title: [Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules].
abstract: OBJECTIVE
  To study in situ intestinal absorption kinetics of baicalin contained in Tiangou Jiangya capsules, and the effect of different intestinal segments, pH value, drug concentration and P-gp inhibitor on the absorption.
  
  
  METHODS
  The in situ intestinal perfusion test was adopted, and HPLC method was used to determine the content of baicalin in samples at different time points. Ultra-violet (UV) spectrophotometry was used to determine the content of phenol red in samples at different time points.
  
  
  RESULTS
  When pH value was at 5. 0, 6. 5, 7. 4, the absorption of baicalin was not impacted. P-gp inhibitor verapamil could enhance the absorption of baicalin. When the quality concentration of the test solution ranged between 5-20 g L -1 , the linearity of the absorption amount of baicalin increased. The absorption kinetic equation of baicalin was Y = -0. 073 7X +0. 118 7 (r = 0. 994 8) , K. 0. 073 7 h -1 , t1/2 9. 40 h.
  
  
  CONCLUSIONS
  Baicalin is mainly absorbed in colon. The absorption of baicalin shows the first-order kinetics process, with the absorption mechanism of passive diffusion. Baicalin is a substrate for P-gp.
authors.affiliation: School of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, China. lljun66@yahoo.com.cn
authors.forename: Ling-Jun
authors.initials: LJ
authors.lastname: Li
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.forename: Hua-Wei
authors.initials: HW
authors.lastname: Lou
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors; D000818:Animals; D001592:Benzyl Alcohols / Q000737:chemistry* / Q000592:standards; D005260:Female; D005419:Flavonoids / Q000737:chemistry* / Q000378:metabolism* / Q000592:standards; D005663:Furans / Q000737:chemistry* / Q000592:standards; D005960:Glucosides / Q000737:chemistry* / Q000592:standards; D006863:Hydrogen-Ion Concentration; D007408:Intestinal Absorption / Q000187:drug effects; D007700:Kinetics; D017705:Lignans / Q000737:chemistry* / Q000592:standards; D008297:Male; D011786:Quality Control; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D001592:Benzyl Alcohols; D005419:Flavonoids; D005663:Furans; D005960:Glucosides; D017705:Lignans; C560376:Tiangou; C038044:baicalin; D014700:Verapamil