Food for thought: formulating away the food effect - a PEARRL review

Pharmaceutical approaches for enhancing solubility and oral bioavailability of poorly soluble drugs

High solubility in water and physiological fluids is an indispensable requirement for the pharmacological efficacy of an active pharmaceutical ingredient. Indeed, it is well established that pharmaceutical substances exhibiting limited solubility in water are inclined towards diminished and inconsistent absorption following oral administration, consequently resulting in variability in therapeutic outcomes. The current advancements in combinatorial chemistry and pharmaceutical design have facilitated the creation of drug candidates characterized by increased lipophilicity, elevated molecular size, and reduced aqueous solubility. Undoubtedly, the issue of poorly water-soluble medications has been progressively escalating over recent years. Indeed, 40% of the top 200 oral medications marketed in the United States, 33% of drugs listed in the US pharmacopoeia, 75% of compounds under development and 90% of new chemical entities are insufficiently water-soluble compounds. In order to address this obstacle, formulation scientists employ a variety of approaches, encompassing both physical and chemical methods such as prodrug synthesis, salt formation, solid dispersions formation, hydrotropic substances utilization, solubilizing agents incorporation, cosolvent addition, polymorphism exploration, cocrystal creation, cyclodextrins complexation, lipid formulations, particle size reduction and nanoformulation techniques. Despite the utilization of these diverse approaches, the primary reason for the failure in new drug development persists as the poor aqueous solubility of pharmaceutical compounds. This paper, therefore, delves into the foundational principles that underpin the implementation of various formulation strategies, along with a discussion on the respective advantages and drawbacks associated with each approach. Additionally, a discourse is provided regarding methodological frameworks for making informed decisions on selecting an appropriate formulation strategy to effectively tackle the key challenges posed during the development of a poorly water-soluble drug candidate.

Key Factors for Improving Predictive Accuracy and Avoiding Overparameterization of the PBPK Absorption Model in Food Effect Studies of Weakly Basic Water-Insoluble Compounds in Immediate Release Formulations

Background/Objectives: Physiologically based pharmacokinetic (PBPK) absorption models are instrumental for assessing drug absorption prior to clinical food effect studies, though discrepancies in predictive and actual outcomes are observed. This study focused on immediate release formulations of weakly basic water-insoluble compounds, namely rivaroxaban, ticagrelor, and PB-201, to investigate factors that could improve the predictive accuracy of PBPK models regarding food effects. Methods: Comprehensive in vitro experimental results provided the basis for the development of mechanistic absorption models, which were then combined with mechanistic disposition models to predict the systemic exposure of the model drugs in both fasted and fed states. Results: The developed PBPK models showed moderate to high predictive accuracy for food effects in Caucasian populations. For the Chinese population, the ticagrelor model's initial overestimation of fed-state absorption was addressed by updating the permeability parameters from Caco-2 cell assays to those derived from parallel artificial membrane permeability assays in FaSSIF and FeSSIF media. This refinement was also applied to the rivaroxaban and ticagrelor models, leading to a more accurate representation of absorption in Caucasians. Conclusions: This study highlights the importance of apparent permeability in enhancing the predictive accuracy of PBPK absorption models for weakly basic water-insoluble compounds. Furthermore, the precipitation of PB-201 in the two-stage transfer experiments suggests that precipitation may not be a universal phenomenon for such compounds in vivo. Consequently, the precipitation rate constant, a theoretically essential parameter, should be determined based on experimental evidence to avoid overparameterization and ensure robust predictive accuracy of PBPK models.

Drug Nanocrystals in Oral Absorption: Factors That Influence Pharmacokinetics

Despite the safety and convenience of oral administration, poorly water-soluble drugs compromise absorption and bioavailability. These drugs can exhibit low dissolution rates, variability between fed and fasted states, difficulty permeating the mucus layer, and P-glycoprotein efflux. Drug nanocrystals offer a promising strategy to address these challenges. This review focuses on the opportunities to develop orally administered nanocrystals based on pharmacokinetic outcomes. The impacts of the drug particle size, morphology, dissolution rate, crystalline state on oral bioavailability are discussed. The potential of the improved dissolution rate to eliminate food effects during absorption is also addressed. This review also explores whether permeation or dissolution drives nanocrystal absorption. Additionally, it addresses the functional roles of stabilizers. Drug nanocrystals may result in prolonged concentrations in the bloodstream in some cases. Therefore, nanocrystals represent a promising strategy to overcome the challenges of poorly water-soluble drugs, thus encouraging further investigation into unclear mechanisms during oral administration.

Predicting gastric emptying of drug substances taken under postprandial conditions by combination of biorelevant dissolution and mechanistic in silico modeling

Physiologically based pharmacokinetic (PBPK) models can help to understand the effects of gastric emptying on pharmacokinetics and in particular also provide a platform for understanding mechanisms of food effects, as well as extrapolation between different postprandial conditions, whether standardized clinical or patient-oriented, non-clinical conditions. By integrating biorelevant dissolution data from the GastroDuo dissolution model into a previously described mechanistic model of fed-state gastric emptying, we simulated the effects of a high-calorie high-fat meal on the pharmacokinetics of sildenafil, febuxostat, acetylsalicylic acid, theobromine and caffeine. The model was able to simulate the variability in Cmax and tmax caused by the presence of the stomach road. The main influences investigated to affect the gastric emptying process were drug solubility (theobromine and caffeine), tablet dissolution rate (acetylsalicylic acid) and sensitivity to gastric motility (sildenafil and febuxostat). Finally, we showed how PBPK models can be used to extrapolate pharmacokinetics between different prandial states using theobromine as an example with results from a clinical study being presented.

Rationalizing Counterion Selection for the Development of Lipophilic Salts: A Case Study with Venetoclax

The use of lipid-based formulations (LBFs) can be hindered by low dose loading due to solubility limitations of candidate drugs in lipid vehicles. Formation of lipophilic salts through pairing these drugs with a lipophilic counterion has been demonstrated as a potential means to enhance dose loading in LBFs. This study investigated the screening of appropriate counterions to form lipophilic salts of the BCS class IV drug venetoclax. The physical properties, lipid solubility, and in vitro performance of the salts were analyzed. This study illustrated the versatility of alkyl sulfates and sulfonates as suitable counterions in lipophilic salt synthesis with up to ∼9-fold higher solubility in medium- and long-chain LBFs when compared to that of the free base form of venetoclax. All salts formulated as LBFs displayed superior in vitro performance when compared to the free base form of the drug due to the higher initial drug loadings in LBFs and increased affinity for colloidal species. Further, in vitro studies confirmed that venetoclax lipophilic salt forms using alkyl chain counterions demonstrated comparable in vitro performance to venetoclax docusate, thus reducing the potential for laxative effects related to docusate administration. High levels of the initial dose loading of venetoclax lipophilic salts were retained in a molecularly dispersed state during dispersion and digestion of the formulation, while also demonstrating increased levels of saturation in biorelevant media. The findings of this study suggest that alkyl chain sulfates and sulfonates can act as a suitable alternative counterion to docusate, facilitating the selection of counterions that can unlock the potential to formulate venetoclax as an LBF.

The effect of food on the pharmacokinetics of Sutetinib maleate capsule, an irreversible EGFR tyrosine kinase inhibitor, in healthy Chinese subjects

Sutetinib is an irreversible inhibitor of epidermal growth factor receptor (EGFR) and showed favorable efficacy and safety in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harbouring nondrug-resistant rare EGFR mutations. To evaluate the potential food effect, eighteen healthy Chinese subjects were enrolled in a single-centre, randomized, open-label, two-sequence, two-period crossover study. Sutetinib was administered as a single oral 100 mg under fasting or fed conditions, and pharmacokinetic sampling was performed following each dose and analysed by a validated liquid chromatography/mass spectrometry method. Safety and tolerability were also evaluated. Food intake slightly decreased maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 to infinity (AUC0 - inf) of sutetinib (geometric least-squares mean [GLSM] ratio, 80.94% and 86.11%; 90% confidence interval [CI], 68.43-95.72 and 75.88-97.73) and its active metabolite sutetinib N-Oxide (GLSM ratio, 75.58% and 84.00%; 90% CI, 65.69-86.95 and 75.42-93.56), respectively. In addition, the time to maximum plasma concentration (Tmax) of both sutetinib and its metabolite has been prolonged by 2 h under fed conditions. A total of 31 adverse events (AEs) occurred during the study, with no serious adverse events (SAE) reported, and no obvious difference was observed between the fasting and fed groups. Our results demonstrated that a high-fat and high-calorie diet caused a significant delay in drug absorption and a marginal reduction in drug exposure. Sutetinib was generally well tolerated in healthy Chinese subjects. (This trial was registered at http://www.chinadrugtrials.org.cn . The registration No. is CTR20201933, and the date of registration is 2020-10-16).

