Abstract
Gas chromatographic method has been devised for the determination of oxprenolol, an adrenergic β-receptor blocking agent, in blood after oral administration of an officinal dose. This compound showed a single peak with satisfactory sensitivity, when treated with trifluoroacetic anhydride and then applied to gas chromatograph equipped with a 1.5% OV-1 column and an electron capture detector. The calibration curve for quantitation was constructed with the use of p, p'-DDE(1, 1-dichloro-2, 2-bis(p-chlorophenyl) ethylene) as an internal standard. Separation of the drug from blood was attained by extraction with ether-dichloromethane followed by partition with dilute hydrochloric acid. The derived product from oxprenolol thus separated was identified as the N, O-bis(trifluoroacetate) by means of gas chromatography-mass spectrometry. A known amount of oxprenolol added to blood plasma was recovered at the rate of ca. 96% by this procedure. The amount of the unchanged drug in blood after oral administration to man was determined by the established method.
