title: Identification, characterization, synthesis and HPLC quantification of new process-related impurities and degradation products in retigabine.
abstract: Two new impurities were described and determined using gradient HPLC method with UV detection in retigabine (RET). Using LC-HRMS, NMR and IR analysis the impurities were identified as RET-dimer I: diethyl {4,4'-diamino-6,6'-bis[(4-fluorobenzyl)amino]biphenyl-3,3'-diyl}biscarbamate and RET-dimer II: ethyl {2-amino-5-[{2-amino-4-[(4-fluorobenzyl) amino] phenyl} (ethoxycarbonyl) amino]-4-[(4-fluorobenzyl)amino] phenyl}carbamate. Reference standards of these impurities were synthesized followed by semipreparative HPLC purification. The mechanism of the formation of these impurities is also discussed. An HPLC method was optimized in order to separate, selectively detect and quantify all process-related impurities and degradation products of RET. The presented method, which was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ) and selectivity is very quick (less than 11min including re-equilibration time) and therefore highly suitable for routine analysis of RET related substances as well as stability studies.
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic. Electronic address: michal.dousa@seznam.cz.
authors.forename: Michal
authors.initials: M
authors.lastname: Douša
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Srbek
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Rádl
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Cerný
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Klecán
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Havlíček
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Marcela
authors.initials: M
authors.lastname: Tkadlecová
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Pekárek
authors.affiliation: Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Gibala
authors.affiliation: Department of Analytical Chemistry, Charles University, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Nováková
mesh_terms: D002219:Carbamates / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004340:Drug Contamination; D004355:Drug Stability; D057230:Limit of Detection; D010655:Phenylenediamines / Q000737:chemistry*; D012015:Reference Standards
chemical_list: D002219:Carbamates; D010655:Phenylenediamines; C101866:ezogabine
keywords: HPLC; Identification; Process-related impurities; Retigabine; Synthesis