Abstract��
OBJECTIVE To prepare the 7th bacterial endotoxin national standard material. METHODS Escherichia coli O11B4 was cultured and harvested by routine method�� bacterial liquid was broken by supersound�� then crude endotoxin material was extracted by hot phenol-water. After sufficient dialysis to remove all traces of phenol�� endotoxin was concentrated. The supernatant was chosen and purified by ultracentrifge at 105 000��g at 4 �� for 4 h. Finally the sediment was freeze-dried. Three batches of endotoxin material candidate were prepared by this method�� and one of the batches was ascertained to be bacterial endotoxin national standard material by physical chemical and biological activity assay. A series of comparison were carried out between bacterial endotoxin international standard�� national standard (the 6th batch) and Japanese national standard. RESULTS No.3 endotoxin material showed the best biological activity and lowest impurity content. CONCLUSION Three batches of endotoxin material almost have the same biological activity, physical and chemical character. The extract method has good stability and reproducibility. Compared by biological activity and impurity content�� the No.3 endotoxin material can be used for preparing new batch of bacterical endotoxin national standard material.
2010, Vol. 45 