HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF )-(5-FLUORO-2-HYDROXYPHENYL)-METHYLENEAMINOBUTYRIC ACID AND ITS BENZOPHENONE METABOLITE

The high-performance liquid chromatographic determination of [C-11]MPG A l)-(5-fluoro-2-hydroxyphenyl)methyleneaminobutyric acid} and [C-11]M BENZ (5-fluoro-2-hydroxy-4'-[C-11]methoxybenzophenone) is described. T he method was successfully applied to the quality control of [C-11]MPG A radiopharmaceutical preparations and for plasma analysis after i.v. injection of [C-11]MPGA into mice. For determination in plasma, rapid extraction with dichloromethane from buffered plasma (pH 4.5), prior t o chromatography, is necessary. Separation is effected on an RP-C-18 c olumn, using a mixture of 0.05 M potassium phosphate-0.025 M citric ac id (pH 6.5) and methanol (42:58, v/v) as the mobile phase. Detection i s achieved using an ultraviolet absorption detector set at 255 nm in c ombination with an NaI (Tl) detector. Quantitative measurements of rad ioactivity are performed on a one-channel gamma-ray spectrometer. The linearity, precision and accuracy for the method are also provided.