Article · Wikipedia archive · Last revised Jul 20, 2026

Modafinil acid

Modafinil acid (code name CRL-40467), also known as modafinilic acid or modafinil carboxylate, is one of the two major metabolites of modafinil – the other being modafinil sulfone. Modafinil acid is also a metabolite of the modafinil prodrug, adrafinil, and the (R)-(–)-enantiomer is a metabolite of armodafinil, the (R)-(–)-enantiomer of modafinil. Between 30 - 60% of modafinil is converted to modafinil acid and its half life is roughly half that of modafinil (about 7 hours). Modafinil acid seems to be inactive, and similarly to modafinil sulfone, does not appear to contribute to the wakefulness-promoting/psychostimulant effects of modafinil.

Last revised
Jul 20, 2026
Read time
≈ 2 min
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Citations
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Wikipedia ↗
Modafinil acid
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Names
Preferred IUPAC name
(Diphenylmethanesulfinyl)acetic acid
Other names
Modafinilic acid; Modafinil carboxylate; CRL-40467
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.219.633
UNII
  • InChI=1S/C15H14O3S/c16-14(17)11-19(18)15(12-7-3-1-4-8-12)13-9-5-2-6-10-13/h1-10,15H,11H2,(H,16,17)
    Key: QARQPIWTMBRJFX-UHFFFAOYSA-N
  • C1=CC=C(C=C1)C(C2=CC=CC=C2)S(=O)CC(=O)O
Properties
C15H14O3S
Molar mass 274.33 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Modafinil acid (code name CRL-40467), also known as modafinilic acid or modafinil carboxylate, is one of the two major metabolites of modafinil – the other being modafinil sulfone.1 Modafinil acid is also a metabolite of the modafinil prodrug, adrafinil, and the (R)-(–)-enantiomer is a metabolite of armodafinil, the (R)-(–)-enantiomer of modafinil.2 Between 30 - 60% of modafinil is converted to modafinil acid and its half life is roughly half that of modafinil (about 7 hours).3 Modafinil acid seems to be inactive,4 and similarly to modafinil sulfone, does not appear to contribute to the wakefulness-promoting/psychostimulant effects of modafinil.567

In the breakdown process of modafinil, modafinil is primarily hydrolyzed by an esterase or amidase enzyme into modafinil acid.8 The apparent clearance of modafinil acid is significantly higher than that of modafinil, following the hypothesis that metabolism increases the polarity and the clearance of modafinil.

See also

See also

References

References

  1. Dubey S, Ahi S, Reddy IM, Kaur T, Beotra A, Jain S (December 2009). "A novel study of screening and confirmation of modafinil, adrafinil and their metabolite modafinilic acid under EI-GC-MS and ESI-LC-MS-MS ionization". Indian Journal of Pharmacology. 41 (6): 278–283. doi:10.4103/0253-7613.59928. PMC 2846503. PMID 20407560.
  2. Sousa A, Dinis-Oliveira RJ (2020). "Pharmacokinetic and pharmacodynamic of the cognitive enhancer modafinil: Relevant clinical and forensic aspects". Substance Abuse. 41 (2): 155–173. doi:10.1080/08897077.2019.1700584. PMID 31951804. S2CID 210709160.
  3. Wong YN, King SP, Simcoe D, Gorman S, Laughton W, McCormick GC, Grebow P (March 1999). "Open-label, single-dose pharmacokinetic study of modafinil tablets: influence of age and gender in normal subjects". Journal of Clinical Pharmacology. 39 (3): 281–288. doi:10.1177/009127009903900312. PMID 10073328. S2CID 30258993.
  4. Wong YN, Wang L, Hartman L, Simcoe D, Chen Y, Laughton W, et al. (October 1998). "Comparison of the single-dose pharmacokinetics and tolerability of modafinil and dextroamphetamine administered alone or in combination in healthy male volunteers". Journal of Clinical Pharmacology. 38 (10): 971–978. doi:10.1002/j.1552-4604.1998.tb04395.x. PMID 9807980. S2CID 32857213.
  5. Schwertner HA, Kong SB (March 2005). "Determination of modafinil in plasma and urine by reversed phase high-performance liquid-chromatography". Journal of Pharmaceutical and Biomedical Analysis. 37 (3): 475–479. doi:10.1016/j.jpba.2004.11.014. PMID 15740906.
  6. Robertson P, Hellriegel ET (2003). "Clinical pharmacokinetic profile of modafinil". Clinical Pharmacokinetics. 42 (2): 123–137. doi:10.2165/00003088-200342020-00002. PMID 12537513. S2CID 1266677.
  7. Robertson P, Hellriegel ET, Arora S, Nelson M (January 2002). "Effect of modafinil on the pharmacokinetics of ethinyl estradiol and triazolam in healthy volunteers". Clinical Pharmacology and Therapeutics. 71 (1): 46–56. doi:10.1067/mcp.2002.121217. PMID 11823757. S2CID 21552865.
  8. Wu KH, Guo T, Deng CH, Guan Z, Li L, Zhou TY, Lu W (November 2012). "Population pharmacokinetics of modafinil acid and estimation of the metabolic conversion of modafinil into modafinil acid in 5 major ethnic groups of China". Acta Pharmacologica Sinica. 33 (11): 1401–1408. doi:10.1038/aps.2012.124. PMC 4011351. PMID 23103618.