Do dietary interventions exert clinically important effects on the bioavailability of β-lactam antibiotics? A systematic review with meta-analyses

BACKGROUND

Managing drug-food interactions may help to achieve the optimal action and safety profile of β-lactam antibiotics.

METHODS

We conducted a systematic review with meta-analyses in adherence to PRISMA guidelines for 32 β-lactams. We included 166 studies assessing the impact of food, beverages, antacids or mineral supplements on the pharmacokinetic (PK) parameters or PK/pharmacodynamic (PK/PD) indices.

RESULTS

Eighteen of 25 β-lactams for which data on food impact were available had clinically important interactions. We observed the highest negative influence of food (AUC or Cmax decreased by >40%) for ampicillin, cefaclor (immediate-release formulations), cefroxadine, cefradine, cloxacillin, oxacillin, penicillin V (liquid formulations and tablets) and sultamicillin, whereas the highest positive influence (AUC or Cmax increased by >45%) for cefditoren pivoxil, cefuroxime and tebipenem pivoxil (extended-release tablets). Significantly lower bioavailability in the presence of antacids or mineral supplements occurred for 4 of 13 analysed β-lactams, with the highest negative impact for cefdinir (with iron salts) and moderate for cefpodoxime proxetil (with antacids). Data on beverage impact were limited to 11 antibiotics. With milk, the extent of absorption was decreased by >40% for cefalexin, cefradine, penicillin G and penicillin V, whereas it was moderately increased for cefuroxime. No significant interaction occurred with cranberry juice for two tested drugs (amoxicillin and cefaclor).

CONCLUSIONS

Factors such as physicochemical features of antibiotics, drug formulation, type of intervention, and patient's health state may influence interactions. Due to the poor actuality and diverse methodology of included studies and unproportionate data availability for individual drugs, we judged the quality of evidence as low.

DDID: a comprehensive resource for visualization and analysis of diet-drug interactions

Diet-drug interactions (DDIs) are pivotal in drug discovery and pharmacovigilance. DDIs can modify the systemic bioavailability/pharmacokinetics of drugs, posing a threat to public health and patient safety. Therefore, it is crucial to establish a platform to reveal the correlation between diets and drugs. Accordingly, we have established a publicly accessible online platform, known as Diet-Drug Interactions Database (DDID, https://bddg.hznu.edu.cn/ddid/), to systematically detail the correlation and corresponding mechanisms of DDIs. The platform comprises 1338 foods/herbs, encompassing flora and fauna, alongside 1516 widely used drugs and 23 950 interaction records. All interactions are meticulously scrutinized and segmented into five categories, thereby resulting in evaluations (positive, negative, no effect, harmful and possible). Besides, cross-linkages between foods/herbs, drugs and other databases are furnished. In conclusion, DDID is a useful resource for comprehending the correlation between foods, herbs and drugs and holds a promise to enhance drug utilization and research on drug combinations.

Evaluation of Food Effect on the Pharmacokinetics of Velufenacin, a New Muscarinic Receptor Antagonist, in Healthy Subjects

Velufenacin (DA-8010) is a new muscarinic receptor antagonist under development for the treatment of overactive bladder. This study aimed to evaluate the effect of food on the pharmacokinetics (PK) and safety of velufenacin in healthy subjects. A randomized, open-label, single-dose, 4-sequence, 4-treatment, 4-period crossover study was conducted. Subjects received a single oral dose of velufenacin 2.5 or 5 mg in a fasted or fed (high-fat meal) state in each period with a 7-day washout. PK parameters including maximum plasma concentration (Cmax ) and area under the concentration-time curve from time 0 to the last measurable point were compared between the fed and fasted states. Twenty-seven subjects completed the study. The mean area under the concentration-time curve from time 0 to the last measurable point of the velufenacin 2.5 and 5 mg doses under the fed condition showed a 1.5- and 1.3-fold increase, respectively, compared to the fasted condition. The corresponding values for Cmax were a 2.3- and 2.0-fold increase, respectively. The time to reach Cmax was comparable regardless of the dose or food intake, showing median values of 4.5-5.0 hours. These results suggest a modest increase of velufenacin absorption by food intake. Velufenacin was generally safe and well tolerated at the 2.5 and 5 mg doses regardless of food.

Safety, Tolerability, and Pharmacokinetics of Valemetostat Tablets and the Effect of Food on Valemetostat Pharmacokinetics in Healthy Subjects: Two Phase 1 Studies

Valemetostat is an oral, selective inhibitor of enhancer of zeste homolog-2 (EZH2) and EZH1. In a first-in-human phase-1 trial, valemetostat capsules were well tolerated and clinically active in patients with relapsed/refractory non-Hodgkin lymphoma. Subsequently, a film-coated tablet formulation was developed for future clinical trials and commercialization. We report outcomes from 2 phase 1 trials in healthy Japanese participants, assessing the safety, tolerability, and pharmacokinetics (PK) of valemetostat tablets at single ascending doses (50, 100, and 200-mg), the relative bioavailability between capsules and tablets, and the effect of food (high-fat or low-fat meals) on the PK of valemetostat tablets. In the ascending-dose study, valemetostat maximum plasma concentration (Cmax ) and area under the concentration-time curve (AUC) increased dose-proportionally. Valemetostat plasma PK parameters were similar between the capsule and tablet formulations following a single 200-mg dose. Administration of valemetostat, 200 mg after a meal, was associated with 50%-60% lower Cmax , 30%-50% lower AUC, and a median Tmax delay of 2.5-3 hours relative to fasted administration. Valemetostat was well tolerated in healthy subjects; treatment-emergent adverse events were mild (grade 1) in severity. Based on these trials, the tablet formulation of valemetostat is suitable for use in subsequent clinical trials and should be administered under fasted conditions to avoid a negative food effect.

Analysis of the interplay of physiological response to food intake and drug properties in food-drug interactions

The effect of food on oral drug absorption is determined by the complex interplay among gut physiological factors and drug properties. The currently used dissolution testing and classification systems (biopharmaceutics classification system, BCS or biopharmaceutics drug disposition classification system, BDDCS) do not account for dynamic changes in gastrointestinal physiology caused by food intake. This study aimed to identify key drug properties that influence food effect (FE) using supervised machine learning approaches. The analysis showed that drugs with high logP, dose number, and extraction ratio have a higher probability of positive FE, while drugs with low permeability and high efflux saturation index have a greater likelihood of negative FE. Weakly acidic drugs also showed a greater probability of positive FE, particularly at pKa >4.3. The importance of drug properties in predicting FE was ranked as logP, dose number, extraction ratio, pKa, and permeability. The accuracy of FE prediction using the models was compared with BCS and extended clearance classification system (ECCS). Overall, the likelihood or magnitude of FE depends on physiological changes to food intake such as altered bile acid secretion rate, intestinal metabolism, transport kinetics, and gastric emptying time, which should be considered along with drug properties (e.g., solubility, logP, and ionization) in predicting FE of orally administered drugs.

In vitro and in silico methods to investigate the effect of moderately increasing medium viscosity and density on ibuprofen dissolution rate

Medium viscosity can affect drug dissolution rate, however, it is not usually considered in routine dissolution testing or less complex biorelevant media. The effects of moderately increasing medium viscosity on the in vitro and in silico dissolution of ibuprofen were investigated with two viscosity enhancing agents (VEA) (hydroxypropyl methylcellulose (HPMC) and sucrose), three viscosity levels (range 0.7-5.5 mPa.s), two solubilities and two fluid velocities in the paddle, flow-through and intrinsic dissolution apparatuses. A factorial design analysis highlighted which factors significantly affected key dissolution metrics. Experimental results in the flow-through apparatus (FTA) were compared with in silico dissolution profiles generated by an in-house simulation code (SIMDISSOTM). Increasing viscosity reduced the intrinsic dissolution rate of ibuprofen for both VEAs. The dissolution rate reduction was also observed in the FTA with sucrose, but less so with HPMC, suggesting particle wetting, motion and surface area effects. Particle motion simulations suggested reduced particle lifting times as viscosity increased, indicating an effect of viscosity on particle dispersal. The viscosity- and fluid density-mediated reduction in the dissolution rate observed with sucrose was accurately simulated by SIMDISSOTM, in particular at higher velocities. Velocity had a significant impact on dissolution rates in the paddle apparatus, with a significant viscosity-related reduction in dissolution observed in the low solubility-low velocity scenario. Even small increases in medium viscosity can reduce the dissolution rate of a BCS class II drug, and in silico particle motion and dissolution data can assist interpretation of particulate dissolution behaviour.

