Data on Gastroenterology Reported by Researchers at Vertex Pharmaceuticals Inc. (Quantitative Prediction of CYP3A4 Induction: Impact of Measured, Free, and Intracellular Perpetrator Concentrations from Human Hepatocyte Induction Studies on ...)
By a News Reporter-Staff News Editor at Gastroenterology Week -- Investigators discuss new findings in Gastroenterology. According to news reporting out of Boston, Massachusetts, by NewsRx editors, research stated, "Typically, concentration-response curves are based upon nominal inducer concentrations for in-vitro-to-in-vivo extrapolation of CYP3A4 induction. The limitation of this practice is that it assumes the hepatocyte culture model is a static system."
Our news journalists obtained a quote from the research from Vertex Pharmaceuticals Inc., "We assessed whether correcting for: 1) changes in perpetrator concentration in the induction medium during the incubation period, 2) perpetrator binding to proteins in the induction medium, and 3) nonspecific binding of perpetrator can improve the accuracy of CYP3A4 induction predictions. Of the seven compounds used in this evaluation, significant parent loss and nonspecific binding were observed for rifampicin (29.3-38.3%), pioglitazone (64.3-78.6%), and rosiglitazone (57.1-75.5%). As a result, the free measured EC50 values (EC50u) of pioglitazone, rosiglitazone, and rifampicin were significantly lower than the nominal EC50 values. In general, the accuracy of the induction predictions, using multiple static models, improved when corrections were made for measured medium concentrations, medium protein binding, and nonspecific binding of the perpetrator, as evidenced by 18-29% reductions in the root mean square error. The relative induction score model performed better than the basic static and mechanistic static models, resulting in lower prediction error and no false-positive or false-negative predictions. However, even when the EC50u value was used, the induction prediction for bosentan, which is a substrate of organic anion transporter proteins, was overpredicted by approximately 2-fold."
According to the news editors, the research concluded: "Accounting for the ratio of unbound intracellular concentrations to unbound medium concentrations (K-puu,K-in vitro) (0.5-7.5) and the predicted multiple-dose K-puu,K-in vivo (0.6) for bosentan resulted in induction predictions within 35% of the observed interaction."
For more information on this research see: Quantitative Prediction of CYP3A4 Induction: Impact of Measured, Free, and Intracellular Perpetrator Concentrations from Human Hepatocyte Induction Studies on Drug-Drug Interaction Predictions. Drug Metabolism and Disposition, 2017;45(6):692-705. Drug Metabolism and Disposition can be contacted at: Amer Soc Pharmacology Experimental Therapeutics, 9650 Rockville Pike, Bethesda, MD 20814-3995, USA (see also Gastroenterology).
Our news journalists report that additional information may be obtained by contacting N. Hariparsad, Vertex Pharmaceut Inc, Drug Metab & Pharmacokinet, Boston, MA, United States. Additional authors for this research include P.P. Chothe, J.E. Sager, H. Tsao, A. Moore, L. Laitinen and Y.K. Sun.
Keywords for this news article include: Boston, Massachusetts, United States, North and Central America, Gastroenterology, Drugs and Therapies, Vertex Pharmaceuticals Inc.
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