Development, current applications and future roles of biorelevant two-stage in vitro testing in drug development

Parameterization of Physiologically Based Biopharmaceutics Models: Workshop Summary Report

This Article shares the proceedings from the August 29th, 2023 (day 1) workshop "Physiologically Based Biopharmaceutics Modeling (PBBM) Best Practices for Drug Product Quality: Regulatory and Industry Perspectives". The focus of the day was on model parametrization; regulatory authorities from Canada, the USA, Sweden, Belgium, and Norway presented their views on PBBM case studies submitted by industry members of the IQ consortium. The presentations shared key questions raised by regulators during the mock exercise, regarding the PBBM input parameters and their justification. These presentations also shed light on the regulatory assessment processes, content, and format requirements for future PBBM regulatory submissions. In addition, the day 1 breakout presentations and discussions gave the opportunity to share best practices around key questions faced by scientists when parametrizing PBBMs. Key questions included measurement and integration of drug substance solubility for crystalline vs amorphous drugs; impact of excipients on apparent drug solubility/supersaturation; modeling of acid-base reactions at the surface of the dissolving drug; choice of dissolution methods according to the formulation and drug properties with a view to predict the in vivo performance; mechanistic modeling of in vitro product dissolution data to predict in vivo dissolution for various patient populations/species; best practices for characterization of drug precipitation from simple or complex formulations and integration of the data in PBBM; incorporation of drug permeability into PBBM for various routes of uptake and prediction of permeability along the GI tract.

NEW MATHEMATICAL MODEL FROM DYNAMIC DISSOLUTION RATE TESTS

In vitro dissolution experiments are becoming increasingly complex attempting to replicate in vivo behavior. The objective of these new methods is to explore the behavior of low-solubility drugs. This is more relevant for drugs classified in subclasses 2a, 2b and 2c of the BCS, considering their pH-dependent solubility and dissolution characteristics. A novel mathematical approach using a modified double Weibull equation is proposed to model the dissolution and precipitation kinetics observed in two-stage and transfer dissolution experiments (dumping test). This approach demonstrates a high level of accuracy in fitting experimental data for two drugs BCS class 2a and two BCS class 2b, providing valuable insights into their dissolution behavior under different conditions. The results highlight the versatility of the proposed model in capturing complex dissolution phenomena, including rapid dissolution, precipitation, and redissolution. The ease of implementation in Excel, using the Solver tool, makes it a practical and accessible tool for pharmaceutical researchers. Overall, the study contributes to the development of more effective in vitro dissolution testing methods, facilitating the formulation and optimization of pharmaceutical products and potentially aiding in the establishment of in vitro-in vivo correlations (IVIVC).

Best Practices for Integration of Dissolution Data into Physiologically Based Biopharmaceutics Models (PBBM): A Biopharmaceutics Modeling Scientist Perspective

Dissolution is considered as a critical input into physiologically based biopharmaceutics models (PBBM) as it governs in vivo exposure. Despite many workshops, initiatives by academia, industry, and regulatory, wider practices are followed for dissolution data input into PBBM models. Due to variety of options available for dissolution data input into PBBM models, it is important to understand pros, cons, and best practices while using specific dissolution model. This present article attempts to summarize current understanding of various dissolution models and data inputs in PBBM software's and aims to discuss practical challenges and ways to overcome such scenarios. Different approaches to incorporate dissolution data for immediate, modified, and delayed release formulations are discussed in detail. Common challenges faced during fitting of z-factor are discussed along with novel approach of dissolution data incorporation using P-PSD model. Ways to incorporate dissolution data for MR formulations using Weibull and IVIVR approaches were portrayed with examples. Strategies to incorporate dissolution data for DR formulations was depicted along with practical aspects. Approaches to generate virtual dissolution profiles, using Weibull function, DDDPlus, and time scaling for defining dissolution safe space, and strategies to generate virtual dissolution profiles for justifying single and multiple dissolution specifications were discussed. Finally, novel ways to integrate dissolution data for complex products such as liposomes, data from complex dissolution systems, importance of precipitation, and bio-predictive ability of QC media for evaluation of CBA's impact were discussed. Overall, this article aims to provide an easy guide for biopharmaceutics modeling scientist to integrate dissolution data effectively into PBBM models.

