Raman study of impurity influence on active center in artemisinin

Abstract

The unusual endoperoxide bridge is believed to be the active center for artemisinin activations. Our Raman study indicated that the active center endoperoxide bridge is more significantly influenced by impurity than other parts in artemisinin molecule. This phenomenon provides a Raman spectroscopy method for quantitative measurement of impurity content basing on the relative intensity ratio analysis of characteristic vibrational modes. The proposed Raman method can be a good alternative to high performance liquid chromatography, which is a commonly applied technique for measuring impurity content. Also, the Raman method can provide additional information of impurity homogeneity. In addition, Raman imaging is presented for easy visualization of impurity content and homogeneity in artemisinin simultaneously.

Keywords: Artemisinin; Homogeneity; Impurity content; Raman imaging; Raman spectroscopy; Relative intensity ratio.