title: Determination of the dissociation constants of ropinirole and some impurities and their quantification using capillary zone electrophoresis.
abstract: Ropinirole, 4-[2-(dipropylamino)ethyl]-1,3-dihydro-2H-indol-2-one, is a potent anti-Parkinson's disease drug developed by SmithKline Beecham Pharmaceuticals. Capillary zone electrophoresis (CZE) was used for the determination of the dissociation constants of ropinirole and five structurally related impurities, potentially formed during its synthesis and for separation and quantification of these substances. The dissociation constants obtained from the CZE measurements were confirmed by UV spectrophotometry for some of the test compounds, obtaining a good agreement between the values. Careful optimization of the running buffer composition permitted base-line resolution of the six compounds in a borate buffer containing acetonitrile and magnesium sulfate (a 100 mM borate buffer containing 30 mM MgSO4 and 20 vol.% of acetonitrile). It was shown that CZE can determine the level of these impurities, down to a level of 0.05% of the main component within 15 min.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Coufal
authors.forename: K
authors.initials: K
authors.lastname: Stulík
authors.forename: H A
authors.initials: HA
authors.lastname: Claessens
authors.forename: M J
authors.initials: MJ
authors.lastname: Hardy
authors.forename: M
authors.initials: M
authors.lastname: Webb
mesh_terms: D000978:Antiparkinson Agents / Q000737:chemistry* / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D007211:Indoles / Q000737:chemistry* / Q000302:isolation & purification; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000978:Antiparkinson Agents; D007211:Indoles; C046649:ropinirole