Sustainable Stabilizer-Free Nanoparticle Formulations of Valsartan Using Eudragit® RLPO

The bioavailability of the antihypertensive drug valsartan can be enhanced by various microencapsulation methods. In the present investigation, valsartan-loaded polymeric nanoparticles were manufactured from Eudragit® RLPO using an emulsion-solvent evaporation method. Polyvinyl alcohol (PVA) was found to be a suitable stabilizer for the nanoparticles, resulting in a monodisperse colloid system ranging in size between 148 nm and 162 nm. Additionally, a high encapsulation efficiency (96.4%) was observed. However, due to the quaternary ammonium groups of Eudragit® RLPO, the stabilization of the dispersion could be achieved in the absence of PVA as well. The nanoparticles were reduced in size (by 22%) and exhibited similar encapsulation efficiencies (96.4%). This more cost-effective and sustainable production method reduces the use of excipients and their expected emission into the environment. The drug release from valsartan-loaded nanoparticles was evaluated in a two-stage biorelevant dissolution set-up, leading to the rapid dissolution of valsartan in a simulated intestinal medium. In silico simulations using a model validated previously indicate a potential dose reduction of 60-70% compared to existing drug products. This further reduces the expected emission of the ecotoxic compound into the environment.

Increasing the Robustness of Biopharmaceutical Precipitation Assays - Part II: Recommendations on the use of FaSSIF

Biopharmaceutical precipitation assays are an important in vitro tool to characterize the precipitation behavior of weakly basic drugs during their transit from the stomach into the small intestine. To mimic the intestinal fluids more closely, biorelevant media like Fasted State Simulated Intestinal Fluid (FaSSIF) and versions thereof are often applied. When applying UV analytics to measure the drug concentration during the transfer experiments, changes in the UV spectrum of the medium have been observed when FaSSIF was stored over a longer period of time or under accelerated conditions. Therefore, this study aimed at evaluating the stability of FaSSIF under various storage conditions. Furthermore, the impact of stressed FaSSIF on the supersaturation and precipitation behavior of ketoconazole was investigated. As a result of this study, it was demonstrated that the FaSSIF powder composition changes during storage, which, in turn, impacts the supersaturation and precipitation behavior of ketoconazole in in vitro transfer studies. Based on the results of this study, we provide recommendations on the application of FaSSIF in biopharmaceutical precipitation assays with the aim to increase reproducibility and enhance data reliability for those compounds where changing FaSSIF composition may impact the supersaturation and precipitation behavior.

Prediction of in vivo supersaturation and precipitation of poorly water-soluble drugs: Achievements and aspirations

This review focuses on options available to a pharmaceutical scientist to predict in vivo supersaturation and precipitation of poorly water-soluble drugs. As no single device or system can simulate the complex gastrointestinal environment, a combination of appropriate in vitro tools may be utilized to get optimal predictive information. To address the empirical issues encountered during small-scale and full-scale in vitro predictive testing, theoretical background and relevant case studies are discussed. The practical considerations for selection of appropriate tools at various stages of drug development are recommended. Upcoming technologies that have potential to further reduce in vivo studies and expedite the drug development process are also discussed.

Impact of Food and Drink Administration Vehicles on Paediatric Formulation Performance Part 2: Dissolution of Montelukast Sodium and Mesalazine Formulations

Paediatric medicines are not always age-appropriate, causing problems with dosing, acceptability and adherence. The use of food and drinks as vehicles for medicine co-administration is common practice, yet the impact on drug bioavailability, safety and efficacy remains unaddressed. The aim of this study was to use in vitro dissolution testing, under infant simulating conditions, to evaluate the effect of co-administration with vehicles on the dissolution performance of two poorly soluble paediatric drugs. Dissolution studies of mesalazine and montelukast formulations were conducted with mini-paddle apparatus on a two-stage approach: simulated gastric fluid followed by addition of simulated intestinal fluid. The testing scenarios were designed to reflect daily administration practices: direct administration of formulation; formulation co-administered with food and drinks, both immediately after mixing and 4 h after mixing. Drug dissolution was significantly affected by medicine co-administration with vehicles, compared to the direct administration of formulation. Furthermore, differences were observed on drug dissolution when the formulations were mixed with different vehicles of the same subtype. The time between preparation and testing of the drug-vehicle mixture also impacted dissolution behaviour. Drug dissolution was shown to be significantly affected by the physicochemical properties and composition of the vehicles, drug solubility in each vehicle and drug/formulation characteristics. Ultimately, in this study, we show the potential of age-appropriate in vitro dissolution testing as a useful biopharmaceutical tool for estimating drug dissolution in conditions relevant to the paediatric population. The setup developed has potential to evaluate the impact of medicine co-administration with vehicles on paediatric formulation performance.

