Relative Oral Bioavailability and Food Effects of Two Sepiapterin Formulations in Healthy Participants

Sepiapterin is an orally administered drug in development for the treatment of phenylketonuria, an inborn error of metabolism characterized by the deficiency of the phenylalanine-metabolizing enzyme phenylalanine hydroxylase. This study characterized the pharmacokinetics, safety, and tolerability of 2 clinical sepiapterin formulations (Phase 1/2, Phase 3) and the effects of food on the pharmacokinetics of the Phase 3 formulation in healthy participants. In Part A, 18 participants were randomized to one of 2 treatment sequences, each with 4 dosing periods comprising a single dose (20 or 60 mg/kg) of the Phase 1/2 or the Phase 3 formulation with a low-fat diet. In Part B, 14 participants were randomized to one of 2 sequences, each comprising 4 dosing periods of a single dose (20 or 60 mg/kg) of the Phase 3 formulation under fed (high-fat) or fasted conditions. Following oral administration, sepiapterin was quickly absorbed and rapidly and extensively converted to tetrahydrobiopterin (BH4). BH4 was the major circulating active moiety. Under low-fat conditions, the Phase 3 formulation was bioequivalent to the Phase 1/2 formulation at 20 mg/kg, while slightly lower BH4 exposure (approximately 0.81×) for the Phase 3 formulation was observed at 60 mg/kg. BH4 exposure increased to approximately 1.7× under the low-fat condition and approximately 2.8× under the high-fat condition at a dose of either 20 or 60 mg/kg for the Phase 3 formulation, compared with the fasted condition. Both sepiapterin formulations were well tolerated, with no serious or severe adverse events reported. All treatment-emergent adverse events were mild or moderate in severity.

Safety, tolerability, and pharmacokinetics of the novel RdRp inhibitor SHEN26 against SARS-CoV-2: a randomized, placebo-controlled, double-blind Phase I study in healthy subjects

BACKGROUND

SHEN26, an oral broad-spectrum antiviral drug, possesses potent preclinical activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has a favorable safety profile.

METHODS

We report safety, tolerability, and pharmacokinetic data from a randomized, double-blind, placebo-controlled phase I study of SHEN26. Eighty-six healthy subjects were enrolled in the three studies: a single ascending-dose study (SAD), a multiple ascending-dose study (MAD), and a food-effect study (FE).

RESULTS

In the SAD trial, the maximum observed plasma concentration (Cmax) and area under the curve (AUC) of the SHEN26 rapid metabolite SHEN26-69-0 increased approximately dose-proportionally in the 50-400 mg fasting dose range. In the 800 mg dose group, standard meals increased the Cmax and AUC of SHEN26-69-0. In the MAD trial, the accumulation ratios of Cmax and AUC indicated slight accumulation upon repeated SHEN26 dosing. In the FE trial, a high-fat meal prolonged the time to maximum plasma concentration (Tmax) and increased the Cmax and AUC of SHEN26-69-0 compared with fasting administration. Most treatment-related adverse events were mild and resolved without treatment.

CONCLUSION

SHEN26 demonstrated satisfactory safety and tolerability in healthy subjects, which supports the continued study of SHEN26 against SARS-CoV-2.

TRIAL REGISTRATION

The trial is registered in ClinicalTrials.gov (CT. gov identifier: NCT05504746).

Pharmacokinetics of Nitazoxanide Dry Suspensions After Single Oral Doses in Healthy Subjects: Food Effects Evaluation and Bioequivalence Study

Nitazoxanide (NTZ) is an effective antiparasitic drug with potent antiviral and antimicrobial activity. This randomized, open-label, 2-sequence, 2-period crossover trial was designed to evaluate the bioequivalence (BE) of the NTZ dry suspension in healthy subjects and investigated the effect of food intake on the pharmacokinetic (PK) properties of tizoxanide (an active metabolite of NTZ, TIZ). Sixty healthy Chinese subjects were enrolled and received a single dose of 500 mg/25 mL of preparations on days 1 and 4 under overnight fasting or fed conditions, respectively. The plasma concentration of TIZ was determined using high-performance liquid chromatography/tandem mass spectrometry. PK parameters were calculated using WinNonlin 8.2 and BE was evaluated using SAS 9.4. The 90% confidence intervals for the geometric mean ratio (test/reference) of maximum concentration (Cmax), the area under the curve from time 0 to the time of the last quantifiable concentration (AUC0-t), and the area under the curve from time 0 to extrapolation to infinity (AUC0-∞) were all within the equivalent interval of 80%-125%, compliant with BE requirements. In comparison with fasting, on taking the reference and test preparations of the NTZ dry suspension after a meal, the AUC0-t increased by 48.9% and 47.3%, respectively, the AUC0-∞ increased by 48.4% and 48.3%, respectively, and the post-meal Tmax was prolonged by 1.8-2 hours. Our results demonstrate that the test and reference preparations were bioequivalent. High-fat meals significantly improve the degree of drug absorption and delay the rate of drug absorption.

Food-Drug Effects and Pediatric Drug Development Studies Submitted to the US Food and Drug Administration, 2012-2022

Food effect (FE) studies characterize food-drug interactions that may alter the efficacy or safety of a drug, but these studies are not conducted in pediatric patients. Pediatric patients have substantial physiologic, anatomic, and dietary differences from adults, which may result in differences in their FE considerations. Therefore, the objective of this study was to identify oral drug products approved for use in pediatric patients aged <6 years with an FE observed in adults. Additional objectives were to summarize the therapeutic areas, pharmacokinetic effects, and labeling instructions that resulted from these studies. Publicly available data were searched for products studied in pediatric patients and approved for use by the United States Food and Drug Administration (FDA) from 2012 to 2022. Of the 102 oral drug products approved for use in patients aged <6 years, 43 recommended the consideration of food intake in the drug labeling. These included drug products recommended to be taken with food (n = 21, 49%) or without food (n = 14, 33%). Each of the 14 drug products recommended to be taken without food are approved for use in pediatric patients aged <2 years. The products approved for use in pediatric patients aged <2 years comprised the highest proportion with area under the plasma concentration-time curve extrapolated to infinity (AUCinf , n = 35, 75%) and maximum serum concentration (Cmax , n = 45, 80%) affected by food. Close monitoring is warranted during the postapproval period for products identified as having a significant FE in adults and that are approved for use in pediatric patients aged <6 years. Promising tools for predicting pediatric FE may include physiologically based pharmacokinetic absorption modeling.

