Blog / Post / Oxytocin Quality Standard EP 8.0 Zhejiang Peptides Biotech Co|Peptide synthsis China|cosmetic peptide synthesis|GMP peptide modifcation

Cas [50-56-6] DEFINITION L-Cysteinyl-L-tyrosyl-L-isoleucyl-L-glutamyl-L-asparaginyl-Lcysteinyl-L-prolyl-L-leucylglycinamide cyclic (1→6)-disulfide. Synthetic cyclic nonapeptide having the structure of thehormone produced by the posterior lobe of the pituitary glandthat stimulates contraction of the uterus and milk ejection inreceptive mammals. It is available in the freeze-dried formas an acetate. Content: 93.0 per cent to 102.0 per cent (anhydrous and aceticacid-free substance).By convention, for the purpose of labelling oxytocinpreparations, 1 mg of oxytocin peptide (C43H66N12O12S2) isequivalent to 600 IU of biological activity. CHARACTERS Appearance: white or almost white, hygroscopic powder. Solubility: very soluble in water. It dissolves in dilute solutionsof acetic acid and of ethanol (96 per cent). IDENTIFICATION A. Examine the chromatograms obtained in the assay. Results: the principal peak in the chromatogram obtainedwith the test solution is similar in retention time to the principal peak in the chromatogram obtained with the reference solution. B. Amino acid analysis (2.2.56). For hydrolysis use Method 1 and for analysis use Method 1. Express the content of each amino acid in moles. Calculate the relative proportions of the amino acids, taking 1/6 of the sum of the number of moles of aspartic acid, glutamic acid, proline, glycine, isoleucine and leucine as equal to 1.The values fall within the following limits: aspartic acid: 0.90 to 1.10; glutamic acid: 0.90 to 1.10; proline: 0.90 to1.10; glycine: 0.90 to 1.10; leucine: 0.90 to 1.10; isoleucine:0.90 to 1.10; tyrosine: 0.7 to 1.05; half-cystine: 1.4 to 2.1. Not more than traces of other amino acids are present. TESTS pH (2.2.3): 3.0 to 6.0. Dissolve 0.200 g in carbon dioxide-free water R and dilute to 10.0 mL with the same solvent. Related substances. Liquid chromatography (2.2.29): use the normalisation procedure. Test solution. Prepare a 0.25mg/mL solution of the substance to be examined in a 15.6 g/L solution of sodium dihydrogen phosphate R. Resolution solution. Dissolve the contents of a vial of oxytocin/desmopressin validation mixture CRS in 1 mL of a 15.6 g/L solution of sodium dihydrogen phosphate R. Column: – size: l = 0.125 m, ? = 4.6 mm; – stationary phase: octadecylsilyl silica gel for chromatography R (5 μm). Mobile phase: – mobile phase A: 15.6 g/L solution of sodium dihydrogen phosphate R; – mobile phase B: acetonitrile for chromatography R, water R (50:50 V/V); Time(min) Mobile phase A (per cent V/V) Mobile phase B (per cent V/V) 0 - 30 70 → 40 30 → 60 30 - 30.1 40 → 70 60 → 30 30.1 - 45 70 30 Flow rate: 1 mL/min. Detection: spectrophotometer at 220 nm. Injection: 50 μL. Retention time: oxytocin = about 7.5 min; desmopressin = about 10min. – resolution: minimum 5.0 between the peaks due to desmopressin and oxytocin. Limits: – any impurity: maximum 1.5 per cent; – total: maximum5 per cent; – disregard limit: 0.1 per cent. Acetic acid (2.5.34): 6.0 per cent to 10.0 per cent. Test solution. Dissolve 15.0 mg of the substance to be examined in a mixture of 5 volumes of mobile phase B and 95 volumes of mobile phase A and dilute to 10.0 mL with the same mixture of mobile phases. Water (2.5.12): maximum 5.0 per cent, determined on at least 50 mg. Bacterial endotoxins (2.6.14): less than 300 IU/mg, if intended for use in the manufacture of parenteral preparations without a further appropriate procedure for removal of bacterial endotoxins. ASSAY Liquid chromatography (2.2.29) as described in the test for related substances with the following modifications. Reference solution. Dissolve the contents of a vial of oxytocin CRS in a 15.6 g/L solution of sodium dihydrogen phosphate R to obtain a concentration of 0.25 mg/mL. Injection: 25 μL. Calculate the content of oxytocin (C43H66N12O12S2) from the declared content of C43H66N12O12S2 in oxytocin CRS. STORAGE In an airtight container, protected from light, at a temperature of 2 °C to 8 °C. If the substance is sterile, store in a sterile, airtight, tamper-proof container. LABELLING The label states the oxytocin peptide content (C43H66N12O12S2).