title: Stability-indicating methods for determination of pyritinol dihydrochloride in the presence of its precursor and degradation product by derivative spectrophotometry.
abstract: A first-derivative spectrophotometric (1D) method and a derivative-ratio zero-crossing spectrophotometric (1DD) method were used to determine pyritinol dihydrochloride (I) in the presence of its precursor (II) and its degradation product (III) with 0.1N hydrochloric acid as a solvent. Linear relationships were obtained in the ranges of 6-22 microg/mL for the (1D) method and 6-20 microg/mL for the (1DD) method. By applying the proposed methods, it was possible to determine pyritinol dihydrochloride in its pure powdered form with an accuracy of 100.36 +/- 1.497% (n = 9) for the (1D) method and an accuracy of 99.92 +/- 1.172% (n = 8) for the (1DD) method. Laboratory-prepared mixtures containing different ratios of (I), (II), and (III) were analyzed, and the proposed methods were valid for concentrations of < or = 10% (II) and < or = 50% (III). The proposed methods were validated and found to be suitable as stability-indicating assay methods for pyritinol in pharmaceutical formulations.
authors.affiliation: Cairo University, Faculty of Pharmacy, Department of Analytical Chemistry, Kaser El-Aini St, ET 11562, Cairo, Egypt. mostafa1960@yahoo.com
authors.forename: Mostafa A
authors.initials: MA
authors.lastname: Shehata
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: el-Sayed
authors.forename: Mohammad G
authors.initials: MG
authors.lastname: el-Bardicy
authors.forename: Mohammad F
authors.initials: MF
authors.lastname: el-Tarras
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002712:Chlorides / Q000032:analysis* / Q000737:chemistry; D002849:Chromatography, Gas; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D013058:Mass Spectrometry; D008956:Models, Chemical; D004364:Pharmaceutical Preparations / Q000032:analysis*; D011746:Pyrithioxin / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D002712:Chlorides; D004364:Pharmaceutical Preparations; D011746:Pyrithioxin