Determination of baicalin and puerarin in traditional Chinese medicinal preparations by high-performance liquid chromatography

HPLC methods for the determination of baicalin in Scutellariae Radix and puerarin in Puerariae Radix were established for the quality control of Chinese medicinal preparations containing these drugs. Ethyl para ben and methyl para ben were used as the internal standards for baicalin and puerarin respectively. The samples were separated on a Cosmosil 5C18 column with 0.03% phosphoric acid-acetonitrile (79:21). 0.03% phosphoric acid-acetonitrile (87: 13) and 2% acetic acid-methanol (79:21) as mobile phases at flowrates of 1.0 ml/min. Very satisfactory and reproducible results were obtained within 25 min for baicalin and 50 min for puerarin. These methods were also applicable to other prescriptions containing Scutellariae Radix and Puerariae Radix such as Chair-Ger-Jie-Ji-Tang, Dang,Guei-Nian-Tong-Tang and San-Jong-Kuey-Jian-Tang.