DETERMINATION OF DEXAMETHASONE IN LIVER AND MUSCLE BY LIQUID-CHROMATOGRAPHY AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The rapid determination of dexamethasone (DEX) in bovine, porcine, and ovine liver and muscle has been accomplished by using a new extraction method. In liver, this procedure consists of adding sodium hydroxide to the tissue sample followed by extraction with ethyl acetate. After centrifugation, the organic supernatant underwent silica gel solid phase extraction. Muscle tissue can be analyzed by adding an acetonitrile/hexane partitioning step to this method. Analysis of the extracts is performed by using reversed-phase HPLC. A series of recovery curves performed at spiking levels of 5, 10, and 20 ppb have demonstrated that 70 and 60% of DEX can be recovered from liver and muscle tissue, respectively. A subsequent study indicated that this analytical procedure has a detection limit of 1.4 ppb. A variation of a previously published gas chromatographic/mass spectral (GC/MS) method for the analysis of dexamethasone in plasma has been used for the confirmation of DEX in extracts generated by the determinative method.