title: The influence of bile salts and mixed micelles on the pharmacokinetics of quinine in rabbits.
abstract: The bioavailability of orally administered drugs can be influenced by interactions with food components and by physico-chemical conditions in the upper gastrointestinal tract. Normally, bile salts enhance the transport of lipophilic drugs across mucosal membranes. Bile salts are able to form stable mixed micelles consisting of fatty acids and phospholipids. Conventional micellar systems are known to solubilize lipophilic drugs having a low bioavailability. The influence of bile salts and mixed micelles on the pharmacokinetics of the lipophilic drug quinine was investigated in rabbits. Female rabbits were given intraduadenally quinine (5 mg/kg body weight) without and with incorporation into the micellar or mixed micellar systems. Blood was collected every 30 min for 6 h. In plasma, concentration of quinine was measured using HPLC. The plasma concentration-time profiles of quinine were significantly lower within the first 2 h after administration in presence of both the sodium salt of glycodeoxycholic acid (above the critical micellar concentration) as well as of mixed micellar systems consisting of glycodeoxycholic acid and palmitic acid and/or lecithin. The pharmacokinetic parameters AUC (relative bioavailability) and c(max) of quinine were significantly decreased by micellar systems in rabbits. These mixed micellar systems lower and not as expected, increase the absorption of quinine in vivo. Therefore, quinine should be orally administered at least 1h before food intake, particularly before fat intake.
authors.affiliation: Research Group Food Chemistry and Preventive Nutrition, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Dongowski
authors.forename: Bertram
authors.initials: B
authors.lastname: Fritzsch
authors.forename: Jochen
authors.initials: J
authors.lastname: Giessler
authors.forename: Albert
authors.initials: A
authors.lastname: Härtl
authors.forename: Olaf
authors.initials: O
authors.lastname: Kuhlmann
authors.forename: Reinhard H H
authors.initials: RH
authors.lastname: Neubert
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001647:Bile Acids and Salts / Q000494:pharmacology*; D001682:Biological Availability; D004386:Duodenum; D005227:Fatty Acids / Q000737:chemistry; D005260:Female; D006002:Glycodeoxycholic Acid / Q000494:pharmacology; D007441:Intubation, Gastrointestinal; D008823:Micelles; D019308:Palmitic Acid / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000494:pharmacology; D010743:Phospholipids / Q000737:chemistry; D011803:Quinine / Q000737:chemistry / Q000493:pharmacokinetics*; D011817:Rabbits
chemical_list: D000962:Antimalarials; D001647:Bile Acids and Salts; D005227:Fatty Acids; D008823:Micelles; D010713:Phosphatidylcholines; D010743:Phospholipids; D019308:Palmitic Acid; D006002:Glycodeoxycholic Acid; D011803:Quinine