Simultaneous determination of tamoxifen citrate and its E isomer impurity in bulk drug and tablets by high-performance liquid chromatography.
A new stability-indicating HPLC method that is highly selective for the separation of E and Z isomers of tamoxifen citrate [(Z)-2-[p-(1,2-diphenyl-1-butenyl)phenoxy]-N,N-dimethylethylamine citrate] is described. The method can be used to assay tamoxifen citrate and the E isomer impurity in both bulk drug and tablets. The chromatographic system consists of a 5-microns octadecyl silica column and a mobile phase composed of an aqueous phosphate buffer (pH 2.0) and acetonitrile. N,N-Dimethyloctylamine is used as an additive in the mobile phase for improving the peak shape of tamoxifen citrate. Compared with the existing official U.S. and British Pharmacopeia methods, the new method offers the following advantages: better resolution between the E and Z isomers, shorter analyses time, stability indication, and a less aggressive mobile phase that results in a longer column life.
Jalonen
H G
HG
Farmos Group, Ltd., Pharmaceutical Division, Research Center, Turku, Finland.
D002851:Chromatography, High Pressure Liquid; D007202:Indicators and Reagents; D007536:Isomerism; D013607:Tablets; D013629:Tamoxifen / Q000032:analysis*
D007202:Indicators and Reagents; D013607:Tablets; D013629:Tamoxifen