The HPLC–MS/MS Method for Determination of Diosbulbin B in the Plasma of Rats Administered with Rhizoma Dioscoreae Bulbiferae Combinations: Application to Comparative Pharmacokinetic Study

Abstract

Diosbulbin B (DB) is a diterpenoid lactone with a remarkable anticancer effect isolated from Rhizoma Dioscoreae Bulbiferae (RDB). The present study aimed to develop a new and sensitive method for determination of DB in rats after oral administration of single herb RDB decoction and its three combinations with Radix Angelicae Sinensis (RAS). A sensitive and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) method with a multiple-reaction monitoring (MRM) mode was employed for quantification of DB in the rat plasma. DB and spinosin (internal standard, IS) were separated on an Xtimate C₁₈ column (4.6 mm × 150 mm, 5 µm) using a gradient mobile phase consisting of water and acetonitrile. The calibration curve was linear over the range of 0.5 to 500 ng/mL. The lower limit of quantification was 0.5 ng/mL. The accuracy and precision of DB in the rat plasma were between −4.2% and 8.1% relative error, and 3.2% to 9.1% relative standard deviation, respectively. The fully validated method was successfully applied to comparative pharmacokinetics (PK) of DB in RDB–RAS combinations. The results showed that components in RAS had a dramatic effect on the PK pattern of DB.

Keywords:

• diosbulbin B
• LC–MS/MS
• pharmacokinetics
• RDB
• RAS
• rat plasma