AJAC  Vol.4 No.4 , April 2013
Comparative in Vitro Studies of the Metabolism of Six 4-Substituted Methamphetamines and Their Inhibition of Cytochrome P450 2D6 by GC-MS with Trifluoroacetyl Derivatization
Abstract: Use of new amphetamine-type stimulants (ATS) as designer drugs is a serious problem worldwide. ATS are used in tablet, capsule, and powder forms, and can be mixed with other drugs. There is little information available on how these new drugs are metabolized or their ability to inhibit the metabolism of co-administered drugs. This study aimed to investigate the metabolism of six 4-substituted analogs of methamphetamine (MA), and their potential inhibition of MA metabolism. The metabolism of MA and the 4-substituted MAs was examined in vitro using human metabolic enzymes. Metabolite analyses were performed using trifluoroacetyl derivatization and GC-MS. The experiments showed that cytochrome P450 2D6 (CYP2D6) was involved in the major metabolic pathway of MA, where it catalyzed N-demethylation of 4-fluoromethamphetamine (4-FMA), 4-chloromethamphetamine (4-CMA), 4-bromomethamphetamine (4-BMA), 4-iodomethamphetamine (4-IMA) and 4-nitromethamphetamine (4-NMA), and O-demethylation of 4-methoxymethamphetamine (4-MMA). The half maximal inhibitory concentration (IC50) values for CYP2D6 using MA as substrate were different for each of the 4-substituted MAs. The strongest inhibitors of amphetamine production from MA were, in order, 4-IMA, 4-BMA, 4-CMA, 4-MMA, 4-FMA, and 4-NMA. The same order was observed for the IC50 values for inhibition of p-hydroxymethamphetamine production from MA, except for the IC50 of 4-MMA. The IC50 values of 4-IMA were lower than the IC50 values of fluoxetine and higher than that of quinidine. The results of this study imply that the risk of illicit drug interactions fluctuates so widely that unintentional fatal drug poisonings could occur.
Cite this paper: M. Taniguchi, Y. Yamamoto and K. Nishi, "Comparative in Vitro Studies of the Metabolism of Six 4-Substituted Methamphetamines and Their Inhibition of Cytochrome P450 2D6 by GC-MS with Trifluoroacetyl Derivatization," American Journal of Analytical Chemistry, Vol. 4 No. 4, 2013, pp. 166-175. doi: 10.4236/ajac.2013.44022.

[1]   [1] J. Becker, P. Neis, J. Röhrich and S. Zörntlein, “A Fatal Paramethoxymethamphetamine Intoxication,” Legal Medicine (Tokyo, Japan), Vol. 5, 2003, pp. S138-S141. doi:10.1016/S1344-6223(02)00096-2

[2]   S. S. Johansen, A. C. Hansen, I. B. Müller, J. B. Lundemose and M. B. Franzmann, “Three Fatal Cases of PMA and PMMA Poisoning in Denmark,” Journal of Analytical Toxicology, Vol. 27, No. 4, 2003, pp. 253-256.

[3]   R. Dams, E. A. De Letter, K. A. Mortier, J. A. Cordonnier, W. E. Lambert, M. H. Piette, S. Van Calenbergh and A. P. De Leenheer, “Fatality Due to Combined Use of the Designer Drugs MDMA and PMA: A Distribution Study,” Journal of Analytical Toxicology, Vol. 27, No. 5, 2003, pp. 318-322.

[4]   E. A. De Letter, W. E. Lambert, M. P. Bouche, J. A. Cordonnier, J. F. Van Bocxlaer and M. H. Piette, “Postmortem Distribution of 3,4-Methylenedioxy-N,N-dimethyl-amphetamine (MDDM or MDDA) in a Fatal MDMA Overdose,” International Journal of Legal Medicine, Vol. 121, No. 4, 2007, pp. 303-307. doi:10.1007/s00414-006-0094-x

[5]   G. P. Dowling, E. T. McDonough and R. O. Bost, “‘Eve’ and ‘Ecstasy’. A Report of Five Deaths Associated with the Use of MDEA and MDMA,” The Journal of American Medical Association, Vol. 257, No. 12, 1987, pp. 1615- 1617. doi:10.1001/jama.1987.03390120077027

[6]   J. A. Henry, K. J. Jeffreys and S. Dawling, “Toxicity and Deaths from 3,4 Methylenedioxymethamphetamine (‘Ecstasy’),” Lancet, Vol. 340, No. 8816, 1992, pp. 384-387. doi:10.1016/0140-6736(92)91469-O

[7]   S. Iwersen and A. Schmoldt, “Two Very Different Fatal Cases Associated with the Use of Methylenedioxyethylamphetamine (MDEA): Eve as Deadly as Adam,” Journal of Toxicology—Clinical Toxicology, Vol. 34, No. 2, 1996, pp. 241-244. doi:10.3109/15563659609013778

[8]   R. F. Staack, D. S. Theobald, L. D. Paul, D. Springer, T. Kraemer and H. H. Maurer, “Identification of Human Cytochrome P450 2D6 as Major Enzyme Involved in the O- Demethylation of the Designer Drug p-Methoxymethamphetamine,” Drug Metabolism and Disposition, Vol. 32, No. 4, 2004, pp. 379-381. doi:10.1124/dmd.32.4.379

[9]   K. Zaitsu, M. Katagi, T. Kamata, H. Kamata, N. Shima, H. Tsuchihashi, T. Hayashi, H. Kuroki and R. Matoba, “Determination of a Newly Encountered Designer Drug ‘p-Methoxyethylamphetamine’ and Its Metabolites,” Forensic Science International, Vol. 177, No. 1, 2008, pp. 77-84. doi:10.1016/j.forsciint.2007.11.001

