On the pharmacokinetics of 16-acetyl-gitoxin and its bioavailability from pengitoxin-containing tablet formulations.
In six volunteers the pharmacokinetics of 16-acetyl-gitoxin (16AG, 0.5 mg) administered intravenously (A1) and as an oral solution (A2) and of pengitoxin (PAG, 0.6 mg) administered intravenously (A3) was evaluated. In six volunteers the bioavailability of 16AG from two PAG tablet formulations (1.2 mg) (B2, B3) was measured by comparison with the absorption after administration of a pengitoxin solution (1.2 mg) (B1). In both studies the test was performed using a crossover design. After a single i.v. injection of equimolar doses, 16AG and PAG showed similar mean kinetic parameters: t1/2 = 51.6 hr (16AG) and 60.8 hr (PAG), CL = 11.7 ml min-1 (16AG) and 12.7 ml min-1 (PAG), CLR = 4.1 ml min-1 (16AG) and 4.2 ml min-1 (PAG). The 16AG was absorbed from solution with a mean half-life of 0.2 hr to an extent of 98.6%. The mean urinary excretion/Ae (0,4)/of 16AG amounted to 24.6% (A1), 20.8% (A2) and 28.1% (A3). On the basis of AUC values, the mean bioavailability of PAG from either tablet formulation amounted to 79.6% (B2) and 89.6% (B3). The pharmacokinetic parameters of 16AG (PAG) are closer to those of digitoxin than those of digoxin. In general, 16AG is characterized as a digitoxin with a digoxin-like elimination half-life.
D000113:Acetyldigoxins / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D004074:Digitoxin / Q000378:metabolism; D004077:Digoxin / Q000031:analogs & derivatives* / Q000378:metabolism; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D013607:Tablets
D000113:Acetyldigoxins; D013607:Tablets; C016034:pentaacetylgitoxin; C025972:16-acetylgitoxin; D004077:Digoxin; D004074:Digitoxin