Quantitative determination of propranolol, propranolol glycol and N-desisopropylpropranolol in brain tissue by electron capture gas chromatography

A method for the quantitative determination of propranolol and two of its active metabolites, 3-(alpha-naphthoxy)-1,2-propanediol (propranolol glycol) and N-des-isopropylpropranolol, in brain tissue of mice is described. Tissues are homogenized in perchloric acid-acetonitrile. Propranolol and its metabolites are isolated from the supernatant by solvent extraction and separated and detected as their trifluoroacetyl derivatives by electron capture gas chromatography. Chemical structures of the derivatives were confirmed by gas chromatography-mass spectrometry. The electron capture detector response of all three compounds is high, 0.7-2.0 X 10(-16) moles/sec. Brain levels of 10-250 ng/g can be detected of all three compounds with high specificity and good precision.