[10]   P. Rösner, B. Quednow, U. Girreser and T. Junge, “Isomeric Fluoro-Methoxy-Phenylalkylamines: A New Series of Controlled-Substance Analogues (Designer Drugs),” Forensic Science International, Vol. 148, No. 2-3, 2005, pp. 143-156. doi:10.1016/j.forsciint.2004.05.003

[11]   M. Nagashima, T. Seto, M. Takahashi, J. Suzuki and I. Yasuda, “Spectrum Data of the 3rd Governor-Designated Drugs and the Analyses of Uncontrolled Drugs Purchased April 2005-March 2006,” Tokyo Metropolitan Institute of Public Health Annual Report (in Japanese), Vol. 57, 2006, pp. 109-113.

[12]   J. C. Cole, M. Bailey, H. R. Sumnall, G. F. Wagstaff and L. A. King, “The Content of Ecstasy Tablets: Implications for the Study of Their Long-Term Effects,” Addiction, Vol. 97, No. 12, 2002, pp. 1531-1536. doi:10.1046/j.1360-0443.2002.00222.x

[13]   C. M. Milroy, J. C. Clark and A. R. W. Forrest, “Pathology of Deaths Associated with ‘Ecstasy’ and ‘Eve’ Misuse,” Journal of Clinical Pathology, Vol. 49, No. 2, 1996, pp. 149-153. doi:10.1136/jcp.49.2.149

[14]   Y. Makino, S. Tanaka, S. Kurobane, M. Nakauchi, T. Terasaki and S. Ohta, “Profiling of Illegal Amphetamine- Type Stimulant Tablets in Japan,” Journal of Health Science, Vol. 49, No. 2, 2003, pp. 129-137. doi:10.1248/jhs.49.129

[15]   A. Camilleri, M. R. Johnston, M. Brennan, S. Davis and D. G. Caldicott, “Chemical Analysis of Four Capsules Containing the Controlled Substance Analogues 4-Methylmethcathinone, 2-Fluoromethamphetamine, Alpha-Phthalimidopropiophenone and N-Ethylcathinone,” Forensic Science International, Vol. 197, No. 1-3, 2010, pp. 59-66. doi:10.1016/j.forsciint.2009.12.048

[16]   F. Caudevilla-Gálligo, J. Riba, M. Ventura, D. González, M. Farré, M. J. Barbanoj and J. C. Bouso, “4-Bromo-2,5- dimethoxyphenethylamine (2C-B): Presence in the Recreational Drug Market in Spain, Pattern of use and Subjective Effects,” Journal of Psychopharmacology, Vol. 26, No. 7, 2012, pp. 1026-1035. doi:10.1177/0269881111431752

[17]   T. M. Brunt, M. W. Koeter, R. J. Niesink and W. van den Brink, “Linking the Pharmacological Content of Ecstasy Tablets to the Subjective Experiences of Drug Users,” Psychopharmacology (Berl), Vol. 220, No. 4, 2012, pp. 751-762. doi:10.1007/s00213-011-2529-4

[18]   M. Taniguchi, Y. Yamamoto and K. Nishi, “A Technique Combining Trifluoroacetyl Derivatization and Gas Chromatography-Mass Spectrometry to Distinguish Methamphetamine and Its 4-Substituted Analogs,” Journal of Mass Spectrometry, Vol. 45, No. 12, 2010, pp. 1473-1476. doi:10.1002/jms.1851

[19]   J. B. Ledgard, “A Laboratory History of Narcotics, Amphetamines and Derivatives,” 2007.

[20]   M. H. Beers and R. Berkow, “The Merck Manual,” 17th Edition, Merck & Co., Inc., Pennsylvania, 1999.

[21]   R. F. Borch, M. D. Bernstein and H. D. Durst, “Cyanohydridoborate Anion as a Selective Reducing Agent,” Journal of the American Chemical Society, Vol. 93, No. 12, 1971, pp. 2897-2904. doi:10.1021/ja00741a013

[22]   R. S. Frank, “The Clandestine Drug Laboratory Situation in the United States,” Journal of Forensic Sciences, Vol. 28, No. 1, 1983, pp. 18-31.

[23]   T. Inoue, S. Suzuki and T. Niwaguchi, “Stability of Perfluoroacyl Derivatives of Methamphetamine and Its Metabolites,” Eisei Kagaku (in Japanese), Vol. 29, No. 6, 1983, pp. 412-417. doi:10.1248/jhs1956.29.6_412

[24]   K. Kuwayama, K. Tsujikawa, H. Miyaguchi, T. Kanamori, Y. T. Iwata and H. Inoue, “Interaction of 3,4-Methylenedioxymethamphetamine and Methamphetamine during Metabolism by in Vitro Human Metabolic Enzymes and in Rats,” Journal of Forensic Sciences, Vol. 57, No. 4, 2011, pp. 1008-1013. doi:10.1111/j.1556-4029.2011.02039.x

[25]   L. Y. Lin, E. W. Di Stefano, D. A. Schmitz, L. Hsu, S. W. Ellis, M. S. Lennard, G. T. Tucker and A. K. Cho, “Oxidation of Methamphetamine and Methylenedioxymethamphetamine by CYP2D6,” Drug Metabolism and Disposition, Vol. 25, No. 9, 1997, pp. 1059-1064.