Pharmacokinetics of Nifedipine-Sustained Release Tablets in Healthy Subjects After a Single Oral Administration: Bioequivalence Analysis and Food Effects

We compared newly developed delayed-release oral tablets (test) of 30-mg nifedipine (NFP) with its marketed counterpart (30 mg; reference) in healthy adult Chinese volunteers to assess the former's bioequivalence. This was a randomized, open-label, four-period, crossover trial study including fasting and fed trials. The participants were randomly administered test or reference formulations (1:1 ratio) throughout each period, with a 7-day washout period. In the next session, they were administered the alternate products. Liquid chromatography-tandem mass spectrometry and WinNonlin software were used to evaluate the bioequivalence of the maximum plasma concentration (Cmax ) of NFP and the area under the concentration-time curve (AUC). In total, 46 and 48 people participated in the fasting and postprandial trials. In both groups, the 90% confidence intervals of geometric mean ratios of Cmax , AUC from time zero to time t, and AUC from time zero to infinity were in the equivalence range (80%-125%). When NFP was administered concomitantly with a high-fat meal, time to maximum concentration was approximately twofold earlier, absorption was approximately 4.8% less, and Cmax exhibited a slight change relative to those under fasting conditions. Moreover, no serious adverse events were recorded in the participants. The present findings confirm the bioequivalence of test and reference formulations of NFP tablets under fasting and postprandial conditions.

Pharmacokinetics of Esomeprazole Magnesium After Single Oral Doses in Healthy Subjects: Bioequivalence Study and Food Effects

This study was designed to evaluate the bioequivalence of the newly developed delayed-release oral suspension (test) 40 mg esomeprazole magnesium compared to its marketed counterpart (40 mg; reference) in healthy adult Chinese subjects. We conducted randomized, open-label, two-period, single-dose, two-way crossover trials over a 7-day washout period, comprising a fasting trial and a fed trial. The subjects were administered the test or reference products in a 1:1 ratio at random throughout each period. Then, in the next session, they received the alternate products. Liquid chromatography-tandem mass spectrometry and WinNonlin software were used to assess the bioequivalence of esomeprazole peak plasma concentration (C_max ) and area under the concentration-time curve (AUC). Overall, 33 subjects participated in the fasting trial and 42 subjects participated in the fed trial. Under both situations, the 90% confidence interval for the ratio of geometric means of C_max , AUC_0-t , and AUC_0-∞ were within equivalence ranges (80%-125%). In these trials, no severe adverse events or protocol violations were observed. Moreover, when esomeprazole was administered while fed, the t_max was delayed, and both C_max and AUC were reduced. The results of this research suggest that the test and reference formulations were bioequivalent under fasting and fed states.

Safety, Tolerability, and Pharmacokinetics of Single and Multiple Ascending Oral Doses of Youkenafil Hydrochloride, a Phosphodiesterase Type 5 Inhibitor, in Healthy Chinese Male Volunteers

Youkenafil hydrochloride is a novel selective phosphodiesterase type 5 inhibitor for the treatment of erectile dysfunction. Its safety, tolerability, and pharmacokinetics were evaluated in healthy Chinese male volunteers. In addition, this study explored the effect of food on the pharmacokinetic parameters of youkenafil hydrochloride. The study was divided into 3 trials: a single ascending dose (25, 50, 100, 150, or 200 mg youkenafil), multiple dose (50, 100, or 150 mg youkenafil once daily for 7 consecutive days), and food effect (50 mg youkenafil single dose). The overall tolerability of youkenafil was good. Youkenafil was rapidly absorbed after a single oral dose. Food intake impeded absorption efficiency but had no significant effect on area under the plasma concentration-time curve values. The mean accumulation ratio in area under the plasma concentration-time curve and maximum plasma concentration ranged from 1.3 to 1.6 and from 1.2 to 1.4 after once-daily dosing. There was no apparent accumulation following consecutive administration for 7 days. Less than 1% of the dose was found in urine as the intact drug for all dose groups. Single-dose youkenafil up to 200 mg and multiple doses up to 150 mg were generally safe and well tolerated.

Does Food Affect the Pharmacokinetics of Non-orally Delivered Drugs? A Review of Currently Available Evidence

The food effects for orally administered drugs have been widely investigated and reviewed. In contrast, our knowledge of food effects for non-orally administered drugs is scarce. In this review paper, we did a literature survey to collect clinical food effect data for non-orally administered drugs. Our survey retrieved 18 drugs, including thirteen intravenously (IV), two subcutaneously (SC), one intradermally (ID), one pulmonary, and one rectally administered drug. The food effect data show that food intake can increase the absorption of SC and ID administered peptides and proteins with MW < 30 kDa by 30-50%. On the other hand, food intake can increase the elimination of IV and inhaled drugs with moderate and high hepatic extraction and reduce drug exposure by up to 35%. The food effect knowledge can be used to mitigate potential efficacy and safety risks of non-orally administered drugs.

