Indomethacin

Athanor · official

C₁₉H₁₆ClNO₄ · 357.8 g/mol

IUPAC name: 2-[1-(4-chlorobenzoyl)-5-methoxy-2-methylindol-3-yl]acetic acid

Also called indometacin, Indocin, NSAID

Drugs Rings

Open in Athanor

Drawn from its SMILES with RDKit

DangerFatal if swallowed · Toxic if swallowed · May cause an allergic skin reaction · Causes serious eye damage · May cause respiratory irritation · May cause drowsiness or dizziness · May damage fertility or the unborn child · May causes damage to organs through prolonged or repeated exposure · May cause long lasting harmful effects to aquatic life

Names and identifiers

IUPAC name: 2-[1-(4-chlorobenzoyl)-5-methoxy-2-methylindol-3-yl]acetic acid
Synonyms: indometacin, Indocin, NSAID
+ 37 more
Indomethacine, Indometacine, Indocid, Metindol, Reumacide, Indomethazine, Idomethine, Imbrilon, Mikametan, Indacin, Mobilan, Tannex, Amuno, Inteban sp, Artrinovo, Confortid, Indomecol, Indomethacinum, Metartril, Methazine, Artracin, Artrivia, Dolovin, Indomed, Indomee, Indoptic, Indoptol, Inflazon, Infrocin, Metacen, Mezolin, Sadoreum, Inacid, Lausit, Indo-rectolmin, Indo-tablinen, Indometacyna
Molecular formula: C₁₉H₁₆ClNO₄
Empirical formula: C₁₉H₁₆ClNO₄
Molecular weight: 357.8 g/mol
Exact mass: 357.07679
CAS number: 53-86-1
PubChem CID: 3715
Canonical SMILES: CC1=C(C2=C(N1C(=O)C3=CC=C(C=C3)Cl)C=CC(=C2)OC)CC(=O)O
Isomeric SMILES: CC1=C(C2=C(N1C(=O)C3=CC=C(C=C3)Cl)C=CC(=C2)OC)CC(=O)O
InChI: InChI=1S/C19H16ClNO4/c1-11-15(10-18(22)23)16-9-14(25-2)7-8-17(16)21(11)19(24)12-3-5-13(20)6-4-12/h3-9H,10H2,1-2H3,(H,22,23)
InChIKey: CGIGDMFJXJATDK-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Pale-yellow to yellow-tan, crystalline powder[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Crystals. (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown Pale-yellow to yellow-tan, crystalline powder [2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1058
Odor: Odorless, or has slight odor[2]
Melting point: Reported, but no value passed the checks.
The value and why
311 or 323.6 °F (NTP, 1992) (could not be read; source [1])
Solubility in water: In water, 0.937 mg/L at 25 °C[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
–shown In water, 0.937 mg/L at 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; Aquasol Database of Aqueous Solubility. Version 5. College of Pharmacy, University of Arizona-Tucson, AZ. PC Version. (1992)
– 1 g in about 30 mL chloroform [2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1058
log P: 4.27 at pH 2.0[2]
2 values
Only one source reports it.
Value As written Source
– log Kow = 0.91 at pH 7.4 [2] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161
–shown 4.27 at pH 2.0 [2] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161

Value	As written	Source
–	Crystals. (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown	Pale-yellow to yellow-tan, crystalline powder	[2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1058

Value	As written	Source
–shown	In water, 0.937 mg/L at 25 °C	[2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; Aquasol Database of Aqueous Solubility. Version 5. College of Pharmacy, University of Arizona-Tucson, AZ. PC Version. (1992)
–	1 g in about 30 mL chloroform	[2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1058

Value	As written	Source
–	log Kow = 0.91 at pH 7.4	[2] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161
–shown	4.27 at pH 2.0	[2] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 25
Rings: 3
Aromatic rings: 3
Fraction sp³ carbons (Fsp3): 0.16
H-bond donors: 1
H-bond acceptors: 3 computed here · PubChem 4
Rotatable bonds: 4
TPSA (Å²): 68.5
Formal charge: 0
XLogP3: 4.3 PubChem
Complexity: 506 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C63.78%
H4.51%
Cl9.91%
N3.91%
O17.89%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 3.93 Crippen (Wildman and Crippen 1999)
log S (water solubility): -4.71 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.08 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 357.79
log P ≤ 5 (Crippen): 3.93
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 3

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Most widely reported: 189 company reports to ECHA. Source [3].

Corrosive
Acute toxicity
Harmful or irritant
Health hazard

H300Fatal if swallowed (81% of reports)
H301Toxic if swallowed (19% of reports)
H317May cause an allergic skin reaction (24.9% of reports)
H318Causes serious eye damage (18.5% of reports)
H335May cause respiratory irritation (18.5% of reports)
H336May cause drowsiness or dizziness (18.5% of reports)
H360May damage fertility or the unborn child (25.4% of reports)
H373May causes damage to organs through prolonged or repeated exposure (19% of reports)
H413May cause long lasting harmful effects to aquatic life (19% of reports)

Precautionary statements: P203, P260, P261, P264, P264+P265, P270, P271, P272, P273, P280, P301+P316, P302+P352, P304+P340, P305+P354+P338, P317, P318, P319, P321, P330, P333+P317, P362+P364, P403+P233, P405, P501

View all classifications (2)

[3] European Chemicals Agency (ECHA) · 189 reports · DangerH300, H301, H317, H318, H335, H336, H360, H373, H413
[2] Hazardous Substances Data Bank (HSDB) · DangerH300

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]

Storage

Keep container tightly closed in a dry and well-ventilated place. Keep in a dry place.[2]
Indomethacin capsules should be stored in well-closed containers at a temperature less than 40 °C, preferably at 15 to 30 °C. Indomethacin oral suspension should be stored in tight, light-resistant containers at a temperature less than 30 °C; exposure to temperatures greater than 50 °C should be avoided, and the suspension should be protected from freezing. Indomethacin suppositories should be stored at a temperature less than 30 °C; exposure to temperatures greater than 40 °C (even transiently) should be avoided.[2]

Incompatibilities

Incompatible materials: Strong bases[2]

Safety data sheets on the supplier’s page: Debye Scientific Co., Ltd, AppChem, Midas Pharma GmbH.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[4]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[5]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[6]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[8]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[9]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.