Stability-indicating methods for determination of pyritinol dihydrochloride in the presence of its precursor and degradation product by derivative spectrophotometry
Shehata, M.A.; el-Sayed, M.A.; el-Bardicy, M.G.; el-Tarras, M.F.
Journal - Association of Official Analytical Chemists 88(1): 80-86
2005
ISSN/ISBN: 0004-5756 PMID: 15759729 Document Number: 593777
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 0.1 N hydrochloric acid as a solvent. Linear relationships were obtained in the ranges of 6-22 mug/mL for the (1D) method and 6-20 mug/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 ltoreq 10% (II) and ltoreq 50% (III). The proposed methods were validated and found to be suitable as stability-indicating assay methods for pyritinol in pharmaceutical formulations.