Practical and operational considerations related to paediatric oral drug formulation: an industry survey

For over 15 years, US and EU regulations ensure that medicines developed for children are explicitly authorised for such use with age-appropriate forms and formulations, implying dedicated research. To shed light on how these regulations have been adopted by pharmaceutical companies and how various aspects of paediatric oral drug formulation development are currently handled, an exploratory survey was conducted. Topics included: general company policy, regulatory aspects, dosage form selection, in-vitro, in-silico and (non-)clinical in-vivo methods, and food effects assessment. The survey results clearly underline the positive impact of the paediatric regulations and their overall uptake across the pharmaceutical industry. Even though significant improvements have been made in paediatric product development, major challenges remain. In this respect, dosage form selection faces a discrepancy between the youngest age groups (liquid products preference) and older subpopulations (adult formulation preference). Additionally, concerted research is needed in the development and validation of in-vitro tools and physiology based pharmacokinetic models tailored to the paediatric population, and in estimating the effect of non-standard and paediatric relevant foods. The current momentum in paediatric drug development and research should allow for an evolution in standardised methodology and guidance to develop paediatric formulations, which would benefit pharmaceutical industry and regulators.

State of the Art and Uses for the Biopharmaceutics Drug Disposition Classification System (BDDCS): New Additions, Revisions, and Citation References

The Biopharmaceutics Drug Disposition Classification system (BDDCS) is a four-class approach based on water solubility and extent of metabolism/permeability rate. Based on the BDDCS class to which a drug is assigned, it is possible to predict the role of metabolic enzymes and transporters on the drug disposition of a new molecular entity (NME) prior to its administration to animals or humans. Here, we report a total of 1475 drugs and active metabolites to which the BDDCS is applied. Of these, 379 are new entries, and 1096 are revisions of former classification studies with the addition of references for the approved maximum dose strength, extent of the systemically available drug excreted unchanged in the urine, and lowest solubility over the pH range 1.0–6.8 when such information is available in the literature. We detail revised class assignments of previously misclassified drugs and the literature analyses to classify new drugs. We review the process of solubility assessment for NMEs prior to drug dosing in humans and approved dose classification, as well as the comparison of Biopharmaceutics Classification System (BCS) versus BDDCS assignment. We detail the uses of BDDCS in predicting, prior to dosing animals or humans, disposition characteristics, potential brain penetration, food effect, and drug-induced liver injury (DILI) potential. This work provides an update on the current status of the BDDCS and its uses in the drug development process.

Pharmacokinetics of Flunarizine Hydrochloride After Single Oral Doses in Healthy Subjects: Bioequivalence Study and Food Effects

We designed a study to compare the newly developed 5-mg flunarizine hydrochloride capsules (test) to that of its marketed counterpart (5-mg; reference) among healthy adult Chinese volunteers. We performed an open-label, single-center study that consisted of 2 randomized, crossover trials, including a fasting trial and a fed trial. In each part of the study, the subjects were randomly assigned to either receive the test or reference products (5-mg flunarizine) in a 1:1 ratio. Subjects then received the alternative products, following a 14-day washout period. Concentrations of plasma flunarizine were analyzed using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters (noncompartmental model) were evaluated using the WinNonlin software. The analysis of variance and Food and Drug Administration bioequivalence statistical criterion of 90% confidence interval for 80% to 125% range (set at P ≤ .05) of geometric means ratios of test: reference product for peak plasma concentration, area under the plasma concentration-time curve (AUC) from time 0 to time t, and AUC from time 0 to infinity were determined. Tolerability was evaluated during the entire study period. Overall, 23 volunteers completed the fasting study, while 40 volunteers completed the fed study. The test formulation was found to be bioequivalent to the marketed formulation, as the 90% confidence interval for the ratio of geometric means of peak plasma concentration (fasting: 87.61%-101.67%; fed: 87.38%-104.06%), AUC from time 0 to time t (fasting: 89.44%-99.92%; fed: 92.65%-98.28%), and AUC from time 0 to infinity (fasting: 95.02%-104.33%; fed: 90.41%-96.96%) were within equivalence limits (80-125%) under both the fasting and fed conditions. When flunarizine was given alongside high-fat meals, time to maximum concentration was delayed ≈3.5 hours compared to fasting conditions. Meantime, high-fat meals increased its exposure by nearly 50%. Furthermore, there were no serious adverse events found among the subjects. This study confirmed that test and reference flunarizine hydrochloride capsules were bioequivalent under fasting and postprandial conditions.

Effects of Food on the Pharmacokinetic Properties and Mass Balance of Henagliflozin in Healthy Male Volunteers

PURPOSE

Henagliflozin is a highly selective and effective sodium glucose co-transporter (SGLT)-2 inhibitor developed for the treatment of patients with type 2 diabetes mellitus (T2DM). This study aimed to investigate the effects of meal intake on the pharmacokinetic properties of henagliflozin, and to understand the excretion pathways of henagliflozin in humans.

METHODS

In this Phase I, randomized, open-label, single-dose, two-period crossover study, 12 healthy male Chinese volunteers were randomized to receive either henagliflozin 10 mg in the fasted condition followed by henagliflozin 10 mg in the fed condition, or the reverse schedule, with the two administrations separated by a washout period of at least 7 days. Samples of blood, urine, and feces were collected and analyzed for the investigation of the pharmacokinetic profile and excretion pathways in the fasted and fed conditions. Any adverse events that occurred throughout the study were recorded for tolerability assessment.

FINDINGS

After the administration of a single oral dose of henagliflozin, mean (SD) plasma AUC_0-∞ and C_max were 1200 (274) h · ng/mL and 179 (48.8) ng/mL, respectively, in the fasted state and were decreased to 971 (245) h · ng/mL and 115 (34.2) ng/mL in the fed state. The fed/fasted ratios (90% CIs) of the geometric mean values of C_max, AUC_0-t, and AUC_0-∞ were 64% (54%-76%), 80% (76%-85%), and 80% (76%-85%), respectively. The median (range) T_max was prolonged from 1.5 (1-3) hours in the fasted condition to 2 (1.5-6) hours in the fed condition. Mass-balance testing revealed that henagliflozin was eliminated primarily as the parent drug in feces and as glucuronide metabolites in urine. In the fasted state, the cumulative excretion percentages of the parent drug and its metabolites to dose in feces and urine were 40.6% and 33.9%, respectively. The values in the fed condition were changed to 50.4% and 25.5%, respectively. These findings suggest that postprandial administration decreases the absorption rate and the extent of henagliflozin exposure in humans, but has no effect on the metabolism or elimination of the drug.

