Basic information Indications and Usage Mechanisms of Action Pharmacokinetics Adverse reactions Contradictions Warnings and Precautions Safety Supplier Related
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Oxytocin is also called Pitocin, is a kind of uterine contraction medicine, can be extracted from animal posterior pituitary or chemical synthesis, chemical synthesis including on vasopressin, no booster effect, selective excitate uterine smooth muscle, strengthen its contracting, uterus is most sensitive to oxytocin (estrogen secretion increase) when parturient , immature uterus have no reactivity to this product, pregnancy early or middle uterine have low reactivity to oxytocin, late pregnancy is gradually increased, and before the antepartum, the reactivity is the highest.

Basic information Indications and Usage Mechanisms of Action Pharmacokinetics Adverse reactions Contradictions Warnings and Precautions Safety Supplier Related

Oxytocin Basic information

Product Name:
  • (1-hemicystine)-oxytocin
  • 3-isoleucine-8-leucinevasopressin
  • atonino
  • cyclic(1-6)-di///
  • di-sipidin
  • endopituitrina
  • glycinamide,l-cysteinyl-l-tyrosyl-l-isoleucyl-l-glutaminyl-l-asparaginyl-l-cys
  • nobitocins
Product Categories:
  • Amino Acid Derivatives
  • Organics
  • Amino Acids 13C, 2H, 15N
  • Peptide
  • Amino Acids & Derivatives
  • Intermediates & Fine Chemicals
  • Pharmaceuticals
  • Vasopressin and Oxytocin receptor
  • Peptide Receptors
  • hormones
  • peptides for birth-giving use
  • Veterinary drugs
Mol File:

Oxytocin Chemical Properties

Melting point:
D22 -26.2° (c = 0.53)
1.1086 (rough estimate)
refractive index 
1.6700 (estimate)
storage temp. 
Very soluble in water. It dissolves in dilute solutions of acetic acid and of ethanol (96 per cent).
lyophilized powder
pKa ~6.1(free amino group on Cys) (Occasionally);~10(free phenol on Tyr) (Occasionally)
Water Solubility 
Soluble in water.
CAS DataBase Reference
50-56-6(CAS DataBase Reference)

Safety Information

Hazard Codes 
Risk Statements 
Safety Statements 
WGK Germany 
HS Code 
Hazardous Substances Data
50-56-6(Hazardous Substances Data)
LD50 oral in rat: > 20520ug/kg



Oxytocin Usage And Synthesis

Indications and Usage

Oxytocin (OT) is a type of uterine contraction drug and can be derived from the animal posterior pituitary or chemically synthesized.
Oxytocin is a uterine contraction drug that is mostly used in late pregnancy induction and stagnant birth due to weak uterine contractions. Suitable for inducing labor and alleviating pain. Commonly used with ergot preparations to be used in inducing labor, expediting labor, and in uterine bleeding due to weak uterine contractions following birth or still birth. Nose drops can be used to promote lactation.

Mechanisms of Action

Oxytocin does not contain vasopressin and has no pressure-boosting effects. It can be absorbed through oral mucosa, selectively excite smooth uterine muscle, and intensify its contractions. The uterus is most sensitive to oxytocin when in labor (due to increased estrogen secretion), and an immature uterus will not respond to this drug. During early or mid-term pregnancy, the uterus has a relatively low reactivity to oxytocin, which gradually increases during late-stage pregnancy and peaks during labor. Small doses can strengthen the rhythmic contractions of smooth uterine muscles, increase their contractibility, increase their contraction speed, ensure similar contraction characteristics to that of a natural birth, and maintain polarity and symmetry. Thus, it is used clinically to expedite and induce labor. Large doses cause tonic contractions in the uterine muscles, so it is used clinically to burst blood vessels between muscle fibers, prevent postpartum hemorrhage, and ensuring postpartum recovery. It can also promote lactation by causing the breast ducts to contract and expel milk from the breasts, but it cannot increase the lactation amount.


