1. ¹Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People's Republic of China
2. ²Department of Pharmaceutics, The Second Affiliated Hospital of XiangYa Medical School, Central South University, Changsha, Hunan, People's Republic of China

Correspondence: H-H Zhou, hhzhou2003@163.com

Received 11 February 2007; Accepted 28 May 2007; Published online 12 September 2007.

Abstract

The aim of this study was to explore potential herb–drug interaction between baicalin and rosuvastatin, a typical substrate for organic anion-transporting polypeptide 1B1 (OATP1B1) related to different OATP1B1 haplotype groups. Eighteen unrelated healthy volunteers who were CYP2C9*1/*1 with different OATP1B1 haplotypes (six OATP1B1*1b/*1b, six OATP1B1*1b/*15, and six OATP1B1*15/*15) were selected to participate in this study. Rosuvastatin (20 mg orally) pharmacokinetics after coadministration of placebo and 50-mg baicalin tablets (three times daily orally for 14 days) were measured for up to 72 h by liquid chromatography–mass spectrometry in a two-phase randomized crossover study. After baicalin treatment, the area under the plasma concentration–time curve (AUC)_(0–72) and AUC_(0–) of rosuvastatin decreased by 47.011.0% (P=0.001) and 41.97.19% (P=0.001) in OATP1B1*1b/*1b, 21.020.6% (P=0.035) and 23.98.66% (P=0.004) in OATP1B1*1b/*15, and 9.2011.6% (P=0.077) and 1.764.89% (P=0.36) in OATP1B1*15/*15, respectively. Moreover, decreases of both AUC_(0–72) and AUC_(0–) of rosuvastatin among different haplotype groups were significantly different (P=0.002 and <0.001). Baicalin reduces plasma concentrations of rosuvastatin in an OATP1B1 haplotype–dependent manner.