title: Development and validation of a stability-indicating analytical method for the quantitation of oxytocin in pharmaceutical dosage forms.
abstract: 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.
authors.affiliation: Faculty of Pharmacy, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: F A
authors.initials: FA
authors.lastname: Chaibva
authors.forename: R B
authors.initials: RB
authors.lastname: Walker
mesh_terms: D002021:Buffers; D002138:Calibration; D002724:Chlorobutanol / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004304:Dosage Forms; D004355:Drug Stability; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D010121:Oxytocin / Q000032:analysis*; D010777:Photochemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D002021:Buffers; D004304:Dosage Forms; D007202:Indicators and Reagents; D010121:Oxytocin; D002724:Chlorobutanol