Ineffective when taken orally, as it can be damaged by digestive fluids, although it can be absorbed through oral mucosa. 1-3 minutes of venous infusion 0.01 IU can induce physiological uterine contractions (Rhythmic, polar, symmetrical) with a short time span, as its half-life is only 2.5-3 minutes. Large doses cause tonic uterine contractions.

Adverse reactions

Oxytocin derived from cow or pig’s pituitary occasionally causes allergic reactions, and infusing too quickly may lead to mild vasodilation and hypotension. Patients who suffer from abruptio placentae, heart disease, or enlarged uterus, are over 35 years old, have a history of cesarean section or uterine muscle tumor removal, or are experiencing a breech birth should use with caution. Using oxytocin while experiencing a sacral block may lead to severe hypertension and even cerebrovascular rupturing. Cannot be injected in the same solution with norepinephrine. Incompatible with hydrolyzed proteins.


Do not use during birth if there are obvious signs of an unsymmetrical head, incorrect fetal position, exposed umbilical cord, prolapse, complete placenta previa, narrow pelvis, or overly intense uterine contractions. Not to be used by patients with overly narrow pelvises, histories of uterine surgery (including C-sections), excessive pains, blocked birth canals, abruptio placentae, or pregnancy poisoning.

Warnings and Precautions

Dosage and infusion speed must be strictly monitored when used to expedite or induce labor to prevent tonic contractions, which can suffocate the fetus or rupture the uterus.

Chemical Properties

White Solid




Oxytocin is the principal uterus-contracting and lactation-stimulating hormone of the posterior pituitary gland.


Oxytocin is a nonapeptide hormone primarily synthesized in magnocellular neurons of the paraventricular and supraoptic nuclei of the hypothalamus. It is known best for its role in stimulating uterine contraction and lactation and is important for social memory and attachment, sexual and maternal behavior, and aggression. Also, it has been implicated in various non-social behaviors, including learning, anxiety, feeding, and pain perception.


ChEBI: A cyclic nonapeptide hormone with amino acid sequence CYIQNCPLG that also acts as a neurotransmitter in the brain; the principal uterine-contracting and milk-ejecting hormone of the posterior pituitary. Together with the neuropeptide vasopressin, it is bel eved to influence social cognition and behaviour.

Manufacturing Process

BocGly resin (3.0 g, 3 meq) was placed in the reaction vessel of a Vega Model 50 semiautomatic peptide synthesizer.Activation of the amino acid was carried out by dissolving 10 meq of a suitably protected amino acid, 15 meq of hydroxy benzotriazole and 10 meq of dicyclohexylcarbodiimide in DMF (70 ml), whereupon the mixture was left at room temperature for 1 h (asparagine and glutamine were activated at 0°C for 15 min), whereupon the precipitate was filtered off, and the filtrate was treated the activated amino acid in Table 1 (step 7). The completion of the coupling step was checked by the method of Kaiser (Anal. Biochem. 34, 595 (1970)) after the cycle had been completed (step 9). If the test was positive (coupling yield below 99%), the cycle was repeated starting from step 7. If the test was negative, the termination procedure was performed according to Table 2. When the whole sequence had been coupled, the resin was placed on a filter and washed repeatedly with methanol. The dried product was placed in a glass vessel and cooled in an ethanol-dry ice bath and suspended in methanol (about 100 ml). The mixture was then saturated with sodium-dried ammonia to achieve approximately 50% concentration. Then the vessel was placed in a steel cylinder and left at room temperature for two days. After the pressure had been relieved, the product was filtered, and the residue was extracted with hot (about 100°C) DMF (2x100 ml). The filtrate and the extract were combined and evaporated. The residue was dissolved in a small amount of hot DMF, and methanol was added to the coupling point. The precipitate was collected by filtration and washed on the filter with methanol. After drying in vacuum, the purity was checked by thin-layer chromatography. Yield about 2.8 g.
100 mg of the above described protected peptide were placed in a 100 ml round-bottom flask, and dry nitrogen was flushed through for about 15 min. 50 ml of sodium-dried ammonia were distilled in, and the protective group was removed from the product by adding sodium until blue color remained in the solution for 15 sec. The excess of sodium was destroyed by adding of ammonium chloride. Ammonia was removed in a nitrogen stream, and the residue was dissolved in 1 liter of methanol. The pH of the solution was adjusted to about 4 with concentrated acetic acid, and the solution was then titrated with 0.1 mM of iodine in methanol to brownish color. The mixture was stirred with 3 g of Dowex 50x2 ion exchanger in chloride form for 10 min at room temperature. The ion exchanger was removed by filtration, and the filtrate was evaporated to dryness. The residue was dissolved in 3 ml of 20% acetic acid and purified by chromatography on Sephadex G-25 with 20% acetic acid as eluent. The final purification was achieved by reverse phase HPLC. The purity of the product was determined on a HPCL column μ- Bondapak C-18 in 45% ethanol and 55% 5 mM trifluoroacetic acid in water. The column was supplied by Water Associates, Inc., Millford, Mass., U.S.A. The purity of the product was also shown by amino acid analysis.