Applications of Modeling and Simulation Approaches in Support of Drug Product Development of Oral Dosage Forms and Locally Acting Drug Products: a Symposium Summary

The number of modeling and simulation applications, including physiologically based pharmacokinetic (PBPK) models, physiologically based biopharmaceutics modeling (PBBM), and empirical models, has been constantly increasing along with the regulatory acceptance of these methodologies. While aiming at minimizing unnecessary human testing, these methodologies are used today to support the development and approval of novel drug products and generics. Modeling approaches are leveraged today for assessing drug-drug interaction, informing dose adjustments in renally or hepatically impaired patients, perform dose selection in pediatrics and pregnant women and diseased populations, and conduct biopharmaceutics-related assessments such as establish clinically relevant specifications for drug products and achieve quality assurance throughout the product life cycle. In the generics space, PBPK analyses are utilized toward virtual bioequivalence assessments within the scope of alternative bioequivalence approaches, product-specific guidance development, and food effect assessments among others. Case studies highlighting the evolving and expanding role of modeling and simulation approaches within the biopharmaceutics space were presented at the symposium titled "Model Informed Drug Development (MIDD): Role in Dose Selection, Vulnerable Populations, and Biowaivers - Chemical Entities" and Prologue "PBPK/PBBM to inform the Bioequivalence Safe Space, Food Effects, and pH-mediated DDIs" at the American Association of Pharmaceutical Scientists (AAPS) PharmSci 360 Annual Meeting in Boston, MA, on October 16-19, 2022, and are summarized here.

Effect of Food on the Pharmacokinetics of Limertinib (ASK120067) and its Main Metabolite in Healthy Chinese Volunteers

Limertinib (ASK120067) is a newly developed third-generation epidermal growth factor receptor tyrosine kinase inhibitor. This phase I, open-label, 2-period crossover study was conducted to evaluate the effect of food on the pharmacokinetics (PK) of limertinib and its active metabolite CCB4580030 in Chinese healthy volunteers (HVs). HVs were randomly assigned (1:1) to receive a single dose of limertinib (160 mg) under the fasted state in period 1 and fed condition in period 2, or vice versa. Twenty-four HVs were enrolled, and 20 HVs completed both study periods. PK were assessed before dosing and ≤72 hours after dosing. PK parameters were analyzed by a noncompartmental method. Limertinib was absorbed faster in the fasted state compared with the fed state. The geometric mean ratios (fed/fast) of maximum concentration, area under the plasma concentration-time curve from time 0 to the last quantifiable concentration, and area under the plasma concentration-time curve from time 0 to infinity for ASK120067 were 145.5%, 145.4%, and 141.9%, respectively. Geometric mean ratios of the PK parameters of CCB4580030 were >125.00% and 90% confidence intervals were outside the preset bioequivalent range. Safety profiles were similar in both prandial states, and limertinib was well tolerated. Food reduced the rate and increased the extent of limertinib absorption following oral administration. Whether limertinib can be administered regardless of prandial state in patients warrants further investigation of efficacy and safety.

Lipid based formulations as supersaturating oral delivery systems: From current to future industrial applications

Lipid-based formulations, in particular supersaturated lipid-based formulations, are important delivery approaches when formulating challenging compounds, as especially low water-soluble compounds profit from delivery in a pre-dissolved state. In this article, the classification of lipid-based formulation is described, followed by a detailed discussion of different supersaturated lipid-based formulations and the recent advances reported in the literature. The supersaturated lipid-based formulations discussed include both the in situ forming supersaturated systems as well as the thermally induced supersaturated lipid-based formulations. The in situ forming drug supersaturation by lipid-based formulations has been widely employed and numerous clinically available products are on the market. There are some scientific gaps in the field, but in general there is a good understanding of the mechanisms driving the success of these systems. For thermally induced supersaturation, the technology is not yet fully understood and developed, hence more research is required in this field to explore the formulations beyond preclinical studies and initial clinical trials.

Cardiovascular Remodeling Post-Ischemia: Herbs, Diet, and Drug Interventions

Cardiovascular disease (CVD) is a serious health burden with increasing prevalence, and CVD continues to be the principal global source of illness and mortality. For several disorders, including CVD, the use of dietary and medicinal herbs instead of pharmaceutical drugs continues to be an alternate therapy strategy. Despite the prevalent use of synthetic pharmaceutical medications, there is currently an unprecedented push for the use of diet and herbal preparations in contemporary medical systems. This urge is fueled by a number of factors, the two most important being the common perception that they are safe and more cost-effective than modern pharmaceutical medicines. However, there is a lack of research focused on novel treatment targets that combine all these strategies-pharmaceuticals, diet, and herbs. In this review, we looked at the reported effects of pharmaceutical drugs and diet, as well as medicinal herbs, and propose a combination of these approaches to target independent pathways that could synergistically be efficacious in treating cardiovascular disease.

Prandial state and biological sex modulate clinically relevant efflux transporters to different extents in Wistar and Sprague Dawley rats

P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2) are clinically relevant efflux transporters implicated in the oral absorption of many food and drug substrates. Here, we hypothesised that food intake could influence protein and mRNA intestinal expression of P-gp/abcb1a, BCRP/abcg2, and MRP2/abcc2 differently in male and female Wistar and Sprague Dawley rats. To test this hypothesis, we used enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR) to quantify the protein and mRNA intestinal expression of these transporters, respectively. Our study found food and sex differences in P-gp expression, whereby in the fed state P-gp expression decreased in male Wistar rats, but P-gp expression increased in females. In the fed state, BCRP expression increased in both male and female Wistar rats, compared with the fasted state. In contrast, no sex differences or food effect differences were seen in Sprague Dawley rats for P-gp and BCRP expression. On the other hand, in the fed state, MRP2 expression was higher in male and female Wistar and Sprague Dawley rats when compared with the fasted state. Sex differences were also observed in the fasted state. Overall, significant strain differences were reported for P-gp, BCRP and MRP2 expression. Strong to moderate positive linear correlations were found between ELISA and PCR quantification methods. ELISA may be more useful than PCR as it reports protein expression as opposed to transcript expression. Researchers must consider the influence of sex, strain and feeding status in preclinical studies of P-gp, BCRP and MRP2 drug substrates.

Assessment of food effects during clinical development

Food-drug interactions frequently hamper oral drug development due to various physicochemical, physiological and formulation-dependent mechanisms. This has stimulated the development of a range of promising biopharmaceutical assessment tools which, however, lack standardized settings and protocols. Hence, this manuscript aims to provide an overview of the general approach and the methodology used in food effect assessment and prediction. For in vitro dissolution-based predictions, the expected food effect mechanism should be carefully considered when selecting the level of complexity of the model, together with its drawbacks and advantages. Typically, in vitro dissolution profiles are then incorporated into physiologically based pharmacokinetic models, which can estimate the impact of food-drug interactions on bioavailability within 2-fold prediction error, at least. Positive food effects related to drug solubilization in the GI tract are easier to predict than negative food effects. Preclinical animal models also provide a good level of food effect prediction, with beagle dogs remaining the gold standard. When solubility-related food-drug interactions have large clinical impact, advanced formulation approaches can be used to improve fasted state pharmacokinetics, hence decreasing the fasted/fed difference in oral bioavailability. Finally, the knowledge from all studies should be combined to secure regulatory approval of the labelling instructions.

Fed Intestinal Solubility Limits and Distributions Applied to the Developability Classification System

For solid oral dosage forms drug solubility in intestinal fluid is an important parameter influencing product performance and bioavailability. Solubility along with permeability are the two parameters applied in the Biopharmaceutics and Developability Classification Systems (DCS) to assess a drug's potential for oral administration. Intestinal solubility varies with the intestinal contents and the differences between the fasted and fed states are recognised to influence solubility and bioavailability. In this study a novel fed state simulated media system comprising of nine media has been utilised to measure the solubility of seven drugs (ibuprofen, mefenamic acid, furosemide, dipyridamole, griseofulvin, paracetamol and acyclovir) previously studied in the fasted state DCS. The results demonstrate that the fed nine media system provides a range of solubility values for each drug and solubility behaviour is consistent with published design of experiment studies conducted in either the fed or fasted state. Three drugs (griseofulvin, paracetamol and acyclovir) exhibit very narrow solubility distributions, a result that matches published behaviour in the fasted state, indicating that this property is not influenced by the concentration of simulated media components. The nine solubility values for each drug can be utilised to calculate a dose/solubility volume ratio to visualise the drug's position on the DCS grid. Due to the derivation of the nine media compositions the range and catergorisation could be considered as bioequivalent and can be combined with the data from the original fed intestinal fluid analysis to provide a population based solubility distribution. This provides further information on the drugs solubility behaviour and could be applied to quality by design formulation approaches. Comparison of the fed results in this study with similar published fasted results highlight that some differences detected match in vivo behaviour in food effect studies. This indicates that a combination of the fed and fasted systems may be a useful in vitro biopharmaceutical performance tool. However, it should be noted that the fed media recipes in this study are based on a liquid meal (Ensure Plus) and this may not be representative of alternative fed states achieved through ingestion of a solid meal. Nevertheless, this novel approach provides greater in vitro detail with respect to possible in vivo biopharmaceutical performance, an improved ability to apply risk-based approaches and the potential to investigate solubility based food effects. The system is therefore worthy of further investigation but studies will be required to expand the number of drugs measured and link the in vitro measurements to in vivo results.

