Electron-capture GLC determination of phenylpropanolamine as a pentofluorophenyloxazolidine derivative

A simplified procedure is described for an electron-capture GLC determination of phenylpropanolamine in blood plasma. The method is based on derivatization of phenylpropanolamine with pentafluorobenzaldehyde at room temperature without prior extraction of the drug from plasma. The derivative, pentafluorophenyloxazolidine, is readily extracted from plasma into a small volume of hexane. Samples usually can be injected directly into the gas chromatograph without concentration of the hexane solution. Data are presented to illustrate the suitability of the method for dosage form bioavailability evaluation from plasma phenylpropanolamine levels achieved after acute oral administration of a typical dosage form.