β-Blocking Agents: Determination of Biological Levels Using High Performance Liquid Chromatography

Abstract

Nine .beta.-blocking agents were tested and dosed by high performance liquid chromatography [HPLC]. Six of them, acebutolol, an acebutolol metabolite, atenolol, metoprolol, propranolol and sotalol are detected with a fluorometric detector. Oxprenolol, pindolol and timolol can be quantified by their UV absorption at variable wavelength. A method is developed to find the best conditions of extraction and detection for each blocking agent. Experimental trials have led to a simple procedure for all compounds. Only pindolol and timolol plasma levels are not suitable for HPLC and need mass fragmentography or gas chromatography with electron capture detection. Pharmacokinetic parameters can be reached, for timolol and pindolol, through urinary excretion [in man] as sensitivity of the procedure is within the range of urinary levels. The method was applied to pharmacokinetic studies on sotalol, acebutolol, acebutolol metabolite, atenolol, propranolol, pindolol and timolol.