RESUMO
Rivastigmine is a drug against Alzheimer's disease, and is a non-pharmacopoeial compound. During the preparation of rivastigmine in our laboratory, two impurities were detected and identified with a simple and sensitive reversed-phase liquid chromatography coupled with electrospray-mass spectrometry. The same impurities were also observed in commercial batches. These impurities were isolated by preparative HPLC and co-injected with rivastigmine sample to confirm the retention times in HPLC. These impurities were characterized as N,N-dimethyl-3-[1-dimethylaminoethyl]phenylcarboxylate (dimethyl-rivastigmine) and N,N-diethyl-3-[1-dimethylaminoethyl]phenylcarboxamide (diethyl-rivastigmine). Structural elucidation of these impurities by spectral data (1H NMR, 13C NMR and MS) is discussed.
Assuntos
Inibidores da Colinesterase/análise , Contaminação de Medicamentos , Fenilcarbamatos/análise , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Rivastigmina , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Didanosine is an antiviral drug. During the preparation of didanosine in our lab, six process related known impurities and one unknown impurity were detected in HPLC analysis at levels ranging from 0.05 to 0.8%. The same unknown impurity was also observed in commercial batches. This new impurity was isolated by preparative HPLC and co-injected with didanosine sample to confirm the retention times in HPLC. This impurity was characterized as, 9-(2,3,5-trideoxy-beta-D-glycero-pentofuranosyl)-9H-purin-6-one (2',3',5'-trideoxyinosine). Structural elucidation of this impurity by spectral data (1H NMR, 13C NMR, MS and IR) has been discussed.
