title: Spironolactone. I. Disposition and metabolism.
abstract: This study describes absorption, excretion, and metabolism of[20(-3)H]-spironolactone (SP) in 5 healthy men. After a single oral dose (200 mg + 200 muCi) of the drug given in alcoholic solution, the peak serum levels of the ethyl acetate-extractable tritium and the dethioacetylated metabolite canrenone were 763 +/- 400 ng/ml (mean +/- SD) and 415 +/- 145 ng/ml, respectively. These levels occurred within 3 hr. The serum half-life (T1/2) of the extractable materials was 37.3 +/- 6.53 hr. Canrenone levels declined in two phases. The T1/2 from 2.5 to 12 hr was 4.42 +/- 1.07 hr and from 12 to 72 hr was 16.8 +/- 2.75 hr. In the blood both SP and canrenone were confined largely in the plasma, and their protein binding exceeded 89% at concentrations of 550 and 710 ng/ml, respectively. In 5 days 31.6 +/- 5.87% of the radioactivity was excreted in the urine and 22.7 +/- 14.1% in the feces. Unchanged SP was not detected in the urine. The major urinary metabolites were canrenone (5.04 +/- 2.83% of dose), 6beta-OH-sulfoxide (5.21 +/- 0.93% of dose), and canrenoate ester glucuronide (6.2% of dose).
mesh_terms: D000328:Adult; D002192:Canrenone / Q000097:blood; D004355:Drug Stability; D004912:Erythrocytes / Q000378:metabolism; D005243:Feces / Q000032:analysis; D006207:Half-Life; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D011485:Protein Binding; D013148:Spironolactone / Q000097:blood / Q000378:metabolism* / Q000652:urine; D013997:Time Factors
chemical_list: D013148:Spironolactone; D002192:Canrenone