IMPLICATIONS

In the present study, the consumption of a high-fat meal prior to henagliflozin administration was associated with reductions in AUC_0-∞ and C_max of 19.4% and 36.4%, respectively. However, based on the analysis of the pharmacokinetic/pharmacodynamic findings on henagliflozin, this slight change may not have clinical significance. Mass balance of henagliflozin in humans was achieved with ∼75% of the administered dose recovered in excretions within 4 days after administration whether in the fasted or fed state. These findings suggest that henagliflozin tablets can be administered with or without food.

Use of Physiologically Based Pharmacokinetic Modeling for Predicting Drug-Food Interactions: Recommendations for Improving Predictive Performance of Low Confidence Food Effect Models

Food can alter drug absorption and impact safety and efficacy. Besides conducting clinical studies, in vitro approaches such as biorelevant solubility and dissolution testing and in vivo dog studies are typical approaches to estimate a drug's food effect. The use of physiologically based pharmacokinetic models has gained importance and is nowadays a standard tool for food effect predictions at preclinical and clinical stages in the pharmaceutical industry. This manuscript is part of a broader publication from the IQ Consortium's food effect physiologically based pharmacokinetic model (PBPK) modeling working group and complements previous publications by focusing on cases where the food effect was predicted with low confidence. Pazopanib-HCl, trospium-Cl, and ziprasidone-HCl served as model compounds to provide insights into why several food effect predictions failed in the first instance. Furthermore, the manuscript depicts approaches whereby PBPK-based food effect predictions may be improved. These improvements should focus on the PBPK model functionality, especially better reflecting fasted- and fed-state gastric solubility, gastric re-acidification, and complex mechanisms related to gastric emptying of drugs. For improvement of in vitro methodologies, the focus should be on the development of more predictive solubility, supersaturation, and precipitation assays. With regards to the general PBPK modeling methodology, modelers should account for the full solubility profile when modeling ionizable compounds, including common ion effects, and apply a straightforward strategy to account for drug precipitation.

Food effects on the formulation, dosing, and administration of cannabidiol (CBD) in humans: A systematic review of clinical studies

Cannabidiol (CBD), a non-psychotropic phytocannabinoid from the Cannabis plant, is increasingly being pursued as a treatment for differing ailments. The bioavailability and pharmacokinetics of CBD are not well understood, and proper dosing schemes have not been adequately developed for its clinical use. CBD is a lipophilic molecule and exhibits low water solubility, so its formulation expectedly impacts its gastrointestinal absorption and subsequent blood plasma concentrations. In this review article, the food effects on CBD pharmacokinetics were analyzed. Clinical trials focusing on the performance of Epidiolex, the FDA-approved CBD formulation, were found in several databases and systematically analyzed in terms of administration method, dosing schedules, and patient characteristics. 44 data sets from clinical trials were found to be useful in the quantitative analysis. Following the normalization of all the pharmacokinetic data sets by dose and patient weight, CBD exhibited a much greater bioavailability in fed patients. For Epidiolex, administration in the fed state led to lower interindividual variability and more predictable pharmacokinetics. Considering all the different oral formulations of CBD, further analysis points to the main excipient of oral CBD formulations (refined sesame seed oil) as a major contributor to the dose-dependent variations in CBD pharmacokinetics, especially affecting the fasted state. We discuss the implications of these results on the downstream pharmacodynamics of endocannabinoid receptor modulation and its broad physiological implications.

Differential Effect of a Continental Breakfast on Tacrolimus Formulations With Different Release Characteristics

Food reduces tacrolimus bioavailability after immediate-release tacrolimus (IR-Tac) and after a new prolonged-release tacrolimus formulation (PR-Tac), when using a high-fat breakfast, but the effects of a continental breakfast on PR-Tac are unknown. In an open-label, 4-phase, randomized, 2-sequence, crossover pharmacokinetic trial, 36 healthy volunteers (18 females) received single 5-mg tacrolimus doses as PR-Tac and as IR-Tac fasted or with a standardized continental breakfast. Tacrolimus pharmacokinetics were analyzed using noncompartmental methods and mixed-model analysis of variance. The continental breakfast significantly decreased average tacrolimus exposure (area under the plasma concentration-time curve) with both preparations (IR-Tac, 67%; 90% confidence interval [CI], 59%-75%; P < .01; and PR-Tac, 79%; 90%CI, 70%-89%; P < .01) with a nonsignificant difference between both preparations (P = .10). The maximum concentration (C_max ) and the time to maximum concentration (t_max ) were significantly affected only after IR-Tac (C_max IR-Tac, 39%; 90%CI, 34%-45%; P < .01; and PR-Tac, 87%; 90%CI, 76%-101%; P = .11; t_max IR-Tac, 212%, 90%CI, 179%-252%; P < .01; and PR-Tac, 101%; 90%CI, 86%-120%; P = .89), which was significantly different between both preparations (P < .01). Considering switching from IR-Tac to PR-Tac, predicted dose requirements differed according to the timing of drug intake in relation to food. In conclusion, a continental breakfast decreased average tacrolimus exposure of both preparations to a similar extent. C_max and t_max were affected only after IR-Tac. The effect of a standardized continental breakfast on PR-Tac was considerably smaller than previously reported effects of a high-fat breakfast on PR-Tac.

