-fold larger values were obtained after oral dosing for total clearance and the apparent volumes of distribution. These pharmacokinetic differences explain the apparently lower 14C bioavailability (8–11%) for [14C]procyanidin calculated from blood [AUC(0–24)] values. After oral administration of [14C]procyanidin B2, 63% was excreted via urine within 4 days. The data suggest that much of the parent compound administered orally is degraded by the gut microflora before absorption and that these microbial metabolites have a different distribution from the compounds circulating after the intravenous dose.Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics