Usefulness of the Beagle Model in the Evaluation of Paracetamol and Ibuprofen Exposure after Oral Administration to Pediatric Populations: An Exploratory Study

High-performance PBPK model for predicting CYP3A4 induction-mediated drug interactions: a refined and validated approach

Introduction

The cytochrome P450 enzyme 3A4 (CYP3A4) mediates numerous drug-drug interactions (DDIs) by inducing the metabolism of co-administered drugs, which can result in reduced therapeutic efficacy or increased toxicity. This study developed and validated a Physiologically Based Pharmacokinetic (PBPK) model to predict CYP3A4 induction-mediated DDIs, focusing on the early stages of clinical drug development.

Methods

The PBPK model for rifampicin, a potent CYP3A4 inducer, was developed and validated using human pharmacokinetic data. Subsequently, PBPK models for 'victim' drugs were constructed and validated. The PBPK-DDI model's predictive performance was assessed by comparing predicted area under the curve (AUC) and maximum concentration (Cmax) ratioswith empirical data, using both the 0.5 to 2-fold criterion and theGuest criteria.

Results

The rifampicin PBPK model accurately simulated human pharmacokinetic profiles. The PBPK-DDI model demonstrated high predictive accuracy for AUC ratios, with 89% of predictions within the 0.5 to 2-fold criterion and 79% meeting the Guest criteria. For Cmax ratios, an impressive 93% of predictions were within the acceptable range. The model significantly outperformed the static model, particularly in estimating DDI risks associated with CYP3A4 induction.

Discussion

The PBPK-DDI model is a reliable tool for predicting CYP3A4 induction-mediated DDIs. Its high predictive accuracy, confirmed by adherence to evaluation standards, affirms its reliability for drug development and clinical pharmacology. Future refinements may further enhance its predictive value.

The use of population pharmacokinetics to extrapolate food effects from human adults and beagle dogs to the pediatric population illustrated with ibuprofen as a case

Oral drug administration is the most convenient route of administration in the pediatric population. However, children are often not fasted when drugs are orally administered, hence potential food-drug interactions might occur. Most of these interactions are extrapolated from studies performed in human adults where a recommended high-fat, high-calorie meal is administered prior to drug dosing. As the recommended protocols are based on studies in support of adult drug development, these studies do not mimic the meal composition administered to the pediatric population, especially the very young ones, which renders food-drug interactions in this population understudied. Therefore, it was evaluated to what extent population pharmacokinetics could reliably extrapolate food effects from human adults and beagle dogs to mimic the real-life situation in the pediatric population. Eight human adults and six beagle dogs received ibuprofen under different dosing conditions (fasted, reference meal fed condition, infant formula fed condition). Population pharmacokinetic analysis was performed to derive the pharmacokinetic parameters to be scaled to pediatric ages. For both species, a one-compartment model best described the data, where in human adults a dual-input function to capture the double absorption peak significantly improved the model fit. Simulations for a virtual pediatric population demonstrated that the predictive ability of human adults and beagle dogs to inform absorption effects under different dosing conditions using population pharmacokinetic modeling appeared to be reasonable. However, to be able to fully validate the predictability of both species for ibuprofen, additional studies in the pediatric population are required to generate more informative data.

Establishing Virtual Bioequivalence and Clinically Relevant Specifications for Omeprazole Enteric-Coated Capsules by Incorporating Dissolution Data in PBPK Modeling

Currently, Biopharmaceutics Classification System (BCS) classes I and III are the only biological exemptions of immediate-release solid oral dosage forms eligible for regulatory approval. However, through virtual bioequivalence (VBE) studies, BCS class II drugs may qualify for biological exemptions if reliable and validated modeling is used. Here, we sought to establish physiologically based pharmacokinetic (PBPK) models, in vitro-in vivo relationship (IVIVR), and VBE models for enteric-coated omeprazole capsules, to establish a clinically-relevant dissolution specification (CRDS) for screening BE and non-BE batches, and to ultimately develop evaluation criteria for generic omeprazole enteric-coated capsules. To establish omeprazole's IVIVR based on the PBPK model, we explored its in vitro dissolution conditions and then combined in vitro dissolution profile studies with in vivo clinical trials. The predicted omeprazole pharmacokinetics (PK) profiles and parameters closely matched the observed PK data. Based on the VBE results, the bioequivalence study of omeprazole enteric-coated capsules required at least 48 healthy Chinese subjects. Based on the CRDS, the capsules' in vitro dissolution should not be < 28%-54%, < 52%, or < 80% after two, three, and six hours, respectively. Failure to meet these dissolution criteria may result in non-bioequivalence. Here, PBPK modeling and IVIVR methods were used to bridge the in vitro dissolution of the drug with in vivo PK to establish the BE safety space of omeprazole enteric-coated capsules. The strategy used in this study can be applied in BE studies of other BCS II generics to obtain biological exemptions and accelerate drug development.

The Use of Population Pharmacokinetics to Extrapolate Food Effects from Human Adults and Beagle Dogs to the Pediatric Population Illustrated with Paracetamol as a Test Case

To date, food-drug interactions in the pediatric population remain understudied. The current food effect studies are mostly performed in adults and do not mimic the real-life situation in the pediatric population. Since the potential benefits of food effect studies performed in pediatrics should be counterbalanced with the burden that these studies pose to the patients, alternative research strategies should be evaluated. The present study aimed to evaluate whether population pharmacokinetics (popPK) using data in beagle dogs and human adults could reliably assess food effects relevant for the pediatric population. PopPK was utilized to understand the performance of paracetamol under different dosing conditions (when the participants were fasted, with a reference meal, and with infant formula) in human adults (n = 8) and beagle dogs (n = 6) by constructing models to derive the pharmacokinetic parameters and to evaluate the food effects in both species. A two-compartment model with a single input function for the absorption phase best described the profiles of paracetamol in the beagle dogs. In the human adults, a one-compartment model with a dual input function for the absorption phase best described the data. The simulated profiles for the different dosing conditions demonstrated that both the human adults' and beagle dogs' simulations were able to acceptably describe the plasma concentration-time profiles of paracetamol observed in a representative pediatric population, which opens up perspectives on pediatric-relevant food effect predictions. However, the obtained results should be carefully interpreted, since an accurate validation of these findings was not possible due to the scarcity of the literature on observed pediatric data.