2007
DOI: 10.2174/138920007782109733
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Prediction of Intestinal First-Pass Drug Metabolism

Abstract: Despite a lower content of many drug metabolising enzymes in the intestinal epithelium compared to the liver (e.g. intestinal CYP3A abundance in the intestine is 1% that of the liver), intestinal metabolic extraction may be similar to or exceed hepatic extraction. Modelling of events on first-pass through the intestine requires attention to the complex interplay between passive permeability, active transport, binding, relevant blood flows and the intrinsic activity and capacity of enzyme systems. We have compa… Show more

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Cited by 333 publications
(364 citation statements)
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“…The Advance Dissolution Absorption and Metabolism (ADAM) model was used if the compound had characteristics suggesting solubility rate-limited absorption and information was available on the type of formulation, pH-solubility profile, dissolution and other pharmaceutical factors such as the supersaturation ratio and precipitation rate. Unless information was available suggesting otherwise, parameters determining gut metabolism such as f uGut (unbound fraction within the enterocyte) and Q gut (nominal flow from gut model [17]), were assumed to be 1 (for f uGut ) and predicted within Simcyp W (for Q gut ).…”
Section: Prediction Of Absorptionmentioning
confidence: 99%
“…The Advance Dissolution Absorption and Metabolism (ADAM) model was used if the compound had characteristics suggesting solubility rate-limited absorption and information was available on the type of formulation, pH-solubility profile, dissolution and other pharmaceutical factors such as the supersaturation ratio and precipitation rate. Unless information was available suggesting otherwise, parameters determining gut metabolism such as f uGut (unbound fraction within the enterocyte) and Q gut (nominal flow from gut model [17]), were assumed to be 1 (for f uGut ) and predicted within Simcyp W (for Q gut ).…”
Section: Prediction Of Absorptionmentioning
confidence: 99%
“…An F >85% indicates high permeability. If F is <85%, then F a can be estimated using the observed clinical data and in vitro results 14, 15. However, in vitro estimates of permeability used in such estimations are limited by the variability between studies, which in turn reflects on the quantitative prediction of F a and represents a great challenge for in vitro ‐ in vivo extrapolations.…”
mentioning
confidence: 99%
“…As cytochrome P450 3A (CYP3A) comprises a large percentage of intestinal CYP enzymes [1], CYP3A substrates are most affected by gut metabolism. However, at the discovery stage, where metabolism of an investigational drug is not yet fully characterized and in the absence of clinical data, F g has to be predicted using pragmatic approaches such as the 'Q gut ' model [2]. The Q gut model uses the 'well-stirred' liver model of hepatic drug clearance to describe F g but the flow term Q gut is a hybrid of both permeability through the enterocyte membrane and villous blood flow [3].…”
mentioning
confidence: 99%
“…The Q gut model uses the 'well-stirred' liver model of hepatic drug clearance to describe F g but the flow term Q gut is a hybrid of both permeability through the enterocyte membrane and villous blood flow [3]. (2) where fu gut is the fraction of drug unbound in the enterocyte, and CLu int,gut is the net intrinsic metabolic clearance in the gut based on the unbound drug concentration. While fu gut cannot be measured experimentally, it can be an important parameter in quantifying the first-pass effect in the gut [2].…”
mentioning
confidence: 99%
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