Usefulness of the BioGIT system in screening for differences in early exposure in the fasted state on an a priori basis

The objective of the present study was to confirm the usefulness of BioGIT data in the evaluation of the impact of dose and/or formulation on early exposure after oral administration of immediate release or enabling products of low solubility active pharmaceutical ingredients (APIs) with a glass of water in the fasted state. BioGIT experiments were performed with four APIs: Compound Α (tablet, three dose levels), Compound E (capsule PiC1, capsule PiC2 and tablet), fenofibrate (Lipidil® capsule and Lipidil 145 ONE® tablet) and Compound F (HP-β-CD aqueous solution and tablet). Based on mean plasma AUC_0-60min values which became available after completion of the BioGIT experiments, mean BioGIT AUC_0-50min values were useful for the evaluation of the impact of dose and/or formulation on early exposure. The log-transformed ratios of mean BioGIT AUC_0-50min values for two doses and/or two formulations estimated in this study and in a recent study for two diclofenac potassium products (Cataflam® tablet and Voltfast® sachet, same dose) vs. the corresponding log-transformed ratios of mean plasma AUC_0-60min values (n = 7 pairs of ratios), were included in a previously established correlation between log-transformed ratios of mean BioGIT AUC_0-50min values and log-transformed ratios of plasma AUC_0-60min values (n = 9 pairs of ratios). The correlation between log-transformed plasma AUC_0-60min ratios vs. log-transformed BioGIT AUC_0-50min ratios was confirmed (n = 16 pairs of ratios, R = 0.90). Compared with the previously established correlation the statistical characteristics were improved. Based on this study, the BioGIT system could be useful as a screening tool for assessing the impact of dose and/or formulation differences on early exposure, after administration of immediate release or enabling drug products of low solubility APIs with a glass of water in the fasted state, on an a priori basis.

Bridging the Gap between Food Effects under Clinical Trial Conditions and Real Life: Modeling Delayed Gastric Emptying of Drug Substances and Gastric Content Volume Based on Meal Characteristics

Delayed gastric emptying is known to have a major impact on drug absorption. While the test meal recommended by the FDA and EMA to study food effects represents a worst-case scenario, it does not reflect the reality of the patients. Physiologically based pharmacokinetic (PBPK) models could bridge the gap between clinical settings of food effect studies and the diverse nonclinical situations by simulating the effect of meals with different compositions and volumes. A mathematical equation based on a stretched exponential function was reparameterized to describe the gastric emptying process of mixed solid meals. The model was fitted to literature data including the gastric emptying data of 23 meals from 15 studies. Using a multiple linear regression model, we were able to predict the two function parameters from the meal characteristics caloric content and the percentage of calories derived from fat. After implementation into the PBPK software PK-Sim, the model, together with a separate compartment for liquid gastric contents, was compared to commercially available software. The model is able to simulate the gastric emptying of mixed solid meals containing drugs based on specific meal characteristics. A second compartment allows for distribution between liquid and solid components and rapid gastric emptying along the Magenstrasse.

Population pharmacokinetic/pharmacodynamic models of JNJ-64794964, a toll-like receptor 7 agonist, in healthy adult participants

BACKGROUND

JNJ-4964 is a TLR7 agonist, which, via a type I interferon (IFN)-dependent mechanism, may enhance host immunity suppressed by persistent exposure to hepatitis B antigens in chronic hepatitis B.

METHODS

PK and PD data were pooled from 2 studies involving 90 participants (n = 74 JNJ-4964, dose range 0.2-1.8 mg; n = 16 placebo) in a fasted state. Food effects on PK were studied in 24 participants (1.2 or 1.25 mg). A population PK model and PK/PD models were developed to characterize the effect of JNJ-4964 plasma levels on the time course of IFN-α, IFN-γ-inducible protein 10 (IP-10 or CXCL10), IFN-stimulated gene 15 (ISG15), neopterin and lymphocytes following single and weekly dosing in healthy adults. Covariate effects, circadian rhythms and negative feedback were incorporated in the models.

RESULTS

A 3-compartment linear PK model with transit absorption adequately described JNJ-4964 PK. Bioavailability was 44.2% in fed state relative to fasted conditions. Indirect response models with maximum effect (Emax) stimulation on production rate constant (kin) described IFN-α, IP-10, ISG15 and neopterin, while a precursor-dependent indirect response model with inhibitory effect described the transient lymphocyte reduction. Emax, EC50 and γ (steepness) estimates varied according to PD markers, with EC50 displaying substantial between-subject variability. Female and Asian race exhibited lower EC50, suggesting higher responsiveness.

CONCLUSIONS

PK/PD models well characterized the time course of immune system markers in healthy adults. Our results supported sex and race as covariates on JNJ-4964 responsiveness, as well as circadian rhythms and negative feedback as homeostatic mechanisms that are relevant in TLR7-induced type I IFN responses.

Food effects on gastrointestinal physiology and drug absorption

Food ingestion affects the oral absorption of many drugs in humans. In this review article, we summarize the physiological factors in the gastrointestinal (GI) tract that affect the in vivo performance of orally administered solid dosage forms in fasted and fed states in humans. In particular, we discuss the effects of food ingestion on fluid characteristics (pH, bile concentration, and volume) in the stomach and small intestine, GI transit of water and dosage forms, and microbiota. Additionally, case examples of food effects on GI physiology and subsequent changes in oral drug absorption are provided. Furthermore, the effects of food, especially fruit juices (e.g., grapefruit, orange, apple) and green tea, on transporter-mediated permeation and enzyme-catalyzed metabolism of drugs in intestinal epithelial cells are also summarized comprehensively.

When interactions between bile salts and cyclodextrin cause a negative food effect: Dynamic dissolution/permeation studies with itraconazole (Sporanox®) and biomimetic media

The marketed oral solution of itraconazole (Sporanox®) contains 40% (259.2 mM) of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The obvious role of HP-β-CD is to solubilize itraconazole and to overcome its poor aqueous solubility that restricts its absorption. In this study, we investigated the biorelevance of in vitro experiments by the influence of biomimetic media (containing bile salts and phospholipids) on the predicted itraconazole absorption from the commercial HP-β-CD-based Sporanox® solution. We performed phase-solubility studies of itraconazole and dynamic 2-step-dissolution/permeation studies using a biomimetic artificial barrier, Sporanox® solution, and fasted state simulated intestinal fluid (FaSSIF_V1). Both FaSSIF_V1 and HP-β-CD increased the apparent solubility of itraconazole when used individually. In combination, their solubility-enhancing effects were not additive probably due to the competition of bile salts with itraconazole for the hydrophobic cavity of HP-β-CD. Our combined dissolution/permeation experiments indicated the occurrence of a transient supersaturation from Sporanox® upon two-step dissolution. Through systematic variation of bile salt concentrations in the biomimetic media, it was observed that the extent and the duration of supersaturation depend on the concentrations of bile salts: supersaturation was rather stable in the absence of bile salts and phospholipids. The higher the bile salt concentration, the faster the collapse of the transient supersaturation occurred, an effect which is nicely mirrored by reduced in vitro permeation across the barrier. This is an indication of a negative food effect, which in fact correlates well with what earlier had been observed in clinical studies for Sporanox® solution. In essence, we could demonstrate that in vitro two-stage dissolution/permeation experiments using an artificial barrier and selected biomimetic media may predict the negative effects of the latter on cyclodextrin-based drug formulations like Sporanox® Oral Solution and, at the same time, provide a deeper mechanistic insight.