Safety, Tolerability, Pharmacokinetics, and Food Effects on TAC-302 in Healthy Participants: Randomized, Double-Blind, Placebo-Controlled, Single-Dose and Multiple-Dose Studies

TAC-302 stimulates neurite outgrowth activity and is expected to restore urinary function in patients with lower urinary tract dysfunction. We conducted 2 phase 1, randomized, placebo-controlled studies to confirm the safety and pharmacokinetics (PK) of TAC-302 in healthy adult Japanese male volunteers. In the first-in-human single-dose study (n = 60), TAC-302 was administered at doses from 100 to 1200 mg after an overnight fast. The effects of a meal on the PK of TAC-302 400 mg were also examined. A multiple-dose study (n = 36) evaluated the effects of meal fat content on the PK of single doses of TAC-302 (100, 200, or 400 mg) and multiple doses of TAC-302 administered for 5 days (100, 200, and 400 mg twice daily). TAC-302 showed linear PK up to doses of 1200 mg in the fasting state, and across the dose range of 100-400 mg in the fed state. No accumulation of TAC-302 was observed. Food, particularly with high fat content, increased TAC-302 plasma concentrations. No differences were observed in the adverse event incidence between the TAC-302 and placebo groups in either study. TAC-302 showed a wide safety margin.

Food Effects on Oral Drug Absorption: Application of Physiologically-Based Pharmacokinetic Modeling as a Predictive Tool

The bioavailability of an orally administered small molecule is often dictated by drug-specific physicochemical characteristics and is influenced by many biological processes. For example, in fed or fasted conditions, the transit time within the gastrointestinal tract can vary, confounding the ability to predict the oral absorption. As such, the effects of food on the pharmacokinetics of compounds in the various biopharmaceutics classification system (BCS) classes need to be assessed. The consumption of food leads to physiological changes, including fluctuations in the gastric and intestinal pH, a delay in gastric emptying, an increased bile secretion, and an increased splanchnic and hepatic blood flow. Despite the significant impact of a drug's absorption and dissolution, food effects have not been fully studied and are often overlooked. Physiologically-based pharmacokinetic (PBPK) models can be used to mechanistically simulate a compound's pharmacokinetics under fed or fasted conditions, while integrating drug properties such as solubility and permeability. This review discusses the PBPK models published in the literature predicting the food effects, the models' strengths and shortcomings, as well as future steps to mitigate the current knowledge gap. We observed gaps in knowledge which limits the ability of PBPK models to predict the negative food effects and food effects in the pediatric population. Overall, the further development of PBPK models to predict food effects will provide a mechanistic basis to understand a drug's behavior in fed and fasted conditions, and will help enable the drug development process.

Overcoming the Bile Salt-Mediated Formation of Nanocolloids That Inhibit Oral Absorption of VX-985

This article describes the discovery and characterization of nanocolloidal structures formed between VX-985 (an orally administered inhibitor of hepatitis C virus protease) and the bile salt, sodium taurocholate at concentrations of the latter >4 mM. These complexes (1) distribute narrowly in size around a mean diameter of 260 nm, (2) separate from solution only with ultracentrifugation, and (3) appear to influence the absorption of VX-985 from the intestinal tract in vivo, in rodents and humans. Although the oral bioavailability of suspensions of its solid forms is poor, addition of vitamin E D-alpha-tocopherol polyethylene glycol 1000 succinate to dosing vehicles improves the fraction absorbed of the compound in vivo. In vitro characterization is compatible with the hypothesis that surfactants like D-alpha-tocopherol polyethylene glycol 1000 succinate preclude nanocolloidal structures and increase the bioavailability by increasing the rate of absorption of VX-985. This study, while specific to VX-985, provides a route to circumvent the poor oral bioavailability caused by formation of kinetically stable complexes between bile salts and drug molecules. This study also underscores the importance of characterizing aggregation phenomenon that may be observed in solubility measurements during preclinical formulation development.

Effects of High- and Low-Fat Meals on the Pharmacokinetics of Ozanimod, a Novel Sphingosine-1-Phosphate Receptor Modulator

Ozanimod (RPC1063) is an oral selective modulator of the sphingosine‐1‐phosphate 1 and 5 receptors under development for the treatment of relapsing multiple sclerosis and inflammatory bowel disease. The effects of high‐fat and low‐fat meals on the pharmacokinetics (PK) of a single oral dose of ozanimod were evaluated in 24 healthy volunteers in a randomized, open‐label crossover trial. Each subject received a 1‐mg dose of ozanimod hydrochloride under 3 meal conditions (fasted, high‐fat, and low‐fat), each separated by 7 days. Mean plasma concentration–time profiles for ozanimod and its active metabolites (RP101988 [major], RP101075 [minor]) were similar under all 3 conditions. Moreover, all PK parameters for ozanimod, RP101988, and RP101075 were similar under the 3 meal conditions. The 90% confidence intervals (CIs) for the ratios of geometric least‐squares mean (fed/fasted) were within the equivalence limits of 0.80 to 1.25 for area under the concentration–time curve from time 0 to infinity (AUC_0–∞) and maximum plasma concentration (C_max) for ozanimod, RP101988, and RP101075, except for the high‐fat effect on RP101075 C_max (90%CI, 0.76–0.88). Given this lack of a food effect on the exposure of ozanimod and its active metabolites, ozanimod can be taken without regard to meals.

