Chemical Name：Oxytocin
Synonyms:α-Hypophamine; Pitocin (synthetic form)
Molecular Formula:C₄₃H₆₆N₁₂O₁₂S₂
Molecular Weight:1007.19 g/mol
CAS Number:50-56-6
Appearance:White crystalline powder
Solubility:Soluble in water, acetic acid; insoluble in ether, petroleum ether
Stability:Sensitive to light, heat, and oxidation; unstable in strong acids/bases
Storage:Conditions 2–8°C (refrigerated), protected from light
Biological Role:Neuropeptide hormone acting as a neurotransmitter and neuromodulator
Primary Functions:Stimulates uterine contractions (childbirth), milk ejection, and social bonding (e.g., trust, pair attachment)
Synthesis Produced in the hypothalamus, secreted by the posterior pituitary gland
Half-life:1–6 minutes (rapid degradation in blood)
Chemical Structure Cyclic nonapeptide (9 amino acids): Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂ (disulfide bond between Cys1 and Cys6)
Oxytocin is a peptide hormone and neurotransmitter primarily known for its roles in childbirth (inducing labor) and lactation (milk let-down). It also influences social behaviors, including bonding, trust, and emotional attachment in mammals. Synthetically produced as Pitocin, it is used medically to manage labor or postpartum hemorrhage. Its rapid degradation necessitates intravenous administration for clinical use.
| Parameter | Specification | Test Method | Acceptance Criteria |
|---|
| Appearance | White or almost white crystalline powder | Visual inspection | Complies with description |
| Identification |
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| - HPLC | Retention time matches reference standard | USP/EP Chromatography | Conforms to standard |
| - FT-IR | Spectrum matches reference | Infrared spectroscopy | Peak consistency ≥95% |
| Purity (HPLC) | ≥98.5% | USP/EP Chromatography | 98.5–101.0% |
| Water Content | ≤5.0% | Karl Fischer titration | ≤5.0% w/w |
| Residue on Ignition | ≤1.0% | USP <281> | ≤1.0% |
| Heavy Metals | ≤20 ppm | ICP-MS/AAS | ≤20 ppm |
| Bacterial Endotoxins | ≤5.0 IU/mg | LAL test (USP <85>) | ≤5.0 IU/mg |
| Microbial Limits |
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|
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| - Total Aerobic Count | ≤100 CFU/g | USP <61> | ≤100 CFU/g |
| - Yeast/Mold | ≤50 CFU/g | USP <61> | ≤50 CFU/g |
| Assay (Potency) | 95.0–105.0% of labeled potency | Bioassay/HPLC | Within range |
| Sterility (if applicable) | Sterile | USP <71> | No growth observed |
| pH (Solution) | 3.0–5.0 (for injections) | Potentiometric method | 3.0–5.0 |
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