1999年2月
Effects of intestinal CYP3A4 and P-glycoprotein on oral drug absorption - Theoretical approach
PHARMACEUTICAL RESEARCH
- ,
- ,
- 巻
- 16
- 号
- 2
- 開始ページ
- 225
- 終了ページ
- 231
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1023/A:1018872207437
- 出版者・発行元
- KLUWER ACADEMIC/PLENUM PUBL
Purpose. To evaluate the effects of gut metabolism and efflux on drug absorption by simulation studies using a pharmacokinetic model involving diffusion in epithelial cells.
Methods. A pharmacokinetic model for drug absorption was constructed including metabolism by CYP3A4 inside the epithelial cells, P-gp-mediated efflux into the lumen, intracellular diffusion from the luminal side to the basal side, and subsequent permeation through the basal membrane. Partial differential equations were solved to yield an equation for the fraction absorbed from gut to the blood. Effects of inhibition of CYP3A4 and/or P-gp on the fraction absorbed were simulated for a hypothetical substrate for both CYP3A4 and P-gp.
Results. The fraction absorbed after oral administration was shown to increase following inhibition of P-gp. This increase was more marked when the efflux clearance of the drug was greater than the sum of the metabolic and absorption clearances and when the intracellular diffusion constant was small. Furthermore, it was demonstrated that the fraction absorbed was synergistically elevated by simultaneous inhibition of both CYP3A4 and P-gp.
Conclusions. The analysis using our present diffusion model is expected to allow the prediction of in vivo intestinal drug absorption and related drug interactions from in vitro studies using human intestinal microsomes, gut epithelial cells, CYP3A4-expressed Caco-2 cells, etc.
Methods. A pharmacokinetic model for drug absorption was constructed including metabolism by CYP3A4 inside the epithelial cells, P-gp-mediated efflux into the lumen, intracellular diffusion from the luminal side to the basal side, and subsequent permeation through the basal membrane. Partial differential equations were solved to yield an equation for the fraction absorbed from gut to the blood. Effects of inhibition of CYP3A4 and/or P-gp on the fraction absorbed were simulated for a hypothetical substrate for both CYP3A4 and P-gp.
Results. The fraction absorbed after oral administration was shown to increase following inhibition of P-gp. This increase was more marked when the efflux clearance of the drug was greater than the sum of the metabolic and absorption clearances and when the intracellular diffusion constant was small. Furthermore, it was demonstrated that the fraction absorbed was synergistically elevated by simultaneous inhibition of both CYP3A4 and P-gp.
Conclusions. The analysis using our present diffusion model is expected to allow the prediction of in vivo intestinal drug absorption and related drug interactions from in vitro studies using human intestinal microsomes, gut epithelial cells, CYP3A4-expressed Caco-2 cells, etc.
- リンク情報
- ID情報
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- DOI : 10.1023/A:1018872207437
- ISSN : 0724-8741
- Web of Science ID : WOS:000079145600009