Abstract: Aim To develop and determine pinoresinol diglucopyranoside in Qing’e Pill, a traditional Chinese com-pound preparation containing Eucommia ulmoides Oliv. as the principal drug, by a reverse-phase high-performance liquid chromatographic method (RP-HPLC). Methods The extract of Qing'e Pill was refiuxed with 75% ethanol, purified on an AB-8 macroporous adsorption resin column and then injected into HPLC system. The HPLC assay was performed on an ODS analytical column with a mixture of methanol-acetonitrile-water (24:3:78, V/V/V) as the mobile phase at a flow-rate of 1.0 mL·min^-1, and a UV detector set at 227 nm. Results Good linearity between peak area and concentration was found in the range of 5.5-170 μg·mL^-1 for pinoresinol diglucopyranoside ( r>0.9998). The average recovery was 99.3%. The intra-day assay RSD and the inter-day assay RSD were 1.3% and 2.8%, respectively (n = 5). The content of pinoresinol diglucopyranoside in Qing'ePillwasdetermined to be 0.446±0.012mg·g^-1 (n = 10). Conclusion The RP-HPLC meth-od was proved to be sensitive, specific, accurate and precise for the determination of pinoresinol diglucopyranoside in Qing’e Pill.

Key words: RP-HPLC, RP-HPLC, pinoresinol diglucopyranoside, pinoresinol diglucopyranoside, Qing'e Pill, Qing'e Pill