Gas chromatographic determination of dimethophrine in biological specimens of rabbit.

A method to measure the alpha-sympathomimetic amine, 1-(3,5-dimethoxy-4-hydroxyphenyl)-2-monomethyl-amino-ethanol (dimethophrine, DMP), was developed and applied for the determination of the drug in biological specimens. The gas chromatographic degradation of the drug was investigated, and in order to avoid this process, DMP is converted to the trifluoroacetyl derivative and assayed by gas liquid chromatography on an OV 1' column. The minimum detectable amount is 25 pg per injection. Linearity (using hexachlorobenzene as internal standard for quantitation) was found up to mug amounts of the substance, without any interference with endogenous substrates. Values from plasma, red blood cells and urine in rabbits treated with a single dose of DMP (10 mg/kg) are also reported.