Analysis of Nonlinear Pharmacokinetics of a Highly Albumin-Bound Compound: Contribution of Albumin-Mediated Hepatic Uptake Mechanism

The cause of nonlinear pharmacokinetics (PK) (more than dose-proportional increase in exposure) of a urea derivative under development (compound A: anionic compound [pKa: 4.4]; LogP: 6.5; and plasma protein binding: 99.95%) observed in a clinical trial was investigated. Compound A was metabolized by CYP3A4, UGT1A1, and UGT1A3 with unbound K_m of 3.3-17.8 μmol/L. OATP1B3-mediated uptake of compound A determined in the presence of human serum albumin (HSA) showed that unbound K_m and V_max decreased with increased HSA concentration. A greater decrease in unbound K_m than in V_max resulted in increased uptake clearance (V_max/unbound K_m) with increased HSA concentration, the so-called albumin-mediated uptake. At 2% HSA concentration, unbound K_m was 0.00657 μmol/L. A physiologically based PK model assuming saturable hepatic uptake nearly replicated clinical PK of compound A. Unbound K_m for hepatic uptake estimated from the model was 0.000767 μmol/L, lower than the in vitro unbound K_m at 2% HSA concentration, whereas decreased K_m with increased concentration of HSA in vitro indicated lower K_m at physiological HSA concentration (4%-5%). In addition, unbound K_m values for metabolizing enzymes were much higher than unbound K_m for OATP1B3, indicating that the nonlinear PK of compound A is primarily attributed to saturated OATP1B3-mediated hepatic uptake of compound A.

Bioavailability of a dexlansoprazole delayed-release orally disintegrating tablet: effects of food and mode of administration

Background

Dexlansoprazole is a proton pump inhibitor (PPI) approved for use in dual delayed-release capsule and orally disintegrating tablet (ODT) formulations.

Aim

To assess effects of food, water, and route of administration on the bioavailability of dexlansoprazole 30-mg ODT.

Methods

Two separate open-label, phase 1, single-dose crossover studies were conducted in healthy adults. In study 1, pharmacokinetic parameters were analyzed in participants receiving dexlansoprazole ODT in a fed or fasted state with and without water. In study 2, the bioavailability of dexlansoprazole after administration via oral syringe or nasogastric (NG) tube, or after swallowing intact with water was compared to ODT administration in the fasted state, swallowed without water. Blood samples for determining dexlansoprazole plasma concentrations and pharmacokinetic parameter estimates were collected before and after dosing.

Results

Equivalent values for area under the plasma concentration–time curve (AUC) were observed in the fed and fasted states, but the maximum observed plasma concentration (C_max) was 38% lower in the fed state; therefore, bioequivalence was not achieved. A water rinse following standard ODT administration decreased dexlansoprazole bioavailability, with lower C_max and AUC values than when ODT was administered without a water rinse. Bioequivalence was demonstrated when comparing the alternative routes of administration, including via oral syringe or NG tube with standard ODT administration. Unlike with a water rinse, bioequivalence to standard ODT administration (i.e., without water) was demonstrated when swallowing the ODT intact with water. Rates of adverse events were comparable irrespective of administration route in the fasted state (6.7%–9.3%) and were 12% higher in the fed state than in the fasted state.

Conclusion

The AUC from the dexlansoprazole ODT was equivalent when administered in the fed and fasted states. Equivalent systemic exposure to dexlansoprazole was achieved regardless of the administration route.

Meal Effects Confound Attempts to Counteract Rabeprazole-Induced Hypochlorhydria Decreases in Atazanavir Absorption

PURPOSE

Clinically relevant pharmacokinetic interactions exist between gastric acid-reducing agents and certain weakly basic drugs that rely on acidic environments for optimal oral absorption. In this study, we examine whether the administration of betaine hydrochloride under fed conditions can enhance the absorption of atazanavir, an HIV-1 protease inhibitor, during pharmacologically-induced hypochlorhydria.

METHODS

In this randomized, single-dose, 3 period, crossover study healthy volunteers received ritonavir-boosted atazanavir (atazanavir/ritonavir 300/100 mg) alone, following pretreatment with the proton pump inhibitor rabeprazole (20 mg twice daily), and with 1500 mg of betaine HCl after rabeprazole pretreatment. Atazanavir was administered with a light meal and gastric pH was monitored using the Heidelberg Capsule.

RESULTS

Pretreatment with rabeprazole resulted in significant reductions in atazanavir C_max (p < 0.01) and AUC_0-last (p < 0.001) (71 and 70%, respectively), and modest decreases in ritonavir C_max and AUC_last (p < 0.01) (40% and 41%, respectively). The addition of betaine HCl restored 13% of ATV C_max and 12% of AUC_last lost due to rabeprazole.

CONCLUSIONS

The co-administration of rabeprazole with atazanavir resulted in significant decreases in atazanavir exposure. The addition of betaine HCl did not sufficiently mitigate the loss of ATV exposure observed during RAB-induced hypochlorhydria. Meal effects lead to a marked difference in the outcome of betaine HCl on atazanavir exposure than we previously reported for dasatanib under fasting conditions.

Pharmacokinetics, Safety, and Tolerability of Single and Multiple Doses of ABT-493: A First-In-Human Study

ABT-493 is a hepatitis C virus nonstructural protein 3/4A protease inhibitor with pangenotypic antiviral activity. This study investigated the pharmacokinetics, safety, and tolerability of single and multiple ascending doses of ABT-493 and the effect of food and ritonavir coadministration on ABT-493 pharmacokinetics in healthy adults. In the blinded, randomized, placebo-controlled phase 1 single- and multiple-dose portions of the study, ABT-493 25-800 mg were evaluated as single doses, and 200, 400, and 800 mg were evaluated as multiple doses. The effect of food and ritonavir was assessed in a crossover unblinded fashion. ABT-493 pharmacokinetic parameters were estimated using noncompartmental methods. ABT-493 25-800 mg showed a greater than dose-proportional increase in exposures. Minimal accumulation (≤15%) was observed after ABT-493 200- and 400-mg multiple dosing; higher accumulations (approximately 80%) were observed after the 800-mg dose. ABT-493 harmonic mean half-life was 6-9 hours. Food had a minimal effect on ABT-493 exposures. All adverse events were assessed by the investigator as mild to moderate in severity, no serious adverse events were reported, and no subjects discontinued from the study. No clinically significant laboratory tests, vital signs, or electrocardiogram values were reported. A maximum tolerated dose was not reached.