Pharmacokinetics and Bioequivalence of Single-Oral-Dose Linagliptin: A Randomized, 2-Period Crossover Trial in Chinese Healthy Subjects Under Fasting and Fed Conditions

The bioequivalence of the reference and test linagliptin formulations was assessed in healthy Chinese subjects under fasting and fed conditions. The study was designed as a single-dose, randomized, open-label, 2-period crossover study with a 35-day washout period between 2 administrations. Forty-eight healthy subjects received 5 mg of test and reference linagliptin formulation orally under fasting condition. The geometric mean of the maximum observed linagliptin concentration (C_max ) for the test formulation was 4.9 ng/mL (reference, 5.0 ng/mL), the area under the plasma concentration-time curve from 0 to 72 hours (AUC_0-72 ) was 154.7 ng · h/mL (reference, 157.4 ng · h/mL). Thirty-six subjects received 5 mg of test and reference linagliptin formulation orally under fed conditions. The geometric mean of C_max for the test linagliptin formulation was 2.8 ng/mL (reference, 2.8 ng/mL), AUC_0-72 was 133.5 ng · h/mL (reference, 136.6 ng · h/mL). The 90%CIs for the test/reference ratio for C_max and AUC_0-72 met the bioequivalence criteria (80%-125%). The test and reference formulations of linagliptin were well tolerated and bioequivalent under fasting and fed conditions.

Fast-Fed Variability: Insights into Drug Delivery, Molecular Manifestations, and Regulatory Aspects

Among various drug administration routes, oral drug delivery is preferred and is considered patient-friendly; hence, most of the marketed drugs are available as conventional tablets or capsules. In such cases, the administration of drugs with or without food has tremendous importance on the bioavailability of the drugs. The presence of food may increase (positive effect) or decrease (negative effect) the bioavailability of the drug. Such a positive or negative effect is undesirable since it makes dosage estimation difficult in several diseases. This may lead to an increased propensity for adverse effects of drugs when a positive food effect is perceived. However, a negative food effect may lead to therapeutic insufficiency for patients suffering from life-threatening disorders. This review emphasizes the causes of food effects, formulation strategies to overcome the fast-fed variability, and the regulatory aspects of drugs with food effects, which may open new avenues for researchers to design products that may help to eliminate fast-fed variability.

Comparison of a single pharmaceutical surfactant versus intestinal biorelevant media for etravirine dissolution: Role and impact of micelle diffusivity

Etravirine is an antiviral whose oral absorption is limited by low solubility/dissolution. The objective was to predict and compare etravirine's surfactant-mediated dissolution into polyoxyethylene-10 lauryl ether (POE) and FeSSIF-V2, including the contribution of slow micelle diffusivity. Dynamic light scattering (DLS) was used to measure the size and diffusivity values of drug-loaded micelles. In vitro intrinsic dissolution into surfactant media were predicted using a model for surfactant-mediated dissolution. Compared to maleic buffer, POE and FeSSIF-V2 increased etravirine solubility 232-fold and 8.97-fold, respectively. From DLS, micelle diffusivity of drug-loaded POE micelle and FeSSIF-V2 mixed-micelle was 5.15x10^-7 cm²/s and 5.76x10^-8 cm²/s, respectively. Observed and predicted dissolution enhancement into POE were 50.7 and 31.3, and 1.26 and 1.24 into FeSSIF-V2, respectively. Hence, there was high dissolution enhancement into POE, although the observed enhancement was only 21.9% of the observed solubility enhancement, reflecting the attenuating impact of the large and slowly diffusing drug-loaded POE micelles. Meanwhile, there was minimal dissolution enhancement into FeSSIF-V2, and the observed enhancement was only 14.0% of the observed solubility enhancement, reflecting the even slower diffusing drug-loaded FeSSIF-V2 mixed-micelles compared to drug-loaded POE micelles. Results are considered in light of designing a single pharmaceutical surfactant system for dissolution that mimics a FeSSIF-V2 system.

Applications of bio-predictive dissolution tools for the development of solid oral dosage forms: Current industry experience

Development and optimization of orally administered drug products often require bio-predictive tools to help with informing formulation and manufacturing decisions. Reliable bio-predictive dissolution toolkits not only allow rational development of target formulations without having to conduct excessive in vivo studies but also help in detecting critical material attributes (CMAs), critical formulation variables (CFVs), or critical process parameters (CPPs) that could impact a drug's in vivo performance. To provide early insights for scientists on the development of a bio-predictive method for drug product development, this review summarizes current phase-appropriate bio-predictive dissolution approaches applicable to address typical concerns on solubility-limited absorption, food effect, achlorhydria, development of extended-release formulation, clinically relevant specification, and biowaiver. The selection of an in vitro method which can capture the key rate-limiting step(s) of the in vivo dissolution and/or absorption is considered to have a better chance to produce a meaningful in vitro-in vivo correlation (IVIVC) or in vitro-in vivo relationship (IVIVR).

An Open Label, Phase 1, Randomized, Seven-treatment, Seven-period, Crossover Study to Assess the Relative Bioavailability, pH Effect, Food Effect, and Dose Proportionality of CC-292, a Potent and Orally Available Bruton's Tyrosine Kinase Inhibitor

BACKGROUND AND OBJECTIVE

CC-292 is a potent, selective, orally administered small molecule inhibitor of Bruton's tyrosine kinase (BTK). To support the clinical investigation of CC-292, a randomized, seven-treatment, seven-period, crossover study was conducted to assess the relative bioavailability, pH effect, food effect, and dose-proportionality of two formulated tablets of CC-292.

METHODS

Healthy subjects (n = 24) were enrolled in the study and randomly assigned into different treatment sequences. Blood samples were collected at pre-specified time points to measure the drug concentrations in plasma. Statistical analyses were performed to compare the pharmacokinetics of CC-292 under different conditions.

RESULTS

The relative bioavailability of the newly developed formulation [spray-dried dispersion (SDD)] to the reference formulation (P22) was 1.24. When a single dose of CC-292 SDD tablet was administered under fed conditions, the area under the plasma concentration-time curve from time zero to infinity (AUC_∞) increased by 10.9% and the maximum plasma drug concentration C_max) decreased by 19.4% compared to when CC-292 was administered under fasted conditions. When a single dose of CC-292 SDD tablet was administered after multiple doses of omeprazole, the area under the plasma concentration-time curve from time zero to infinity (AUC_∞) decreased by 36.8% and the maximum plasma drug concentration C_max) decreased by 48.1% compared to when CC-292 was administered alone. Over a dose range of 100-300 mg (SDD formulation), CC-292 exhibited more than dose-proportional increases of drug exposures.

CONCLUSIONS

CC-292 was well tolerated when administered to healthy subjects as single oral doses under all conditions. Food intake had no clinically relevant impact on CC-292 pharmacokinetics compared to fasted conditions. Therefore, CC-292 can be administered with or without food. Co-administration of CC-292 with multiple doses of omeprazole (40 mg) decreased the pharmacokinetic exposure of CC-292. However, the effect was not clinically relevant.

CLINICAL TRIALS REGISTRATION

NCT02433457.

Reduced the Food Effect and Enhanced the Oral Bioavailability of Ivacaftor by Self-Nanoemulsifying Drug Delivery System (SNEDDS) Using a New Oil Phase

Purpose

The purpose of this work was to develop an ivacaftor self-nanoemulsion drug delivery system (IVA-SNEDDS) using the newly developed double headed miscellaneous lipid (DHML) as oil phase to reduce the food effect and inter-individual absorption variability of IVA.

Methods

The lipids with the greatest solubility to IVA were selected as the oil phase of IVA-SNEDDS by saturation solubility method. Then, among different surfactants and co-surfactants, those with good emulsifying ability for the selected oil phase were selected, and the proportion of surfactant and co-surfactant was further selected by pseudo-ternary phase diagram. The prepared IVA-SNEDDS were screened and evaluated in vitro and in beagle dogs.

Results

The optimized IVA-SNEDDS formulation consisting of DHML, Tween 80, and Transcutol HP with the weight ratio of 2:2:1 was physically stable and it was easy to disperse in water, pH 1.2 hydrochloric acid and pH 6.8 phosphate buffer solution, and generated a fine homogeneous nanoemulsion, with mean globule size less than 75 nm regardless of dilution ratio. In vitro drug release studies showed that the drug in IVA-SNEDDS could be completely released in a short time, while the drug release in IVA-suspension was less than 1% at 60 min. In vivo, using IVA-suspension (Fed) as a reference, the relative oral bioavailability of IVA-suspension (Fasted), IVA-SNEDDS (Fasted), and IVA-SNEDDS (Fed) were 23.35%, 153.63%, and 149.89%, respectively. This showed that IVA-SNEDDS could eliminate the positive food effect, improve the oral bioavailability, and reduce the IVA absorption difference between individuals.

