QUALITY CONTROL OF SAN’AO TABLETS VIA X-RAY DIFFRACTION AND ELEC TRON SPIN RESONANCE TECHNIQUES

Yezhuo Zhao, Dayong Lu

ABSTRACT:Both X-ray diffraction (XRD) and electron spin resonance (ESR) techniques were used to investigate San’ao tablets and their ingredients. Three XRD peaks at 2θ = 16.10°, 22.52° and 34.46°, which arise mainly from a kind of pharmaceutic excipient—microcrystalline cellulose, are characteristic of San’ao tablets. Calcium oxalate monohydrate and calcium oxalate without crystalliferous water, as two different forms of crystalline metabolites, are identified to exist in ephedra and licorice, respectively. The ESR spectra of San’ao tablets mainly consist of those of four kinds of Chinese herbal ingredients—ephedra, bitter almonds, licorice, and ginger, independent of pharmaceutic excipients. The Mn2+ signal in San’ao tablets mainly arise from ephedra and licorice. The combination of XRD and ESR can provide a new method for quality control of San’ao tablets.

Keywords:San’ao tablets, X-ray diffraction, electron spin resonance, quality control.