1.
Olivares-Morales, Andres, et al.
(author)
Translating Human Effective Jejunal Intestinal Permeability to Surface-Dependent Intrinsic Permeability : a Pragmatic Method for a More Mechanistic Prediction of Regional Oral Drug Absorption
2015
In: AAPS Journal. - : Springer Science and Business Media LLC. - 1550-7416. ; 17:5, s. 1177-1192
Journal article (peer-reviewed) abstract
Regional intestinal effective permeability (P-eff) values are key for the understanding of drug absorption along the whole length of the human gastrointestinal (GI) tract. The distal regions of the GI tract (i.e. ileum, ascending-transverse colon) represent the main sites for GI absorption when there is incomplete absorption in the upper GI tract, e.g. for modified release formulations. In this work, a new and pragmatic method for the estimation of (passive) intestinal permeability in the different intestinal regions is being proposed, by translating the observed differences in the available mucosal surface area along the human GI tract into corrections of the historical determined jejunal P-eff values. These new intestinal Peff values or "intrinsic" P-eff(P-eff,P-int) were subsequently employed for the prediction of the ileal absorption clearance (CLabs,ileum) for a set of structurally diverse compounds. Additionally, the method was combined with a semi-mechanistic absorption PBPK model for the prediction of the fraction absorbed (f(abs)). The results showed that Peff, int can successfully be employed for the prediction of the ileal CLabs and the f(abs). P-eff,P-int also showed to be a robust predictor of the f(abs) when the colonic absorption was allowed in the PBPK model, reducing the overprediction of f(abs) observed for lowly permeable compounds when using the historical P-eff values. Due to its simplicity, this approach provides a useful alternative for the bottom-up prediction of GI drug absorption, especially when the distal GI tract plays a crucial role for a drug's GI absorption.
2.
Darwich, Adam S., et al.
(author)
IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 3 : Identifying gaps in system parameters by analysing In Silico performance across different compound classes
2017
In: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 96, s. 626-642
Journal article (peer-reviewed) abstract
Three Physiologically Based Pharmacokinetic software packages (GI-Sim, Simcyp (R) Simulator, and GastroPlus (TM)) were evaluated as part of the Innovative Medicine Initiative Oral Biopharmaceutics Tools project (OrBiTo) during a blinded "bottom-up" anticipation of human pharmacokinetics. After data analysis of the predicted vs. measured pharmacokinetics parameters, it was found that oral bioavailability (F-oral) was underpredicted for compounds with low permeability, suggesting improper estimates of intestinal surface area, colonic absorption and/or lack of intestinal transporter information. Foralwas also underpredicted for acidic compounds, suggesting overestimation of impact of ionisation on permeation, lack of information on intestinal transporters, or underestimation of solubilisation of weak acids due to less than optimal intestinal model pH settings or underestimation of bile micelle contribution. F-oral was overpredicted for weak bases, suggesting inadequate models for precipitation or lack of in vitro precipitation information to build informed models. Relative bioavailability was underpredicted for both high logP compounds as well as poorly water-soluble compounds, suggesting inadequate models for solubility/dissolution, underperforming bile enhancement models and/or lack of biorelevant solubility measurements. These results indicate areas for improvement in model software, modelling approaches, and generation of applicable input data. However, caution is required when interpreting the impact of drug-specific properties in this exercise, as the availability of input parameters was heterogeneous and highly variable, and the modellers generally used the data "as is" in this blinded bottom-up prediction approach.
3.
Margolskee, Alison, et al.
(author)
IMI - oral biopharmaceutics tools project - evaluation of bottom-up PBPK prediction success part 1 : Characterisation of the OrBiTo database of compounds
2017
In: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 96, s. 598-609
Journal article (peer-reviewed) abstract
Predicting oral bioavailability (F-oral) is of importance for estimating systemic exposure of orally administered drugs. Physiologically-based pharmacokinetic (PBPK) modelling and simulation have been applied extensively in biopharmaceutics recently. The Oral Biopharmaceutical Tools (OrBiTo) project (Innovative Medicines Initiative) aims to develop and improve upon biopharmaceutical tools, including PBPK absorption models. A large-scale evaluation of PBPK models may be considered the first step. Here we characterise the OrBiTo active pharmaceutical ingredient (API) database for use in a large-scale simulation study. The OrBiTo database comprised 83 APIs and 1475 study arms. The database displayed a median logP of 3.60 (2.40-4.58), human blood-to-plasma ratio of 0.62 (0.57-0.71), and fraction unbound in plasma of 0.05 (0.01-0.17). The database mainly consisted of basic compounds (48.19%) and Biopharmaceutics Classification System class II compounds (55.81%). Median human intravenous clearance was 16.9 L/h (interquartile range: 11.6-43.6 L/h; n = 23), volume of distribution was 80.8 L (54.5-239 L; n = 23). The majority of oral formulations were immediate release (IR: 87.6%). Human Foral displayed a median of 0.415 (0.203-0.724; n = 22) for IR formulations. The OrBiTo database was found to be largely representative of previously published datasets. 43 of the APIs were found to satisfy the minimum inclusion criteria for the simulation exercise, and many of these have significant gaps of other key parameters, which could potentially impact the interpretability of the simulation outcome. However, the OrBiTo simulation exercise represents a unique opportunity to perform a large-scale evaluation of the PBPK approach to predicting oral biopharmaceutics.
4.
Margolskee, Alison, et al.
(author)
IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 2 : An introduction to the simulation exercise and overview of results
2017
In: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 96, s. 610-625
Journal article (peer-reviewed) abstract
Orally administered drugs are subject to a number of barriers impacting bioavailability (F-oral), causing challenges during drug and formulation development. Physiologically-based pharmacokinetic (PBPK) modelling can help during drug and formulation development by providing quantitative predictions through a systems approach. The performance of three available PBPK software packages (GI-Sim, Simcyp (R), and GastroPlus (TM)) were evaluated by comparing simulated and observed pharmacokinetic (PK) parameters. Since the availability of input parameters was heterogeneous and highly variable, caution is required when interpreting the results of this exercise. Additionally, this prospective simulation exercise may not be representative of prospective modelling in industry, as API information was limited to sparse details. 43 active pharmaceutical ingredients (APIs) from the OrBiTo database were selected for the exercise. Over 4000 simulation output files were generated, representing over 2550 study arm-institution-software combinations and approximately 600 human clinical study arms simulated with overlap. 84% of the simulated study arms represented administration of immediate release formulations, 11% prolonged or delayed release, and 5% intravenous (i.v.). Higher percentages of i.v. predicted area under the curve (AUC) were within two-fold of observed (52.9%) compared to per oral (p.o.) (37.2%), however, F-oral and relative AUC (F-rel) between p.o. formulations and solutions were generally well predicted (64.7% and 75.0%). Predictive performance declined progressing from i.v. to solution and immediate release tablet, indicating the compounding error with each layer of complexity. Overall performance was comparable to previous large-scale evaluations. A general overprediction of AUC was observed with average fold error (AFE) of 1.56 over all simulations. AFE ranged from 0.0361 to 64.0 across the 43 APIs, with 25 showing overpredictions. Discrepancies between software packages were observed for a few APIs, the largest being 606, 171, and 81.7-fold differences in AFE between SimCYP and GI-Sim, however average performance was relatively consistent across the three software platforms.
