Gas chromatographic determination of amantadine hydrochloride (Symmetrel) in human plasma and urine.

A method for the determination of amantadine hydrochloride at concentrations down to 10 ng/ml in human plasma and urine is described. After addition of a known amount of amphetamine sulphate as internal standard to 1 ml of plasma or urine, amantadine is extracted at basic pH in toluene. Both compounds are derivatized with trichloroacetyl chloride. The derivatives are determined by gas chromatography using a 63Ni electron-capture detector. The technique was applied in a study of the elimination of amantadine after oral administration to man; plasma concentrations are reported.