brand name

Pitocin (Parkdale); Syntocinon (Novartis);Oxytocin;Pituitrin.

Therapeutic Function


Health Hazard

Uterine contraction, milk ejection, facilitates sperm ascent in female tract
Decreases membrane potential of myometrium, basic metabolic rate, and liver glycogen
Stimulates oviposition in hen, releases luteinizing hormone (LH)
Increases blood sugar and urinary sodium and potassium

Safety Profile

Poison by intravenous route. Experimental reproductive effects. A pituitary hormone which stimulates uterine contraction and milk production. The principal uterus-contracting and lactation-stimulating hormone of the posterior pituitary gland.Note: Unlike

Veterinary Drugs and Treatments

In veterinary medicine, oxytocin has been used for induction or enhancement of uterine contractions at parturition, treatment of postpartum retained placenta and metritis, uterine involution after manual correction of prolapsed uterus in dogs, and in treating agalactia.

Purification Methods

It is a cyclic nonapeptide which is purified by countercurrent distribution between solvent and buffer. It is soluble in H2O, n-BuOH and isoBuOH. [Bodanszky & du Vigneaud J Am Chem Soc 81 2504 1959, Cash et al. J Med Pharm Chem 5 413 1962, Sakakibara et al. Bull Chem Soc Jpn 38 120 1965; solid phase synthesis: Bayer & Hagenmyer Tetrahedron Lett 2037 1968.] It was also synthesised on a solid phase matrix and finally purified as follows: A Sephadex G-25 column is equilibrated with the aqueous phase of a mixture of 3.5% AcOH (containing 1.5% of pyridine)/n-BuOH/*C6H6 (2:1:1) and then the organic phase of this mixture is run through. A solution of oxytocin (100mg) in H2O (2mL) is applied to the column which is then eluted with the organic layer of the above mixture. The fractions containing the major peak [as determined by the Folin-Lowry protein assay: Fryer et al. Anal Biochem 153 262 1986] are pooled, diluted with twice their volume of H2O, evaporated to a small volume and lyophilised to give oxytocin as a pure white powder (20mg, 508 U/mg). [Ives Can J Chem 46 2318 1968, Beilstein 22 III/IV 82.]


Shenzhen JYMed Technology Co., Ltd. Gold
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Product Name:oxytocin
Purity:98% Package:1G/1.00; Remarks:20000g
Hangzhou Peptide Biochem Co.,Ltd Gold
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Product Name:Oxytocin Acetate
Purity:98.5% Package:1g,10g,25g,100g Remarks:USP,EP
Chengdu Youngshe Chemical Co., Ltd. Gold
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Product Name:Oxytocin
Purity:>95% Package:1g; 10g; 100g
Shanghai Chengyu Biotechnology Co., Ltd. Gold
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Product Name:Oxytocin
Purity:EP/BP/USP Package:1G;10G;100G;1KG Remarks:1
Hangzhou Guangyuan Biotechnologies Co.,LTD Gold
Products Intro
Product Name:Oxytocin
Purity:98% HPLC Package:5mg;10mg;50mg;100mg