RESUMO
Five unknown impurities ranging from 0.05 to 0.2% in donepezil were detected by a simple isocratic reversed-phase high performance liquid chromatography (HPLC). These impurities were isolated from crude sample of donepezil using isocratic reversed-phase preparative high performance liquid chromatography. Based on the spectral data (IR, NMR and MS), the structures of these impurities were characterised as 5,6-dimethoxy-2-(4-pyridylmethyl)-1-indanone (impurity I), 4-(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity II), 2-(1-benzyl-4-piperdylmethyl)-5,6-dimethoxy-1-indanol (impurity III) 1-benzyl-4(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity IV) and 1,1-dibenzyl-4(5,6-dimethoxy-1-oxo-2,3-dihydro-2H-2-indenylmethyl)hexahydropyridinium bromide (impurity V). The synthesis of these impurities and their formation was discussed.
Assuntos
Indanos/química , Piperidinas/química , Inibidores da Colinesterase/química , Cromatografia Líquida de Alta Pressão/métodos , Donepezila , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
An isocratic chiral HPLC method was developed for the separation of tolterodine tartarate enantiomers. The mobile phase consists of n-hexane and isopropyl alcohol in the ratio of 980:20 (v/v) with 1 ml diethylamine and 0.6 ml trifluoroacetic acid. Chiralcel OD-H (250 mm x 4.6mm) column was used at constant room temperature. Flow rate was kept at 0.5 ml/min. This method is capable of detecting the S-isomer up to 0.1 microg/ml. The method was validated in terms of linearity, precision, limit of detection (LOD) and limit of quantification (LOQ).
Assuntos
Compostos Benzidrílicos/química , Cresóis/química , Fenilpropanolamina/química , Cromatografia Líquida de Alta Pressão , Estrutura Molecular , Reprodutibilidade dos Testes , Estereoisomerismo , Tartarato de TolterodinaRESUMO
In the synthesis of Moxifloxacin four prominent impurities were detected in HPLC analysis. These impurities were detected in gradient HPLC method. They were isolated from enriched mother liquors and were characterized as 1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-[(S,S)-N-methyl-2,8-diazabicyclo (4,3,0) non-8yl]-4-oxo-3-quinoline carboxylic acid (Impurity-1), methyl-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-[(S,S)-2,8-diazabicyclo(4,3,0)non-8-yl]-4-oxo-3-quinoline carboxylate (impurity-2), and 1-cyclopropyl-6-fluoro-1,4 dihydro-8-hydroxy-7-[(S,S)-2,8-diazobicyclo(4,3,0)non-8-yl]-4-oxo-3-quinoline carboxylicacid (impurity-3), 1-cyclopropyl-6,7-difluoro-8-hydroxy-4-oxo-1,4 dihydro-3-quinoline carboxylicacid (impurity-4) by means of 1H, 13C NMR, DEPT, IR and mass spectral data. Structural elucidation by spectral data was discussed.
Assuntos
Compostos Aza/análise , Compostos Aza/química , Contaminação de Medicamentos , Quinolinas/análise , Quinolinas/química , Cromatografia Líquida de Alta Pressão , Fluoroquinolonas , Espectroscopia de Ressonância Magnética , Espectrometria de Massas/métodos , Estrutura Molecular , Moxifloxacina , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Three unknown impurities and a byproduct in repaglinide bulk drug at levels below 0.1% (ranging from 0.05 to 0.1%) were detected by a simple isocratic reversed-phase high performance liquid chromatography (HPLC) method. These impurities were isolated from crude sample of repaglinide using reversed-phase preparative high performance liquid chromatography. Based on the spectroscopic data (IR, NMR and MS) the structures of these impurities (I, II and IV) and byproduct (III) were characterised as 4-carboxymethyl-2-ethoxy-benzoic acid (I), 4-cyclohexylaminocarbamoylmethyl-2-ethoxy-benzoic acid (II), 1-cyclohexyl-3-[3-methyl-1-(2-piperidin-1-yl-phenyl)-butyl]-urea (IV) and 1,3-dicyclohexyl urea (III), respectively. Their synthesis and formation is discussed.
