Isolation and characterization of some potential impurities in ropinirole hydrochloride

Three impurities in ropinirole hydrochloride drug substance at levels similar to 0.06-0.15% were detected by reverse-phase high performance liquid chromatography (HPLC). These impurities were isolated from the drug substance. These impurities were analyzed using reverse-phase HPLC. Based on the spectral data (M NMR and MS), structures of these impurities were characterized as 4-[2-(propylamino) ethyl]- 1,3-dihydro-W-indol-2-one hydrochloride (impurity-A), 5-[2-(diropylamino) ethyl] - 1,4-dihydro-3H-benzoxazin-3-one hydrochloride (impurity-B) and 4-[2-(diropyl amino) ethyl]-1H-indol-2.3-dione hydrochloride (impurity-C). Synthesis of these impurities is discussed. (c) 2006 Elsevier B.V. All rights reserved.