In Vitro Biopredictive Methods: A Workshop Summary Report

This workshop report summarizes the proceedings of Day 1 of a three-day workshop on "Current State and Future Expectations of Translational Modeling Strategies to Support Drug Product Development, Manufacturing Changes and Controls". Physiologically based biopharmaceutics models (PBBM) are tools which enable the drug product quality attributes to be linked to the in vivo performance. These tools rely on key quality inputs in order to provide reliable predictions. After introducing the objectives of the workshop and the expectations from the breakout sessions, Day 1 of the workshop focused on the best practices and challenges in measuring in vitro inputs needed for modeling, such as the drug solubility, the dissolution rate of the drug product, potential precipitation of the drug and drug permeability. This paper reports the podium presentations and summarizes breakout session discussions related to A) the best strategies for determining solubility, supersaturation and critical supersaturation; B) the best strategies for the development of biopredictive (clinically relevant) dissolution methods; C) the challenges associated with describing gastro-intestinal systems parameters such as mucus, liquid volume and motility; and D) the challenges with translating biopharmaceutical measures of drug permeability along the gastrointestinal tract to a meaningful model parameter.

Multi-dose oral abuse deterrent formulation of loperamide using hot melt extrusion

Loperamide, an over the counter anti-diarrheal drug, also infamously referred to as "poor man's methadone". Due to the ease of availability and low price, people/patients abuse it by consuming more than 30 tablets to achieve euphoric effect and to combat opioid withdrawal. But supratherapeutic doses of loperamide result in severe respiratory depression, cardiac dysrhythmia and mortality. To address this issue, we developed a unique and innovative technology to deter multi-dose oral abuse. The concept is to design a tablet which can immediate release loperamide in diarrheic patients (single tablet) while stops loperamide release in case of intentional multi-dose ingestion. Loperamide was molecularly dispersed into gastric soluble cationic polymers - Eudragit® EPO and Kollicoat® Smartseal 100P using hot melt extrusion to obtain filament. Filaments were milled and compressed into tablets ((Eudragit® EPO (SJU1) and Kollicoat® Smartseal (SJU2)) with optimized amount of L-Arginine. Dissolution in 250 mL of Fasted state simulated gastric fluid (FaSSGF) revealed that single tablet of Imodium® (marketed formulation) and SJU1 showed >85% of release within 15 min. Most importantly, in multi-unit dissolution (15 tablets), Imodium® exhibited >90% release but SJU tablets showed <2% of drug release thus demonstrating its ability to deter multi-dose oral abuse.

Automated small-scale in vitro transfer model as screening tool for the prediction of in vivo-dissolution and precipitation of poorly solubles

Precipitation testing, especially for weakly basic APIs, represents a key parameter in drug substance characterization during early development stages, where the amount of API available is limited. Therefore, it was the aim of this study to develop an automated small-scale in vitro transfer model to characterize the supersaturation and precipitation behavior of two poorly water-soluble drugs. Following automation and scale-down of the standard transfer model, the developed small-scale model was used to assess the impact of gastrointestinal variability, i.e. gastric pH, gastric emptying, and gastrointestinal fluid volumes, on supersaturation and precipitation of two weakly basic model compounds, ketoconazole and a new chemical entity from the research laboratories of Merck KGaA, MSC-A. The experiments revealed that variations in gastrointestinal parameters affected the in vitro behavior of ketoconazole, but not of MSC-A. Elevated gastric pH, as it can result from co-medication with acid-reducing drugs, resulted in lower degrees of supersaturation for both substances. This result is in agreement with the observation that the oral bioavailability of ketoconazole is lowered when proton pump inhibitors are co-administered. The small-scale transfer model presented herein represents a valuable in vitro tool to assess the risk of drug precipitation, additionally covering a broad range of gastrointestinal parameters.