A validated gas chromatographic-electron impact ionization mass spectrometric method for methamphetamine, methylenedioxymethamphetamine (MDMA), and metabolites in mouse plasma and brain

Abstract

A method was developed and fully validated for simultaneous quantification of methamphetamine (MAMP), amphetamine, hydroxy-methamphetamine, methylenedioxymethamphetamine (MDMA, ecstasy), methylenedioxyamphetamine, 3-hydroxy-4-methoxy-methamphetamine, and 3-hydroxy-4-methoxy-amphetamine in 100 microL mouse plasma and 7.5mg brain. Solid phase extraction and gas chromatography-electron impact ionization mass spectrometry in selected-ion monitoring mode achieved plasma linear ranges of 10-20 to 20,000 ng/mL and 0.1-0.2 to 200 ng/mg in brain. Recoveries were greater than 91%, bias 92.3-110.4%, and imprecision less than 5.3% coefficient of variation. This method was used for measuring MAMP and MDMA and metabolites in plasma and brain during mouse neurotoxicity studies.

Fig. 1

100 μL of plasma fortified with drug standards at each analyte’s limit of quantification (A: 10 ng/mL amphetamine, B: 10 ng/mL methamphetamine, C: 20 ng/mL hydroxy-methamphetamine, D: 20 ng/mL 3-hydroxy-4-methoxy-amphetamine, E: 20 ng/mL 3-hydroxy-4-methoxy-methamphetamine, F: 10 ng/mL methylenedioxyamphetamine and G: 10 ng/mL methylenedioxymethamphetamine).

Fig. 2

7.5 mg blank brain fortified with drug standards at each analyte’s limit of quantification (A: 0.1 ng/mg amphetamine, B: 0.1 ng/mg methamphetamine, C: 0.2 ng/mg hydroxy-methamphetamine, D: 0.2 ng/mg 3-hydroxy-4-methoxy-amphetamine, E: 0.1 ng/mg 3-hydroxy-4-methoxy-methamphetamine, F: 0.1 ng/mg methylenedioxyam-phetamine and G: 0.1 ng/mg methylenedioxymethamphetamine). Note: injection was made after capillary column replacement, therefore retention times do not match Fig. 1.