title: A new system for the prediction of drug absorption using a pH-controlled Caco-2 model: evaluation of pH-dependent soluble drug absorption and pH-related changes in absorption.
abstract: One purpose of this study was to develop a new system for the prediction of pH-dependent soluble drug absorption that takes into account the physiological condition of the gastrointestinal tract. Another purpose was to establish several models of different gastric acidities: a normal gastric acidity model, a low gastric acidity model (a model of achlorhydria), a temporarily elevated gastric acidity model (a model of a case in which an acidic drug was coadministered to temporarily elevate gastric acidity in the case of low gastric acidity), a weak antacid model (a model of a case in which a weak antacid drug, such as an H(2) receptor antagonist, was coadministered to temporarily elevate pH up to 6), and a strong antacid model (a model of a case in which a strong antacid drug, such as magnesium hydroxide, was coadministered to temporarily elevate pH up to 8.0). These models were used to evaluate variation in pH-related absorption in humans. Dipyridamole preparation (Persantin tablets) and glibenclamide preparation (Euglucon tablets), both poorly water-soluble and pH-dependent soluble drugs, were chosen as model drugs to determine whether absorption is altered by changes in levels of gastric acid. The extent of absorption of dipyridamole was remarkably lower when gastric pH was continuously elevated to 6.0, whereas it was increased when gastric pH temporarily decreased to 1.8. The extent of absorption of glibenclamide increased dramatically when gastric pH temporarily increased to 8.0, but did not change when gastric pH temporarily increased to 6.0. These results are consistent with reported results obtained in clinical studies. The results suggest that pH-related variations in absorption in humans can be accurately predicted using our new system.
authors.affiliation: Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Kita 14 jo, Nishi 5 chome, Kita-ku, Sapporo 060-8648, Japan.
authors.forename: Xin
authors.initials: X
authors.lastname: He
authors.forename: Shota
authors.initials: S
authors.lastname: Kadomura
authors.forename: Yoh
authors.initials: Y
authors.lastname: Takekuma
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sugawara
authors.forename: Katsumi
authors.initials: K
authors.lastname: Miyazaki
mesh_terms: D018938:Caco-2 Cells; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007408:Intestinal Absorption / Q000502:physiology*; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011237:Predictive Value of Tests; D012995:Solubility
chemical_list: D004364:Pharmaceutical Preparations