title: Reverse-phase liquid chromatography and pharmacokinetic study of two hydroxylated analogues of quinidine in dogs.
abstract: Two hydroxylated analogues of quinidine with antiarrhythmic properties, 3S-hydroxyquinidine and 3R-hydroxydihydroquinidine were assayed by reverse-phase high-performance liquid chromatography. The analytical technique uses plasma protein precipitation and direct injection on a C18 column, with an isocratic mobile phase and spectrofluorometric detection. 3R-Hydroxyquinidine is employed as the internal standard. Linearity is verified up to 5 mg/L for the two drugs; concentrations between 0.5 and 2.5 mg/L were measured with a CV of 0.5-2.07% for a given day and a sensitivity limit of 50 micrograms/L. Plasma concentration-time profiles and pharmacokinetic parameters in three dogs are presented after intravenous or oral administration. A significant difference is observed in terminal half-life, terminal rate constant, and total clearance of the two polar analogues of quinidine.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004285:Dogs; D007275:Injections, Intravenous; D007700:Kinetics; D011802:Quinidine / Q000031:analogs & derivatives* / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: C013569:3-hydroxyquinidine; C042206:3-hydroxydihydroquinidine; D011802:Quinidine