The Effect of a High-Fat Meal on the Pharmacokinetics of Ixazomib, an Oral Proteasome Inhibitor, in Patients With Advanced Solid Tumors or Lymphoma

Ixazomib is the first oral proteasome inhibitor to be investigated in the clinic. This clinical study assessed whether the pharmacokinetics of ixazomib would be altered if administered after a high‐calorie, high‐fat meal. In a 2‐period, 2‐sequence, crossover study design, adult patients with advanced solid tumors or lymphoma received a 4‐mg oral dose of ixazomib as immediate‐release capsules on day 1 without food (fasted, administered following an overnight fast) or with food (fed, following consumption of a high‐calorie, high‐fat meal), followed by another dose on day 15 in the alternate food intake condition (fasted to fed or fed to fasted). Twenty‐four patients were enrolled; of these, 15 were included in the pharmacokinetic‐evaluable population. Administration of ixazomib after a high‐fat meal reduced both the rate and extent of absorption of ixazomib. Under fed conditions, the median time to peak plasma concentration (T_max) of ixazomib was delayed by approximately 3 hours compared with administration in the fasted state (1.02 hours vs 4.0 hours), and there was a 28% reduction in total systemic exposure (area under the curve, AUC) and a 69% reduction in peak plasma concentration (C_max). Together, the results support the administration of ixazomib on an empty stomach, at least 1 hour before or at least 2 hours after food. These recommendations are reflected in the United States Prescribing Information for ixazomib (clinicaltrials.gov identifier NCT01454076).

Glyceollin Effects on MRP2 and BCRP in Caco-2 Cells, and Implications for Metabolic and Transport Interactions

Glyceollins are phytoalexins produced in soybeans under stressful growth conditions. On the basis of prior evaluations, they show potential to treat multiple diseases, including certain cancers, Type 2 diabetes, and cardiovascular conditions. The aim of the present study was to expand on recent studies designed to initially characterize the intestinal disposition of glyceollins. Specifically, studies were undertaken in Caco-2 cells to evaluate glyceollins' effects on apical efflux transporters, namely, MRP2 and BCRP, which are the locus of several intestinal drug-drug and drug-food interactions. 5- (and 6)-carboxy-2',7'-dichloroflourescein (CDF) was used to provide a readout on MRP2 activity, whereas BODIPY-prazosin provided an indication of BCRP alteration. Glyceollins were shown to reverse MRP2-mediated CDF transport asymmetry in a concentration-dependent manner, with activity similar to the MRP2 inhibitor, MK-571. Likewise, they demonstrated concentration-dependent inhibition of BCRP-mediated efflux of BODIPY-prazosin with a potency similar to that of Ko143. Glyceollin did not appreciably alter MRP2 or BCRP expression following 24 h of continuous exposure. The possibility that glyceollin mediated inhibition of genistein metabolite efflux by either transporter was evaluated. However, results demonstrated an interaction at the level of glyceollin inhibition of genistein metabolism rather than inhibition of metabolite transport.

Cocrystal Solubilization in Biorelevant Media and its Prediction from Drug Solubilization

This work examines cocrystal solubility in biorelevant media (FeSSIF, fed-state simulated intestinal fluid), and develops a theoretical framework that allows for the simple and quantitative prediction of cocrystal solubilization from drug solubilization. The solubilities of four hydrophobic drugs and seven cocrystals containing these drugs were measured in FeSSIF and in acetate buffer at pH 5.00. In all cases, the cocrystal solubility (Scocrystal ) was higher than the drug solubility (Sdrug ) in both buffer and FeSSIF; however, the solubilization ratio of drug, SRdrug = (SFeSSIF /Sbuffer )drug , was not the same as the solubilization ratio of cocrystal, SRcocrystal = (SFeSSIF /Sbuffer )cocrystal , meaning drug and cocrystal were not solubilized to the same extent in FeSSIF. This highlights the potential risk of anticipating cocrystal behavior in biorelevant media based on solubility studies in water. Predictions of SRcocrystal from simple equations based only on SRdrug were in excellent agreement with measured values. For 1:1 cocrystals, the cocrystal solubilization ratio (SR) can be obtained from the square root of the drug SR. For 2:1 cocrystals, SRcocrystal is found from (SRdrug )(2/3) . The findings in FeSSIF can be generalized to describe cocrystal behavior in other systems involving preferential solubilization of a drug such as surfactants, lipids, and other drug solubilizing media.

Effects of Food Intake on the Relative Bioavailability of Amifampridine Phosphate Salt in Healthy Adults

PURPOSE

Amifampridine (3,4-diaminopyridine) has been approved in the European Union for the treatment of Lambert-Eaton myasthenic syndrome. Amifampridine has a narrow therapeutic index, and supratherapeutic exposure has been associated with dose-dependent adverse events, including an increased risk for seizure. This study assessed the effect of food on the relative bioavailability of amifampridine in healthy subjects and informed on conditions that can alter exposure.

METHODS

This randomized, open-labeled, 2-treatment, 2-period crossover study enrolled 47 healthy male and female subjects. Subjects were randomly assigned to receive 2 single oral doses of amifampridine phosphate salt (20 mg base equivalents per dose) under fed or fasted conditions separated by a washout period. Blood and urine samples for pharmacokinetic analyses were taken before and after dosing. Plasma concentrations of amifampridine and an inactive 3-N-acetyl metabolite were determined. The relative bioavailability values of amifampridine and metabolite were assessed based on the plasma PK parameters AUC0-∞, AUC0-t, and Cmax in the fed and fasted states using noncompartmental pharmacokinetic analysis. Parent drug and metabolite excretion were calculated from urinary concentrations. A food effect on bioavailability would be established if the 90% CI of the ratio of population geometric mean value of AUC0-∞, AUC0-t, or Cmax between fed and fasted administration was not within the bioequivalence range of 80% to 125%. Tolerability was assessed based on adverse-event reporting, clinical laboratory assessments, physical examination including vital sign measurements, 12-lead ECG, and concurrent medication use.

