Determination of prenalterol in plasma and in urine by gas-liquid chromatography.

A description is given of a gas-liquid chromatographic method for the quantitative determination of unchanged prenalterol in plasma and for the total (free and conjugated) prenalterol in urine. After addition of an adequate internal standard, prenalterol together with the internal standard, is extracted with diethyl ether and derivatized with heptafluorobutyric anhydride-pyridine to form a tri-heptafluorobutyric derivative. This derivative has favourable properties for its estimation by gas-liquid chromatography using electron-capture detection. A large percentage of prenalterol is excreted as sulfate conjugate in man. Thus a hydrolysis step is added to the urine assay. The sensitivity of the method is about 2ng/ml.