title: Bioavailability of disopyramide in normal volunteers using unbound concentration.
abstract: The pharmacokinetics of disopyramide were determined in 10 healthy volunteers after a 300 mg oral dose and again after a 2 mg/kg i.v. dose. The unbound clearance was 599 ml/min and the unbound renal clearance 310 ml/min. The terminal elimination rate constant of unbound drug was 0.180 h-1 after the i.v. dose and 0.203 h-1 after the oral dose. The absorption rate constant was 0.53(-1) and the maximum peak concentration occurred after 3.2 h. The bioavailability was 0.809 using the area under the unbound plasma concentration time curve. Although a saturable plasma protein binding was found in all subjects the bioavailability using the total concentration, in contrast to theoretical expectations, showed the same value (0.813) as the unbound concentrations.
mesh_terms: D000328:Adult; D001682:Biological Availability; D001798:Blood Proteins / Q000378:metabolism; D004206:Disopyramide / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D011485:Protein Binding
chemical_list: D001798:Blood Proteins; D004206:Disopyramide