Table of Contents
Chromatography Research International
Volume 2011, Article ID 929876, 9 pages
Research Article

Stability-Indicating Gradient RP-LC Method for the Determination of Process and Degradation Impurities in Bosentan Monohydrate: An Endothelin Receptor Antagonist

1Research and Development, Megafine Pharma (P) Ltd., Nashik 422 202, India
2Department of Chemistry, Deogiri College, Aurangabad 431004, India

Received 16 June 2011; Revised 29 July 2011; Accepted 2 August 2011

Academic Editor: Cristina Minguillรณn

Copyright ยฉ 2011 Sanjay A. Jadhav et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Described is a simple, rapid, selective, and stability-indicating RP-LC method for the determination of process and degradation-related impurities of bosentan monohydrate. Chromatographic separation was achieved on Zorbax SB-Phenyl column thermostated at 3 5 โˆ˜ C under gradient elution by a binary mixture of solvent A (60% phosphate buffer, pH 2.5, and 40% methanol) and solvent B (acetonitrile) at a flow rate of 1.0 mL/min. Forced degradation was carried out under acidic, alkaline, oxidative, photolytic, and thermal conditions. Significant degradation is observed in acid and alkali stress conditions. Process- and degradation-related impurities were characterized by mass spectrometry, 1H NMR, and FT-IR spectral data. Validation of the developed method was carried out as per ICH requirements. Regression analysis shows an “ ๐‘Ÿ ” value (correlation coefficient) of greater than 0.999 for bosentan and five potential impurities. This method was capable to detect the five impurities at 0.01% of the test concentration of 1.0 mg mL−1.