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Determination, purity assessment and chiral separation of levodopa methyl ester in bulk and formulation pharmaceuticals
Author(s) -
Wang Jie,
Fang Yuzhi
Publication year - 2006
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.617
Subject(s) - chemistry , chromatography , enantiomer , phosphoric acid , high performance liquid chromatography , acetonitrile , elution , potassium , resolution (logic) , methanol , sodium , pharmaceutical formulation , detection limit , stereochemistry , organic chemistry , artificial intelligence , computer science
A sensitive, reliable and reproducible HPLC method with electrochemical detection (HPLC‐ECD) has been developed for the separation and quantification of levodopa methyl ester (LDME) and its impurities such as levodopa ( l‐ DOPA), 3‐methoxytyrosine (MTS) and l ‐tyrosine (TS) in bulk drug and pharmaceutical dosage form. The separation was performed on an LC 18 column by isocratic elution with methanol–acetonitrile–50 m m potassium dihydrogen phosphate (8:2:90, v/v/v) containing 5 m m sodium 1‐hexanesulfonate, 5 m m EDTA and 5 m m sodium chloride, adjusted with phosphoric acid to a pH of 3.2 as mobile phase. The correlation coefficients of linear regression for LDME, l‐ DOPA, MTS and TS were more than 0.999. The detection limits for l ‐DOPA, MTS and TS were 3.15, 2.04 and 2.88 ng/mL, respectively. The precision was checked in terms of F ‐test variance ratio using potentiometric titration as reference. The separation of dopa methyl ester enantiomers by chiral chromatography is also described. This method is capable of separating the two enantiomers with a selection of 1.4 and a resolution of 8.4. Both methods were found to be stable and useful in the quality control of the bulk material and formulations. Copyright © 2006 John Wiley & Sons, Ltd.