DETERMINATION OF DESMETHYLSELEGILINE, METHAMPHETAMINE AND AMPHETAMINE- THE MAIN METABOLITES OF SELEGILINE IN PLASMA BY HPLC AFTER DERIVATIZATION

Determination of desmethylselegiline, methamphetamine and amphetamine in plasma requires a very sensitive and selective method. These substa nces are metabolites of the MAO-inhibitor selegiline. This is the firs t published HPLC method which is able to determine these three substan ces down to a limit of quantification of 0.2 ng/mL human plasma. After extraction as free bases into an organic solvent and reextraction as salts into an inorganic acid all three substances and an internal stan dard (phentermine) are derivatized for fluorescence detection after re versed phase chromatography. The recovery is better than 90% for all s ubstances. The linearity in the range tested (0.2 - 15 ng for each sub stance/ml plasma) is very good indeed. The precision and accuracy is u sually smaller than 5%. Pharmacokinetic results are presented.