A thin-layer chromatographic method for the determination of acebutolol and its major metabolite in serum

A sensitive and specific thin-layer chromatographic method for the simultaneous determination of acebutolol [DL-1-(2-acetyl-4-n-butyramidophenoxy)-2-hydroxy-3-isopropylaminopropane] and its major metabolite [DL-1-(2-acetyl-4-acetamidophenoxy)-2-hydroxy-3-isopropylaminopropane] is described. A 2-ml volume of serum with 350 ng of quinidine as internal standard was extracted at pH 10, the solvent was evaporated off and the residue was dissolved in 50 mul of methanol. A 10-mul volume of the solution was spotted on a thin-layer plate and after elution (ethyl acetate-methanol-ammonia, 75:20:5) the plate was dried at 90 for 15 min and, after cooling, dipped in a 10% paraffin wax solution. The fluorescence was measured using a spectrofluorimeter with a thin-layer scanning attachment. The peak-height ratios of acebutolol to internal standard and metabolite to internal standard were used to quantitate acebutolol and the metabolite, respectively.