Determination of dextrorphan in plasma and evaluation of bioavailability of dextromethorphan hydrobromide in humans

A method is described for the estimation of dextrorphan, a metabolite of dextromethorphan, in plasma. The bioavailability of dextromethorphan hydrobromide after 30 mg po, as measured by the concentration of total (free and conjugated) dextrorphan in the plasma, was determined in six human volunteers with this procedure.