Methylphenidate is stereoselectively hydrolyzed by human carboxylesterase CES1A1

Zejin Sun, Daryl J. Murry, Sonal P. Sanghani, Wilhelmina I. Davis, Natalia Y. Kedishvili, Qin Zou, Thomas D. Hurley, William F. Bosron

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Abstract

Methylphenidate is an important stimulant prescribed to treat attention-deficit hyperactivity disorder. It has two chiral centers, but most current commercial formulations consist of the racemic mixture of the threo pair of methylphenidate isomers (d-, l-threo-methylphenidate). The d-isomer is the pharmacologically active component. Numerous studies reported that oral administration of the methylphenidate racemate undergoes first-pass, stereoselective clearance in humans with l-methylphenidate being eliminated faster than d-methylphenidate. Accordingly, the kinetics of hydrolysis of individual enantiomers by purified native and recombinant human liver carboxylesterases CES1A1 and CES2 and a colon isoenzyme CES3 were examined with a liquid chromatography/mass spectrometry assay. The expression of CES1A1, CES2, and CES3 in Sf9 cells and the methods for purification of the three isoenzymes are reported. CES1A1 has a high catalytic efficiency for both d- and l-enantiomers of methylphenidate. No catalytic activity was detected with CES2 and CES3 for either enantiomer. The catalytic efficiency of CES1A1 for l-methylphenidate (kcat/Km = 7.7 mM-1 min -1) is greater than that of d-methylphenidate (kcat/K m = 1.3-2.1 mM-1 min-1). Hence, the catalytic efficiency of CES1A1 for methylphenidate enantiomers agrees with stereoselective clearance of methylphenidate reported in human subjects. Both enantiomers of methylphenidate can be fit into the three-dimensional model of CES1A1 to form productive complexes in the active site. We conclude that CES1A1 is the major enzyme responsible for the first-pass, stereoselective metabolism of methylphenidate.

Original languageEnglish (US)
Pages (from-to)469-476
Number of pages8
JournalJournal of Pharmacology and Experimental Therapeutics
Volume310
Issue number2
DOIs
StatePublished - Aug 1 2004

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ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this

Sun, Z., Murry, D. J., Sanghani, S. P., Davis, W. I., Kedishvili, N. Y., Zou, Q., Hurley, T. D., & Bosron, W. F. (2004). Methylphenidate is stereoselectively hydrolyzed by human carboxylesterase CES1A1. Journal of Pharmacology and Experimental Therapeutics, 310(2), 469-476. https://doi.org/10.1124/jpet.104.067116