title: Pharmacokinetics of hydroxy-3(S)-dihydroquinidine in healthy volunteers after intravenous and oral administration.
abstract: The pharmacokinetics of hydroxy-3(S)-dihydroquinidine (HDHQ) were studied in 6 healthy volunteers following a 15 min intravenous infusion of a 300 or 400 mg dose, a 300 mg oral dose in solution and a 300 mg tablet administration on three separate occasions (random order) with at least one week intervals. Using a specific HPLC assay for HDHQ, the post-infusion and post-absorption plasma HDHQ concentrations declined bi-exponentially. Both oral forms of HDHQ were absorbed rapidly (tmax 1 h-1.2 h) with an absolute bioavailability of the oral solution (F = 0.54 to 0.93) which was not significantly different from that of the tablet (F = 0.66 to 0.90). HDHQ was rapidly and extensively distributed to the tissues with a high steady-state volume of distribution (6.82 +/- 1.85 l X kg-1). Mean elimination half-life was 6.7 +/- 1.4 h after IV infusion, 8.4 +/- 1.7 h after the oral solution and 11.3 +/- 4.4 h after the tablet administration. HDHQ was partially eliminated from the body in the unchanged non-conjugated form by the urine and renal clearance represented approximately 50% of the total body clearance. These results show that HDHQ is rapidly and almost completely absorbed and has potential for a twice daily administration regimen for the treatment of cardiac arrhythmias.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D006207:Half-Life; D006801:Humans; D007262:Infusions, Intravenous; D007700:Kinetics; D008297:Male; D011802:Quinidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism
chemical_list: C042206:3-hydroxydihydroquinidine; C014486:hydroquinidine; D011802:Quinidine