Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The retention behaviour and selectivity of selected basic, neutral and acidic peptides have been studied by capillary electroendoosmotic chromatography (CEC) with Hypersil C8, C18, Hypersil mixed-mode, and Spherisorb C18/SCX columns, 250 (335) mm x 100 microns, packed with 3 microns particles, and eluted with mobile phases composed of acetonitrile-triethylamine-phosphoric acid (TEAP) at pH 3.0 using a Hewlett-Packard Model HP3DCE capillary electrophoresis system. The selected peptides were desmopressin (D), two analogues (A and B) of desmopressin, oxytocin (O) and carbetocin (C). The peptides eluted either before or after the electroendoosmotic flow (EOF) marker, depending on the concentration of acetonitrile used and the buffer ionic strength. The retention and selectivity of these peptides under CEC conditions were compared to their behaviour in free zone capillary electrophoresis (CZE), where the separation mode was based on the electrophoretic migration of the analytes due to their charge and Stokes radius properties. In addition, their retention behaviour in RP-HPLC was also examined. As a result, it can be concluded that the elution process of this group of synthetic peptides in CEC with a TEAP buffer at pH 3.0 is mediated by a combination of both electrophoretic migration processes and retention mechanisms involving hydrophobic as well as silanophilic interactions. This CEC method when operated with these 3 microns reversed-phase and mixed-mode sorbents with peptides is thus a hybrid of two well-known analytical methods, namely CZE and RP-HPLC. However, the retention behaviour and selectivity of the selected peptides differs significantly in the CEC mode compared to the RP-HPLC or CZE modes. Therefore this CEC method with these peptides represents an orthogonal analytical separation procedure that is complimentary to both of these alternative techniques.
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PMID:Separation of selected peptides by capillary electroendoosmotic chromatography using 3 microns reversed-phase bonded silica and mixed-mode phases. 1048 34

The successful coupling of capillary electrochromatography (CEC) to an ion trap mass spectrometer via a nanoelectrospray interface (nESI) is described. Using a conductively coated tip butted to the end of a CEC column, it was possible to obtain a stable spray without any sheath liquid being employed. Selected small peptides were separated with CEC columns (100 microm i.d./25 cm long) packed with 3 microm Hypersil C8 or C18 bonded silica particles with an eluent composed of ammonium acetate/acetonitrile. Peptide mixtures of desmopressin, peptide A, oxytocin, carbetocin and [Met(5)]-enkephalin were detected in the mid-attomole range, which is the lowest amount analyzed using CEC combined with MS detection. It was also observed that sensitivity can be compromised at higher separation voltages. We demonstrate that CEC/nESI-MS, at the current stage of development, represents one of the most sensitive systems for peptide analysis.
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PMID:Capillary electrochromatography/nanoelectrospray mass spectrometry for attomole characterization of peptides. 1093 36

The action of certain substances on the release of oxytocin has been studied in unanaesthetized lactating rats. The release of oxytocin has been assessed by the increase in weight after suckling of rats separated overnight from the mother. A large variety of substances appear to block the release of oxytocin. These include pentolinium, atropine and chlorpromazine. Adrenaline and noradrenaline also cause a block in the release of oxytocin, and it is suggested that adrenaline blocks the central release of oxytocin as well as blocking its peripheral action. Reserpine and oestradiol in the doses administered did not block the release of oxytocin. Block also occurred after the ingestion of water, ethanol and normal saline, an effect which may be produced indirectly by impulses from the gastro-intestinal tract.
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PMID:Release of oxytocin in unanaesthetized lactating rats. 1387 86

