title: An in vivo microdialysis measurement of harpagoside in rat blood and bile for predicting hepatobiliary excretion and its interaction with cyclosporin A and verapamil.
abstract: Harpagoside, a major bioactive iridoid glucoside in genus Scrophularia, has been widely used in clinical practice for the treatment of pain in the joints and lower back for its neuroprotective and anti-inflammation activities. To investigate the pharmacokinetics and hepatobiliary excretion, an in vivo microdialysis method coupled with high performance liquid chromatography was developed to monitor the concentration of harpagoside in blood and bile. The harpagoside bile-to-blood distribution ratio (AUC(bile)/AUC(blood)) up to 986.28+/-78.46 significantly decreased to 6.41+/-0.56 or 221.20+/-18.92 after co-administration of cyclosporin A or verapamil. The results indicated that harpagoside went through concentrative elimination from the bile which was probably regulated by P-glucoprotein, providing possible clinical trials of co-administration of transporter inhibitors to decrease drug efflux, thus to enhance the curative effects.
authors.affiliation: Key Laboratory of Modern Chinese Medicines, China Pharmaceutical University, Ministry of Education, No. 24 Tongjia Lane, Nanjing 210009, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Wen
authors.forename: Lian-Wen
authors.initials: LW
authors.lastname: Qi
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Yi
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Bi
authors.forename: Ping
authors.initials: P
authors.lastname: Li
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry* / Q000378:metabolism; D016572:Cyclosporine / Q000493:pharmacokinetics*; D004347:Drug Interactions; D006027:Glycosides / Q000032:analysis* / Q000097:blood / Q000493:pharmacokinetics*; D017551:Microdialysis / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics; D011714:Pyrans / Q000032:analysis* / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D032266:Scrophularia / Q000737:chemistry; D014700:Verapamil / Q000493:pharmacokinetics*
chemical_list: D006027:Glycosides; D010936:Plant Extracts; D011714:Pyrans; D016572:Cyclosporine; C033249:harpagoside; D014700:Verapamil