Conclusion

As the oil phase of SNEDDS, DHML can significantly improve the drug solubility and drug loading of IVA-SNEDDS. Moreover, DHML was easily emulsified and can effectively form a nanoemulsion in vivo and in vitro. The prepared IVA-SNEDDS can reduce the inter-individual absorption variability of IVA, eliminate its food effect and improve its oral bioavailability.

Bio-enabling strategies to mitigate the pharmaceutical food effect: a mini review

The concomitant administration of oral drugs with food can result in significant changes in bioavailability, leading to variable pharmacokinetics and considerable clinical implications, such as over- or under-dosing. Consequently, there is increasing demand for bio-enabling formulation strategies to reduce variability in exposure between the fasted and fed state and/or mitigate the pharmaceutical food effect. The current review critically evaluates technologies that have been implemented to overcome the positive food effects of pharmaceutical drugs, including, lipid-based formulations, nanosized drug preparations, cyclodextrins, amorphisation and solid dispersions, prodrugs and salts. Additionally, improved insight into preclinical models for predicting the food effect is provided. Despite the wealth of research, this review demonstrates that application of optimal formulation strategies to mitigate the positive food effects and the evaluation in preclinical models is not a universal approach, and improved standardisation of models to predict the food effects would be desirable. Ultimately, the successful reformulation of specific drugs to eliminate the food effect provides a panoply of advantages for patients with regard to clinical efficacy and compliance.

Development of In Vitro Dissolution Testing Methods to Simulate Fed Conditions for Immediate Release Solid Oral Dosage Forms

In vitro dissolution testing is widely used to mimic and predict in vivo performance of oral drug products in the gastrointestinal (GI) tract. This literature review assesses the current in vitro dissolution methodologies being employed to simulate and predict in vivo drug dissolution under fasted and fed conditions, with emphasis on immediate release (IR) solid oral dosage forms. Notable human GI physiological conditions under fasted and fed states have been reviewed and summarized. Literature results showed that dissolution media, mechanical forces, and transit times are key dissolution test parameters for simulating specific postprandial conditions. A number of biorelevant systems, including the fed stomach model (FSM), GastroDuo device, dynamic gastric model (DGM), simulated gastrointestinal tract models (TIM), and the human gastric simulator (HGS), have been developed to mimic the postprandial state of the stomach. While these models have assisted in expanding physiological relevance of in vitro dissolution tests, in general, these models lack the ability to fully replicate physiological conditions/processes. Furthermore, the translatability of in vitro data to an in vivo system remains challenging. Additionally, physiologically based pharmacokinetic (PBPK) modeling has been employed to evaluate the effect of food on drug bioavailability and bioequivalence. Here, we assess the current status of in vitro dissolution methodologies and absorption PBPK modeling approaches to identify knowledge gaps and facilitate further development of in vitro dissolution methods that factor in fasted and fed states. Prediction of in vivo drug performance under fasted and fed conditions via in vitro dissolution testing and modeling may potentially help efforts in harmonizing global regulatory recommendations regarding in vivo fasted and fed bioequivalence studies for solid oral IR products.

Improving the dissolution behaviors and bioavailability of abiraterone acetate via multicomponent crystal forms

Abiraterone acetate (ABA), the first-line drug for the treatment of metastatic castration resistant prostate cancer (mCRPC), is administered at a high daily dosage of 1000 mg due to its poor solubility, and its fasted absolute oral bioavailability is estimated to be less than 10%. In this work we have focused on developing multicomponent forms with improved dissolution behaviors and bioavailability. Two salts of ABA with malonic acid (ABA-MA) and saccharin (ABA-SAC), and five cocrystals with trans-aconitic acid (ABA-TAA), 1-hydroxy-2-naphthoic acid (ABA-1HNA), pyrocatechol (ABA-PCA), resorcinol (ABA-RES) and hydroquinone (ABA-HDE) were successfully obtained. Their crystal structures were elucidated by single crystal X-ray diffraction, and these multicomponent forms were fully characterized by powder X-ray diffraction, thermal analysis and Fourier Transform Infrared spectra. Among them, ABA-TAA cocrystal shows substantial enhancements both in the solubility and intrinsic dissolution rates in different buffer solutions. In the meantime, we unexpectedly found the gelation of ABA-MA salt and ABA-SAC salt in pH 2.0 buffer solution. The gel-like materials generated on the surface of drug will suppress the release of ABA. Moreover, in vivo pharmacokinetic study on beagle dogs was conducted for ABA-TAA cocrystal preparation and ABA commercial product, and ABA-TAA cocrystal preparation shows enhanced absorption. These advantages in dissolution behaviors and bioavailability demonstrate the potential of ABA-TAA cocrystal to be a better candidate for the treatment of mCRPC compared with ABA.

Relative Bioavailability and Food Effect of GSK3640254 Tablet and Capsule Formulations in Healthy Participants

GSK3640254 is a next‐generation maturation inhibitor with demonstrated potency across HIV‐1 subtypes and a high barrier to emergent resistance. This phase I, 2‐part, randomized, open‐label study (ClinicalTrials.gov identifier, NCT04263142) in healthy participants assessed the relative bioavailability of a single dose of GSK3640254 200 mg in tablet and capsule formulations (part 1) and the effect of food on the pharmacokinetic profile of the tablet formulation (part 2). Overall, 39 participants were randomized to treatment (part 1, n = 18; part 2, n = 21). All participants in part 1 completed the study; 2 participants in part 2 withdrew before study completion (adverse event, n = 1; physician decision, n = 1). In part 1, plasma exposures of the GSK3640254 tablet formulation were not meaningfully different from those of the capsule formulation when administered in the presence of a moderate‐fat meal. In part 2, GSK3640254 plasma exposures increased by ≈3‐ to 4‐fold under high‐ and moderate‐fat conditions, respectively, compared with fasted conditions. No major safety or tolerability findings were observed. The highest incidence of adverse events (24%) was reported under high‐fat conditions. Taken together, these data support the use of the tablet formulation coadministered with food in the clinical development of GSK3640254 for treatment of HIV‐1.

Machine learning predicts the effect of food on orally administered medicines

Food-mediated changes to drug absorption, termed the food effect, are hard to predict and can have significant implications for the safety and efficacy of oral drug products in patients. Mimicking the prandial states of the human gastrointestinal tract in preclinical studies is challenging, poorly predictive and can produce difficult to interpret datasets. Machine learning (ML) has emerged from the computer science field and shows promise in interpreting complex datasets present in the pharmaceutical field. A ML-based approach aimed to predict the food effect based on an extensive dataset of over 311 drugs with more than 20 drug physicochemical properties, referred to as features. Machine learning techniques were tested; including logistic regression, support vector machine, k-Nearest neighbours and random forest. First a standard ML pipeline using a 80:20 split for training and testing was tried to predict no food effect, negative food effect and positive food effect, however this lead to specificities of less than 40%. To overcome this, a strategic ML pipeline was devised and three tasks were developed. Random forest achieved the strongest performance overall. High accuracies and sensitivities of 70%, 80% and 70% and specificities of 71%, 76% and 71% were achieved for classifying; (i) no food effect vs food effect, (ii) negative food vs positive food effect and (iii) no food effect vs negative food effect vs positive food effect, respectively. Feature importance using random forest ranked the features by importance for building the predictive tasks. The calculated dose number was the most important feature. Here, ML has provided an effective screening tool for predicting the food effect, with the potential to select lead compounds with no food effect, reduce the number of animal studies, and accelerate oral drug development studies.

Exploring the Relationship of Drug BCS Classification, Food Effect, and Gastric pH-Dependent Drug Interactions

Food effect (FE) and gastric pH-dependent drug-drug interactions (DDIs) are both absorption-related. Here, we evaluated if Biopharmaceutics Classification System (BCS) classes may be correlated with FE or pH-dependent DDIs. Trends in FE data were investigated for 170 drugs with clinical FE studies from the literature and new drugs approved from 2013 to 2019 by US Food and Drug Administration. A subset of 38 drugs was also evaluated to determine whether FE results can inform the need for a gastric pH-dependent DDI study. The results of FE studies were defined as no effect (AUC ratio 0.80-1.25), increased exposure (AUC ratio ≥1.25), or decreased exposure (AUC ratio ≤0.8). Drugs with significantly increased exposure FE (AUC ratio ≥2.0; N=14) were BCS Class 2 or 4, while drugs with significantly decreased exposure FE (AUC ratio ≤0.5; N=2) were BCS Class 1/3 or 3. The lack of FE was aligned with the lack of a pH-dependent DDI for all 7 BCS Class 1 or 3 drugs as expected. For the 13 BCS Class 2 or 4 weak base drugs with an increased exposure FE, 6 had a pH-dependent DDI (AUC ratio ≤0.8). Among the 16 BCS Class 2 or 4 weak base drugs with no FE, 6 had a pH-dependent DDI (AUC ratio ≤0.8). FE appears to have limited correlation with BCS classes except for BCS Class 1 drugs, confirming that multiple physiological mechanisms can impact FE. Lack of FE does not indicate absence of pH-dependent DDI for BCS Class 2 or 4 drugs. Graphical Abstract.

