Laboratory of Clinical Pharmaceutics and Therapeutics

Sapporo, Japan

Laboratory of Clinical Pharmaceutics and Therapeutics

Sapporo, Japan
SEARCH FILTERS
Time filter
Source Type

Itagaki S.,Laboratory of Clinical Pharmaceutics and Therapeutics | Ochiai A.,Laboratory of Clinical Pharmaceutics and Therapeutics | Kobayashi M.,Laboratory of Clinical Pharmaceutics and Therapeutics | Sugawara M.,Laboratory of Pharmacokinetics | And 2 more authors.
Food Chemistry | Year: 2010

Coenzyme Q10 (CoQ10) is very widely consumed by humans as a food supplement. However, CoQ10 is taken up from the intestine into the circulation at a low rate. The absorption of compounds from the gastrointestinal tract is one of the important determinants for oral bioavailability. Secretory transport limits the oral bioavailability of compounds. It has been reported that efflux transport of CoQ10 is mediated by P-glycoprotein (P-gp) in Caco-2 cells. We tried to improve intestinal absorption of CoQ10 by modulating P-gp. Since grapefruit juice (GFJ) is reported to inhibit P-gp function, we investigated the effect of GFJ on the transport of CoQ10 by Caco-2 cells. In the presence of GFJ, the basal-to-apical transport of CoQ10 was decreased and the uptake of CoQ10 was increased. These findings suggest that the combined administration of CoQ10 and GFJ could enhance CoQ10 absorption. © 2009 Elsevier Ltd. All rights reserved.


Yamaguchi H.,Hokkaido University | Miyamori K.,Hokkaido University | Sato T.,Hokkaido University | Ogura J.,Hokkaido University | And 5 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2014

A liquid chromatography/tandem mass spectrometry method for the determination of intracellular accumulation in addition to transcellular transport of digoxin and ouabain in renal epithelial HK-2 cells was developed. The solid-phase extraction Bond Elut® C18 (100mg/1mL) cartridge was used for the extraction of digoxin and ouabain from extracellular (medium) and intracellular (cell lysate) matrices. Chromatographic separation was performed on a CAPCELL PAK C18 MGII column (2.0mm×150mm, 5μm). This method covered a linear range of 0.5-1000ng/mL of concentrations in medium and 0.5-1000ng of concentrations in cell lysate for digoxin and ouabain. The intra-day precision and inter-day precision of analysis were less than 11.9%, and the accuracy was within ±11.6%. The total run time was 16min. Our method was successfully applied to the transport experiments of digoxin and ouabain by HK-2 cell monolayers. © 2014 Elsevier B.V.


Itagaki S.,Laboratory of Clinical Pharmaceutics and Therapeutics | Oikawa S.,Laboratory of Clinical Pharmaceutics and Therapeutics | Ogura J.,Laboratory of Clinical Pharmaceutics and Therapeutics | Kobayashi M.,Laboratory of Clinical Pharmaceutics and Therapeutics | And 2 more authors.
Food Chemistry | Year: 2010

Quercetin-3-rhamnoglucoside (rutin) has a wide spectrum of biochemical and pharmacological activities. Orally administered compounds are absorbed in the intestine. Although absorption of rutin from the jejunum of the rat was good, binding of rutin to the intestinal wall components may limit its absorption from the small intestine. The physiological importance of an orally administered compound depends on its interaction with target tissues. Since there is limited information on the importance of rutin in vivo, we focused on the protective effect of rutin on intestinal injury. The intestinal mucosa is extremely sensitive to reactive oxygen species. We used a rat mesenteric ischemia-reperfusion (I/R) injury model as a model of oxidative injury and investigated the antioxidant activities of rutin in vivo. We found that rutin, which has combined antioxidant activity from radical-scavenging, xanthine oxidase inhibition and chain-breaking effects, exhibits a protective effect on I/R injury in the rat small intestine. © 2009 Elsevier Ltd.

Loading Laboratory of Clinical Pharmaceutics and Therapeutics collaborators
Loading Laboratory of Clinical Pharmaceutics and Therapeutics collaborators