0000000000466836
AUTHOR
Christer Tannergren
The effects of three absorption-modifying critical excipients on the in vivo intestinal absorption of six model compounds in rats and dogs.
Pharmaceutical excipients that may affect gastrointestinal (GI) drug absorption are called critical pharmaceutical excipients, or absorption-modifying excipients (AMEs) if they act by altering the integrity of the intestinal epithelial cell membrane. Some of these excipients increase intestinal permeability, and subsequently the absorption and bioavailability of the drug. This could have implications for both the assessment of bioequivalence and the efficacy of the absorption-enhancing drug delivery system. The absorption-enhancing effects of AMEs with different mechanisms (chitosan, sodium caprate, sodium dodecyl sulfate (SDS)) have previously been evaluated in the rat single-pass intestin…
In vivo methods for drug absorption - comparative physiologies, model selection, correlations with in vitro methods (IVIVC), and applications for formulation/API/excipient characterization including food effects.
This review summarizes the current knowledge on anatomy and physiology of the human gastrointestinal tract in comparison with that of common laboratory animals (dog, pig, rat and mouse) with emphasis on in vivo methods for testing and prediction of oral dosage form performance. A wide range of factors and methods are considered in addition, such as imaging methods, perfusion models, models for predicting segmental/regional absorption, in vitro in vivo correlations as well as models to investigate the effects of excipients and the role of food on drug absorption. One goal of the authors was to clearly identify the gaps in today's knowledge in order to stimulate further work on refining the e…
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
Three Physiologically Based Pharmacokinetic software packages (GI-Sim, Simcyp® Simulator, and GastroPlus™) 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 (Foral) was underpredicted for compounds with low permeability, suggesting improper estimates of intestinal surface area, colonic absorption and/or lack of intestinal transporter information. Foral was also underpredicted for acidic compounds, suggesting overestimation of impact of ionisation on pe…
IMI – Oral biopharmaceutics tools project – Evaluation of bottom-up PBPK prediction success part 4: Prediction accuracy and software comparisons with improved data and modelling strategies
Oral drug absorption is a complex process depending on many factors, including the physicochemical properties of the drug, formulation characteristics and their interplay with gastrointestinal physiology and biology. Physiological-based pharmacokinetic (PBPK) models integrate all available information on gastro-intestinal system with drug and formulation data to predict oral drug absorption. The latter together with in vitro-in vivo extrapolation and other preclinical data on drug disposition can be used to predict plasma concentration-time profiles in silico. Despite recent successes of PBPK in many areas of drug development, an improvement in their utility for evaluating oral absorption i…
Preclinical Effect of Absorption Modifying Excipients on Rat Intestinal Transport of Model Compounds and the Mucosal Barrier Marker 51Cr-EDTA
There is a renewed interest from the pharmaceutical field to develop oral formulations of compounds, such as peptides, oligonucleotides, and polar drugs. However, these often suffer from insufficient absorption across the intestinal mucosal barrier. One approach to circumvent this problem is the use of absorption modifying excipient(s) (AME). This study determined the absorption enhancing effect of four AMEs (sodium dodecyl sulfate, caprate, chitosan, N-acetylcysteine) on five model compounds in a rat jejunal perfusion model. The aim was to correlate the model compound absorption to the blood-to-lumen clearance of the mucosal marker for barrier integrity, 51Cr-EDTA. Sodium dodecyl sulfate a…
IMI – Oral biopharmaceutics tools project – Evaluation of bottom-up PBPK prediction success part 2: An introduction to the simulation exercise and overview of results
Orally administered drugs are subject to a number of barriers impacting bioavailability (Foral), 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®, and GastroPlus™) 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 exer…