Best practices in current models mimicking drug permeability in the gastrointestinal tract - an UNGAP review

The absorption of orally administered drug products is a complex, dynamic process, dependent on a range of biopharmaceutical properties; notably the aqueous solubility of a molecule, stability within the gastrointestinal tract (GIT) and permeability. From a regulatory perspective, the concept of high intestinal permeability is intrinsically linked to the fraction of the oral dose absorbed. The relationship between permeability and the extent of absorption means that experimental models of permeability have regularly been used as a surrogate measure to estimate the fraction absorbed. Accurate assessment of a molecule's intestinal permeability is of critical importance during the pharmaceutical development process of oral drug products, and the current review provides a critique of in vivo, in vitro and ex vivo approaches. The usefulness of in silico models to predict drug permeability is also discussed and an overview of solvent systems used in permeability assessments is provided. Studies of drug absorption in humans are an indirect indicator of intestinal permeability, but in vitro and ex vivo tools provide initial screening approaches are important tools for direct assessment of permeability in drug development. Continued refinement of the accuracy of in silico approaches and their validation with human in vivo data will facilitate more efficient characterisation of permeability earlier in the drug development process and will provide useful inputs for integrated, end-to-end absorption modelling.

Comparison of Predictions by BCS, rDCS and Machine Learning for the Effect of Food on Oral Drug Absorption Based on Features Calculated In silico

In this study, observed food effects of 473 drugs were categorized into positive, negative, or no effects and compared with the predictions made by machine learning (ML), the Biopharmaceutics Classification System (BCS) and refined Developability Classification System (rDCS). All methods used primarily in silico estimates for prediction, and for ML, four algorithms were evaluated using nested cross-validation to select important information from 371 features calculated based on the chemical structure. Approximately 18 features, including estimated solubility in biorelevant media, were selected as important, and the random forest classifier was the best among four algorithms with 36.6% error rate (ER) and 10.8% opposite prediction rate (OPR). The prediction by rDCS utilizing solubility in a biorelevant medium was somewhat inferior, but not by much; 41.0% ER and 11.4% OPR. Compared with these two methods, the prediction by BCS was inferior; 54.5% ER and 21.4% OPR. ER was improved modestly by using measured features instead of in silico estimates when BCS was applied to a subset of 151 drugs (46.4% from 55.0%). ML and rDCS predicted the food effects of the same subset using in silico estimates with ERs of 37.7% and 42.4%, respectively, suggesting that the predictions by ML and rDCS using in silico features are similar or more accurate than those by BCS using measured features. These results suggest that ML was useful in revealing essential features from complex information and, together with rDCS, is effective in predicting food effects during drug development, including early drug discovery.

Bioequivalence Study of Palbociclib Capsules in Healthy Chinese Subjects Under Fasting and Fed Conditions

BACKGROUND AND OBJECTIVE

Palbociclib is an oral small-molecule inhibitor of cyclin-dependent kinase 4/6 used for the treatment of advanced breast cancer. This study compared the pharmacokinetic and safety profiles between a new generic and a branded reference formulation of palbociclib capsules in healthy Chinese subjects under fasting and fed conditions and evaluated the bioequivalence of two palbociclib products to obtain sufficient evidence for the marketing approval of the new generic drug.

METHODS

A randomized, open-label, two-period crossover study was conducted in healthy Chinese volunteers under both fasting and fed conditions (30 subjects/condition). Eligible healthy subjects received a single 125-mg dose of the palbociclib test or reference formulation followed by a 14-day washout period. Serial blood samples were collected at scheduled timepoints, and plasma concentrations were determined by a validated high-performance liquid chromatography-tandem mass spectrometry method. A non-compartment method was used to calculate the main pharmacokinetic parameters, including the area under the plasma concentration-time curve (AUC) from time 0 to the time of the last measurable concentration (AUC_0-t), the AUC from time 0 to infinity (AUC_0-∞), the maximum plasma concentration (C_max), the time to maximum plasma concentration, and the elimination half-life. The geometric mean ratios and the corresponding 90% confidence intervals of palbociclib were acquired for the bioequivalence analysis. Safety and tolerability were assessed by monitoring adverse events, laboratory assessments, vital signs, physical examinations, and 12-lead electrocardiograms.

RESULTS

Under the fasting condition, the pharmacokinetic parameter values of the test formulation were similar to those of the reference formulation. The 90% confidence intervals of geometric mean ratios of the test to reference formulations were 94.35-103.82% for C_max, 94.79-103.26% for AUC_0-t, and 94.82-103.38% for AUC_0-∞, which are all within the accepted bioequivalence range of 80.00-125.00%. Meanwhile, under the fed condition, the pharmacokinetic parameter values of the test formulation were also similar to those of the reference formulation. The 90% confidence intervals of geometric mean ratios of the test to reference formulations were 96.65-103.56% for C_max, 98.06-103.61% for AUC_0-t, and 97.88-103.46% for AUC_0-∞, which are all within the accepted bioequivalence range of 80.00-125.00%. The test and reference products were well tolerated, and no serious adverse events occurred during the study.

CONCLUSIONS

Pharmacokinetic bioequivalence of palbociclib in healthy subjects was established between the palbociclib test formulation and the reference formulation under fasting and fed conditions according to predetermined regulatory criteria. The two formulations were safe and well tolerated.

A Non-Nutritive Feeding Intervention Alters the Expression of Efflux Transporters in the Gastrointestinal Tract

Intestinal interactions with nutrients, xenobiotics and endogenous hormones can influence the expression of clinically relevant membrane transporters. These changes in the gastrointestinal (GI) physiology can in turn affect the absorption of numerous drug substrates. Several studies have examined the effect of food on intestinal transporters in male and female humans and animal models. However, to our knowledge no studies have investigated the influence of a non-nutritive fibre meal on intestinal efflux transporters and key sex and GI hormones. Here, we show that a fibre meal increased the acute expression of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug-resistance-associated protein-2 (MRP2) in small intestinal segments in both male and female Wistar rats. Enzyme-linked immunosorbent assays were used for the protein quantification of efflux transporters and hormonal plasma concentration. In male rats, the fibre meal caused the plasma concentration of the GI hormone cholecystokinin (CCK) to increase by 75% and the sex hormone testosterone to decrease by 50%, whereas, in contrast, the housing food meal caused a decrease in CCK by 32% and testosterone saw an increase of 31%. No significant changes in the hormonal concentrations, however, were seen in female rats. A deeper understanding of the modulation of efflux transporters by sex, food intake and time can improve our understanding of inter- and intra-variability in the pharmacokinetics of drug substrates.

Machine learning methods for prediction of food effects on bioavailability: A comparison of support vector machines and artificial neural networks

Despite countless advances in recent decades across various in vitro, in vivo and in silico tools, anticipation of whether a drug will show a human food effect (FE) remains challenging. One means to predict potential FE involves probing any dependence between FE and drug properties. Accordingly, this study explored the potential for two machine learning (ML) algorithms to predict likely FE. Using a collated database of drugs licensed from 2016-2020, drugs were classified into three groups; positive, negative or no FE. Greater than 250 drug properties were predicted for each drug which were used to train predictive models using Support Vector Machine (SVM) and Artificial Neural Network (ANN) algorithms. When compared, ANN outperformed SVM for FE classification upon training (82%, 72%) and testing (72%, 69%). Both models demonstrated higher FE prediction accuracy than the Biopharmaceutics Classification System (BCS) (46%). This exploratory work provided new insights into the connection between FE and drug properties as the Octanol Water Partition Coefficient (S+logP), Number of Hydrogen Bond Donors (HBD), Topological Polar Surface Area (T_PSA) and Dose (mg) were all significant for prediction. Overall, this study demonstrated the utility of ML to facilitate early anticipation of likely FE in pre-clinical development using four well-known drug properties.

