[Effect of Huangqi decoction on entecavir pharmacokinetics in rat plasma]

Entecavir (ETV), a guanosine nucleotide antiviral agent with activity against hepatitis B virus (HBV) and Huangqi decoction (HQD) that exerts significant therapeutic effects in liver cirrhosis are used as an effective drug combination in the treatment of liver cirrhosis with HBV. Therefore, this study was designed to assess the effect of HQD on ETV pharmacokinetics in rat plasma. Spraque-Dawley (SD) rats were randomized into single- and 7-day-dose experimental groups. The ETV and ETV-HQD groups were administered ETV and a simultaneous combination of ETV and HQD, respectively while the ETV-HQD-2h group received HQD 2 h after ETV treatment, all administered via intragastric (i.g.) gavage. A rapid, sensitive, and efficient ultra-high- performance liquid chromatography-linear trap quadrupole (UHPLC-LTQ)-Orbitrap method was developed and validated to determine ETV in rat plasma from blood samples collected at different time points following treatment. The linearity, accuracy, precision, recovery, matrix effects and stability of ETV were all satisfactory. The ETV-HQD group exhibited a decrease in the maximum plasma concentration (Cmax), and a delay in time to achieve Cmax (tmax) following single- and multi-dose administrations, and decreased area under the concentration- time curve (AUC0–t) following single dosing. ETV pharmacokinetics did not change significantly between the ETV and ETV-HQD-2h groups. In vitro everted intestinal sac models experiments indicated that HQD decreased the absorption of ETV. HQD prevented ETV from accessing the intestinal mucosa epithelial surface, thereby decreasing its absorption in rats.