A single stability-indicating assay for oxytocin (OT) in pharmaceutical dosage forms using gradient elution over 21 min has been reported in the literature. Furthermore, published and compendial methods for the analysis of OT containing dosage forms also involve using HPLC with gradient elution and complicated mobile phases that include hydrophobic ion pairing agents. A simple isocratic and stability-indicating assay was developed and validated. The conditions are as follows, column: Phenomenex C18 Hypersil, 5 microm packing, 4.6 mm x 150 mm with acetonitrile-phosphate buffer (pH 5; 0.08 M) (20:80) as the mobile phase with UV detection at 220 nm The method was found to be specific for OT in the presence of degradation products and chlorbutol (preservative) with an overall analytical run time of 16 min. Accuracy was determined to be 0.77-1.18% bias for all samples tested. Intra-assay precision (repeatability) was found to be 0.22-1.04%R.S.D. while the inter-day precision (intermediate precision) was found to be 1.27-1.68%R.S.D. for the samples studied. The calibration curve was found to be linear with the equation y = 1.81x + 0.02 and a linear regression coefficient of 0.9991 over the range 0.4-12.0 IU/ml. The LOD and the LOQ were determined to be 0.1 and 0.4 IU/ml, respectively. Syntocinon, a commercially available dosage form of OT was assayed resulting in 100.5-106.6% recovery of the label claim and an average of 10.04 IU/ml.
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PMID:Development and validation of a stability-indicating analytical method for the quantitation of oxytocin in pharmaceutical dosage forms. 1692 Mar 23

Novel mucoadhesive buccal tablets (NMBTs) of oxytocin were prepared as cores in cup fashion to release and permeate the drug unidirectionally toward the buccal mucosa to reach the systemic circulation directly. Adhesive cups for NMBTs were prepared with mucilage (DPM) isolated from edible Diospyros peregrina fruit. Mucoadhesive properties like shear and tensile and peel strengths of the adhesive cups were estimated on freshly excised bovine buccal mucosa. Core tablets were formulated with oxytocin using two penetration enhancers, sodium taurocholate and sodium thioglycollate. In vitro permeability studies of NMBTs were conducted in a Franz diffusion cell containing 50 ml of phosphate buffer, pH 6.6, at 37+/-0.2 degrees C through excised bovine buccal mucosa, and the amount of drug permeated was estimated at 220 nm on reverse-phase HPLC using a BDS Hypersil C(8) column with acetonitrile and potassium dihydrogen orthophosphate buffer 0.05 M, pH 6.6, (20 : 80 v/v) as the mobile phase, at flow rate of 1.25 ml/m. The NMBTs containing 0.75% w/w sodium taurocholate showed 26% permeability without damaging the histology of the buccal mucosa. The results suggest that this formulation may be a suitable alternative to oxytocin injections.
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PMID:In vitro evaluation of novel mucoadhesive buccal tablet of oxytocin prepared with Diospyros peregrina fruit mucilages. 1837 77

Novel mucoadhesive buccal tablets (NMBT) of oxytocin were prepared as core in cup fashion to release the drug unidirectionally towards the buccal mucosa. Adhesive cups were prepared with a mucilage isolated from edible Dillenia indica fruits (DIM). Shear, tensile and peel strengths of prepared adhesive cups were estimated on freshly excised bovine buccal mucosa. Core tablets were formulated with oxytocin using permeation enhancers viz. sodium taurocholate and sodium thioglycollate. In vitro permeability studies of NMBT were conducted in a Franz diffusion cell containing 50 mL of phosphate buffer pH 6.6 at 37 +/- 0.2 degrees C through excised bovine buccal mucosa. In vivo studies on anaesthetized New Zealand albino male rabbits were conducted and drug levels in plasma were estimated at 220 nm by reverse phase HPLC using BDS Hypersil C8 column using acetonitrile and 0.05 M potassium dihydrogen orthophosphate buffer pH 6.6 (20:80 v/v) as mobile phase, at a flow rate of 1.25 mL/ min. Optimized formulation showed C(max), T(max), t1/2 and AUC(total), 688 pg/mL, 2 h, 0.079 h, and 1999.72 h x pg/mL respectively. The NMBT containing 0.75% w/w sodium taurocholate showed 27% bioavailability without damaging the buccal mucosasuggesting its suitability as an alternative to noninvasive administration of oxytocin.
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PMID:In vitro and in vivo evaluation of a novel mucoadhesive buccal oxytocin tablet prepared with Dillenia indica fruit mucilage. 1846 85