Lipophilic Salts and Lipid-Based Formulations for Bridging the Food Effect Gap of Venetoclax

Lipid based formulations (LBF) have shown to overcome food dependent bioavailability for some poorly water-soluble drugs. However, the utility of LBFs can be limited by low dose loading due to a low drug solubility in LBF vehicles. This study investigated the solubility and drug loading increases in LBFs using lipophilic counterions to form lipophilic salts of venetoclax. Venetoclax docusate was formed from venetoclax free base and verified by ¹H NMR. Formation of stable venetoclax-fatty acid associations with either oleic acid or decanoic acid were attempted, however, the molecular associations were less consistent based on ¹H NMR. Venetoclax docusate displayed a up to 6.2-fold higher solubility in self-emulsifying drug delivery systems (SEDDS) when compared to the venetoclax free base solubility resulting in a higher dose loading. A subsequent bioavailability study in landrace pigs demonstrated a 2.5-fold higher bioavailability for the lipophilic salt containing long chain SEDDS compared to the commercially available solid dispersion Venclyxto® in the fasted state. The bioavailability of all lipophilic salt SEDDS in the fasted state was similar to Venclyxto® in the fed state. This study confirmed that lipophilic drug salts increase the dose loading in LBFs and showed that lipophilic salt-SEDDS combinations may be able to overcome bioavailability limitations of drugs with low inherent dose loading in lipid vehicles. Furthermore, the present study demonstrated the utility of a LBF approach, in combination with lipophilic salts, to overcome food dependent variable oral bioavailability of drugs.

Investigation of Self-Emulsifying Drug-Delivery System Interaction with a Biomimetic Membrane under Conditions Relevant to the Small Intestine

Self-emulsifying drug-delivery systems (SEDDS) have been extensively shown to increase oral absorption of solvation-limited compounds. However, there has been little clinical and commercial use of these formulations, in large part because the demonstrated advantages of SEDDS have been outweighed by our inability to precisely predict drug absorption from SEDDS using current in vitro assays. To overcome this limitation and increase the biological relevancy of in vitro assays, an absorption function can be incorporated using biomimetic membranes. However, the effects that SEDDS have on the integrity of a biomimetic membrane are not known. In this study, a quartz crystal microbalance with dissipation monitoring and total internal reflection fluorescence microscopy were employed as complementary methods to in vitro lipolysis-permeation assays to characterize the interaction of various actively digested SEDDS with a liquescent artificial membrane comprising lecithin in dodecane (LiDo). Observations from surface analysis showed that interactions between the digesting SEDDS and LiDo membrane coincided with inflection points in the digestion profiles. Importantly, no indications of membrane damage could be observed, which was supported by flux profiles of the lipophilic model drug felodipine (FEL) and impermeable marker Lucifer yellow on the basal side of the membrane. There was a correlation between the digestion kinetics of the SEDDS and the flux of FEL, but no clear correlation between solubilization and absorption profiles. Membrane interactions were dependent on the composition of lipids within each SEDDS, with the more digestible lipids leading to more pronounced interactions, but in all cases, the integrity of the membrane was maintained. These insights demonstrate that LiDo membranes are compatible with in vitro lipolysis assays for improving predictions of drug absorption from lipid-based formulations.

Nanoparticulate Drug Delivery Strategies to Address Intestinal Cytochrome P450 CYP3A4 Metabolism towards Personalized Medicine

Drug dosing in clinical practice, which determines optimal efficacy, toxicity or ineffectiveness, is critical to patients' outcomes. However, many orally administered therapeutic drugs are susceptible to biotransformation by a group of important oxidative enzymes, known as cytochrome P450s (CYPs). In particular, CYP3A4 is a low specificity isoenzyme of the CYPs family, which contributes to the metabolism of approximately 50% of all marketed drugs. Induction or inhibition of CYP3A4 activity results in the varied oral bioavailability and unwanted drug-drug, drug-food, and drug-herb interactions. This review explores the need for addressing intestinal CYP3A4 metabolism and investigates the opportunities to incorporate lipid-based oral drug delivery to enable precise dosing. A variety of lipid- and lipid-polymer hybrid-nanoparticles are highlighted to improve drug bioavailability. These drug carriers are designed to target different intestinal regions, including (1) local saturation or inhibition of CYP3A4 activity at duodenum and proximal jejunum; (2) CYP3A4 bypass via lymphatic absorption; (3) pH-responsive drug release or vitamin-B12 targeted cellular uptake in the distal intestine. Exploitation of lipidic nanosystems not only revives drugs removed from clinical practice due to serious drug-drug interactions, but also provide alternative approaches to reduce pharmacokinetic variability.

Overcoming the Low Oral Bioavailability of Deuterated Pyrazoloquinolinone Ligand DK-I-60-3 by Nanonization: A Knowledge-Based Approach

Poor water solubility of new chemical entities is considered as one of the main obstacles in drug development, as it usually leads to low bioavailability after administration. To overcome these problems, the selection of the appropriate formulation technology needs to be based on the physicochemical properties of the drug and introduced in the early stages of drug research. One example of the new potential drug substance with poor solubility is DK-I-60-3, deuterated pyrazoloquinolinone, designed for the treatment of various neuropsychiatric disorders. In this research, based on preformulation studies, nanocrystal technology was chosen to improve the oral bioavailability of DK-I-60-3. Nanocrystal dispersions stabilized by sodium lauryl sulfate and polyvinylpyrrolidone were prepared by modified wet media milling technique, with the selection of appropriate process and formulation parameters. The nanoparticles characterization included particle size and zeta potential measurements, differential scanning calorimetry, X-ray powder diffraction, dissolution and solubility study, and in vivo pharmacokinetic experiments. Developed formulations had small uniform particle sizes and were stable for three months. Nanonization caused decreased crystallite size and induced crystal defects formation, as well as a DK-I-60-3 solubility increase. Furthermore, after oral administration of the developed formulations in rats, two to three-fold bioavailability enhancement was observed in plasma and investigated organs, including the brain.

The Impact of Diet and Exercise on Drug Responses

It is well known that lifestyle changes can alter several physiological functions in the human body. For exercise and diet, these effects are used sensibly in basic therapies, as in cardiovascular diseases. However, the physiological changes induced by exercise and a modified diet also have the capacity to influence the efficacy and toxicity of several drugs, mainly by affecting different pharmacokinetic mechanisms. This pharmacological plasticity is not clinically relevant in all cases but might play an important role in altering the effects of very common drugs, particularly drugs with a narrow therapeutic window. Therefore, with this review, we provide insights into possible food–drug and exercise–drug interactions to sharpen awareness of the potential occurrence of such effects.

Clinical investigation of the biopharmaceutical characteristics of nifurtimox tablets - Implications for quality control and application

Nifurtimox is approved in Chagas disease and has been used in endemic countries since the 1960s. Nifurtimox, available as a 120 mg tablet, is administered with food typically three times daily, and dose is adjusted for age and bodyweight. Accurately or reproducibly fragmenting the 120 mg tablet for dose adjustment in young children and those with low bodyweight is problematic. Based on the existing tablet formulation, new nifurtimox 30 mg and 120 mg tablets have been developed in a format that can be divided accurately into 15 mg and 60 mg fragments. In adults with chronic Chagas disease, we investigated whether nifurtimox bioavailability is affected by tablet dissolution rate, and whether different diets affect nifurtimox bioavailability. In an open-label, three-period cross-over study (n=36; ClinicalTrials.gov, NCT03350295), patients randomly received three 30 mg tablet formulations (slow, medium, or fast dissolution; a 4 × 30 mg dose of one formulation per period). In an open-label, four-period cross-over study (n=24; ClinicalTrials.gov, NCT03334838) patients randomly fasted or received one of three meal types (high-fat/high-calorie, low-fat, dairy-based) before ingesting nifurtimox (a 4 × 30 mg dose per period). Acceptance criteria for no difference between groups were 90% confidence intervals (CIs) of exposure ratios in the range 0.8-1.25. Nifurtimox bioavailability was unaffected by tablet dissolution kinetics. Ratios of area under the curve at final assessment (AUC_(0-tlast) [90% CI]) were: fast/medium dissolution, 1.061 (0.990-1.137); slow/medium dissolution, 0.964 (0.900-1.033); fast/slow dissolution, 1.100 (1.027-1.179). Compared with a fasting state, nifurtimox bioavailability increased by 73% after a high-fat/high-calorie meal (AUC_(0-tlast) ratio [90% CI], 1.732 [1.581-1.898]); smaller increases were seen with the other meal types (low-fat: 1.602 [1.462-1.755]; dairy-based: 1.340 [1.222-1.468]). Although type of diet can affect bioavailability, taking nifurtimox with food is most important.