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Oxytocin

Athanor · official

C43H66N12O12S2 · 1007.2 g/mol

IUPAC name: (2S)-1-[(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-[(4-hydroxyphenyl)methyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl]-N-[(2S)-1-[(2-amino-2-oxoethyl)amino]-4-methyl-1-oxopentan-2-yl]pyrrolidine-2-carboxamide

Also called Pitocin, OT, love hormone, posterior pituitary hormone, uterotonic, 9-residue peptide

Hormones
Open in Athanor
The structure of Oxytocin
Drawn from its SMILES with RDKit
Harmful or irritantHealth hazardWarningHarmful if swallowed · Suspected of damaging fertility or the unborn child

Names and identifiers

IUPAC name
(2S)-1-[(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-[(4-hydroxyphenyl)methyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl]-N-[(2S)-1-[(2-amino-2-oxoethyl)amino]-4-methyl-1-oxopentan-2-yl]pyrrolidine-2-carboxamide
Synonyms
Pitocin, OT, love hormone
+ 40 more

posterior pituitary hormone, uterotonic, 9-residue peptide, Endopituitrina, Ocytocin, Syntocinon, Oxytocinum, Orasthin, Oxitocina, Oxystin, Oxytocine, Synthetic oxytocin, Piton S, (1-Hemicystine)oxytocin, Syntocinone, Presoxin, Syntocin, Uteracon, Di-sipidin, Nobitocin S, 3-Isoleucine-8-leucine vasopressin, Atonin O, alpha-Hypophamine, Intertocine S, DTXSID8048361, (2S)-1-[(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-[(4-hydroxyphenyl)methyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl]-N-[(2S)-1-[(2-amino-2-oxoethyl)amino]-4-methyl-1-oxopentan-2-yl]pyrrolidine-2-carboxamide, 1JQS135EYN, Vasopressin, 3-L-isoleucine-8-L-leucine-, CHEBI:7872, OXYTOCIN 5 USP UNITS IN DEXTROSE 5%, OXYTOCIN 10 USP UNITS IN DEXTROSE 5%, OXYTOCIN 20 USP UNITS IN DEXTROSE 5%, TNX1900, TTA-121, TNX-1900, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2, cyclic 1-6 disulfide, L-Cysteinyl-L-tyrosyl-L-isoleucyl-L-glutaminyl-L-asparaginyl-L-cysteinyl-L-prolyl-L-leucylglycinamide cyclic (1-6)-disulfide, 1-({(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-16-(4-hydroxybenzyl)-13-[(1S)-1-methylpropyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentaazacycloicosan-4-yl}carbonyl)-L-prolyl-L-leucylglycinamide, Oxytocin Injectable, (2S)-1-((4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-((2S)-butan-2-yl)-16-((4-hydroxyphenyl)methyl)-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl)-N-((2S)-1-((2-amino-2-oxoethyl)amino)-4-methyl-1-oxopentan-2-yl)pyrrolidine-2-carboxamide

Molecular formula
C43H66N12O12S2
Empirical formula
C43H66N12O12S2
Molecular weight
1007.2 g/mol
Exact mass
1006.43646
CAS number
50-56-6
PubChem CID
439302
Canonical SMILES
CCC(C)C1C(=O)NC(C(=O)NC(C(=O)NC(CSSCC(C(=O)NC(C(=O)N1)CC2=CC=C(C=C2)O)N)C(=O)N3CCCC3C(=O)NC(CC(C)C)C(=O)NCC(=O)N)CC(=O)N)CCC(=O)N
Isomeric SMILES
CC[C@H](C)[C@H]1C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@@H](CSSC[C@@H](C(=O)N[C@H](C(=O)N1)CC2=CC=C(C=C2)O)N)C(=O)N3CCC[C@H]3C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N)CC(=O)N)CCC(=O)N
InChI
InChI=1S/C43H66N12O12S2/c1-5-22(4)35-42(66)49-26(12-13-32(45)57)38(62)51-29(17-33(46)58)39(63)53-30(20-69-68-19-25(44)36(60)50-28(40(64)54-35)16-23-8-10-24(56)11-9-23)43(67)55-14-6-7-31(55)41(65)52-27(15-21(2)3)37(61)48-18-34(47)59/h8-11,21-22,25-31,35,56H,5-7,12-20,44H2,1-4H3,(H2,45,57)(H2,46,58)(H2,47,59)(H,48,61)(H,49,66)(H,50,60)(H,51,62)(H,52,65)(H,53,63)(H,54,64)/t22-,25-,26-,27-,28-,29-,30-,31-,35-/m0/s1
InChIKey
XNOPRXBHLZRZKH-DSZYJQQASA-N
Molfile

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

Calculated

Heavy atoms
69
Rings
3
Aromatic rings
1
Fraction sp³ carbons (Fsp3)
0.6
H-bond donors
12
H-bond acceptors
15
Rotatable bonds
17
TPSA (Ų)
399.5 computed here · PubChem 450
Formal charge
0
XLogP3
-2.6 PubChem
Complexity
1870 PubChem
Stereocenters
9 definedCIP: C2: R · C8: S · C20: S · C21: S · C28: S · C37: S · C45: R · C54: S · C58: S
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

  • C51.28%
  • H6.61%
  • N16.69%
  • O19.06%
  • S6.37%

Isotope pattern

100%1006.43754%1007.43926%1008.4388.6%1009.4392.4%1010.4391011.4401012.441

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
-3.61 Crippen (Wildman and Crippen 1999)
log S (water solubility)
-2.75 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
5.97 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 1007.21
  • log P ≤ 5 (Crippen): -3.61
  • H-bond donors ≤ 5: 12
  • H-bond acceptors ≤ 10: 15

Breaks 3 of the 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

Warning

Most widely reported: 49 company reports to ECHA. Source [2].

  • Harmful or irritant
  • Health hazard
  • H302Harmful if swallowed (10.2% of reports)
  • H361Suspected of damaging fertility or the unborn child (14.3% of reports)

Precautionary statements: P203, P264, P270, P280, P301+P317, P318, P330, P405, P501

View all classifications (2)
  • [2] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 79.6% (39 of 49) of all reports.
  • [2] European Chemicals Agency (ECHA) · 49 reports · WarningH302, H361

Storage

  • Store in tight container as defined in the usp-nf. This material should be handled and stored per label instructions to ensure product integrity.[1]
  • Oxytocin injection should be stored at temperatures less than 15-25 °C but should not be frozen. Pitocin should be refrigerated at 2-8 °C but may be exposed to temperatures ranging from 15-25 °C for up to 30 days; Pitocin exposed to this latter temperature range for longer periods should be discarded.[1]

Incompatibilities

  • Oxytocin injection appears to be compatible with most iv infusion fluids but is reported to be physically incompatible with fibrinolysin, norepinephrine bitartrate, prochlorperazine edisylate, and warfarin sodium. Oxytocin injection has also been reported to be incompatible with various other drugs, but the compatibility depends on several factors (eg, the concentration of the drugs, resulting pH, temperature). Specialized references should be consulted for more specific compatibility information.[1]

Safety data sheets on the supplier’s page: AppChem, Combi-Blocks, Alfa Chemistry.

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

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

  1. [1]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
  2. [2]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
  3. ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
  4. ·Literature on PubChem

Data last updated 2026-10-14.