To study the effect of the particle size on the active (toxic) component contents of Semen Strychni powder, 20—200 mesh of Semen Strychni powder samples were prepared. The micro morphology of these samples were characterized by scanning electron microscope (SEM) and the samples were qualitatively identified by TLC. The contents of brucine and strychnine of each sample were determined by HPLC. The results indicated that there
existed some differences between morphology compositions of Semen Strychni powder samples with different particle sizes. Moreover, the contents of brucine, strychnine of different samples were different, and
the contents of brucine (or strychnine) in some samples of Semen Strychni powder
were significantly different
. So when Semen Strychni powder is applied to traditional Chinese medicine, its particle size should be highly controlled. Upon the results of the research, the particle size of Semen Strychni powder had better be 100—200 mesh.