The present invention provides dimethyl sulphoxide solvate of 4-(4-{3-[4-chloro- 3-(trifluoromethyl)phenyl]ureido }phenoxy)-N -methylpyridine-2-carboxamide, process for its preparation, pharmaceutical composition comprising it and its use for the treatment of cancer. The present invention also provides a novel HPLC method for the identification, quantification and isolation of related substances of sorafenib.