FINDINGS

Food slowed and somewhat decreased the absorption of amifampridine. There was a decrease in exposure (Cmax, 44%; AUC, 20%) after oral administration of amifampridine phosphate salt in the presence of food, and mean Tmax was 2-fold longer in the fed state. The extent of exposure and plasma elimination half-life of the major metabolite was greater than those of amifampridine in the fed and fasted conditions. Mean AUCs in the fed and fasted states were slightly greater in women than men, with no difference in mean Cmax. Orally administered amifampridine was renally eliminated (>93%) as the parent compound and metabolite within 24 hours. Single oral doses of 20 mg of amifampridine phosphate salt were considered well tolerated in both the fed and fasted conditions. High intersubject variability (%CVs, >30%) in amifampridine pharmacokinetic parameter values was observed.

IMPLICATIONS

At the intended dose under fasting conditions, amifampridine exposure may be increased. European Union Drug Regulating Authorities Clinical Trials identifier: 2011-000596-13.

Computational Fluid Dynamics Simulation of Hydrodynamics and Stresses in the PhEur/USP Disintegration Tester Under Fed and Fasted Fluid Characteristics

Disintegration of oral solid dosage forms is a prerequisite for drug dissolution and absorption and is to a large extent dependent on the pressures and hydrodynamic conditions in the solution that the dosage form is exposed to. In this work, the hydrodynamics in the PhEur/USP disintegration tester were investigated using computational fluid dynamics (CFD). Particle image velocimetry was used to validate the CFD predictions. The CFD simulations were performed with different Newtonian and non-Newtonian fluids, representing fasted and fed states. The results indicate that the current design and operating conditions of the disintegration test device, given by the pharmacopoeias, are not reproducing the in vivo situation. This holds true for the hydrodynamics in the disintegration tester that generates Reynolds numbers dissimilar to the reported in vivo situation. Also, when using homogenized US FDA meal, representing the fed state, too high viscosities and relative pressures are generated. The forces acting on the dosage form are too small for all fluids compared to the in vivo situation. The lack of peristaltic contractions, which generate hydrodynamics and shear stress in vivo, might be the major drawback of the compendial device resulting in the observed differences between predicted and in vivo measured hydrodynamics.

The Nutraceutical Bioavailability Classification Scheme: Classifying Nutraceuticals According to Factors Limiting their Oral Bioavailability

The oral bioavailability of a health-promoting dietary component (nutraceutical) may be limited by various physicochemical and physiological phenomena: liberation from food matrices, solubility in gastrointestinal fluids, interaction with gastrointestinal components, chemical degradation or metabolism, and epithelium cell permeability. Nutraceutical bioavailability can therefore be improved by designing food matrices that control their bioaccessibility (B*), absorption (A*), and transformation (T*) within the gastrointestinal tract (GIT). This article reviews the major factors influencing the gastrointestinal fate of nutraceuticals, and then uses this information to develop a new scheme to classify the major factors limiting nutraceutical bioavailability: the nutraceutical bioavailability classification scheme (NuBACS). This new scheme is analogous to the biopharmaceutical classification scheme (BCS) used by the pharmaceutical industry to classify drug bioavailability, but it contains additional factors important for understanding nutraceutical bioavailability in foods. The article also highlights potential strategies for increasing the oral bioavailability of nutraceuticals based on their NuBACS designation (B*A*T*).

Mechanism of chemical degradation and determination of solubility by kinetic modeling of the highly unstable sesquiterpene lactone nobilin in different media

The objective of this work was first to investigate the chemical degradation of the sesquiterpene lactone nobilin and determine its solubility under conditions of concurrent degradation for partially amorphous starting material; second, to determine the effect of biorelevant media used in the in vitro measurement of intestinal absorption on degradation and solubility of nobilin. Purely aqueous medium (aq-TMCaco ), fasted and fed state simulated intestinal fluid (FaSSIF-TMCaco and FeSSIF-TMCaco ), and two liposomal formulations (LiposomesFaSSIF and LiposomesFeSSIF ) with the same lipid concentration as FaSSIF-TMCaco and FeSSIF-TMCaco were used. Degradation products were identified by nuclear magnetic resonance and X-ray crystallography and the order of reaction kinetics was determined. Solubility was deduced with a mathematical model encompassing dissolution, degradation, and reprecipitation kinetics that took into account particle size distribution of the solid material. Degradation mechanism of nobilin involved water-catalyzed opening of the lactone ring and transannular cyclization resulting in five degradation products. Degradation followed first-order kinetics in aq-TMCaco and FaSSIF-TMCaco , and higher-order kinetics in FeSSIF-TMCaco and the two liposomal formulations, whereas degradation in the latter media was diminished. Solubility of nobilin increased in the order: aq-TMCaco < FaSSIF-TMCaco , < LiposomesFaSSIF < FeSSIF-TMCaco < LiposomesFeSSIF . Improvement of stability and solubility was consistent with the incorporation of the nobilin molecule into colloidal lipid particles. The developed kinetic model is proposed to be a useful tool for deducing solubility under dynamic conditions.

Suitability of a minipig model in assessing clinical bioperformance of matrix and multiparticulate extended-release formulations for a BCS class III Drug development candidate

Preclinical studies in dogs are often employed as part of formulation screening process. However, the shorter transit time and colonic length in dogs may result in underestimation of absorption, especially for extended-release (ER) formulations. In the recent years, minipigs have attracted attention as an alternative animal model. However reports on studies with ER formulations are limited. In this manuscript, we report the first comprehensive comparison of minipig and clinical data for two types of ER formulations. Matrix tablets and multiparticulates in capsules of a BCS Class III compound were tested in the Yucatan minipig model. The relative performance of the formulations in minipigs in the fasted state was reasonably aligned with the clinical observations. The minipig model was able to rank order the formulations, reflecting the targeted release rate, in a manner consistent with the clinical data. Minipigs also reflected the loss of bioavailability relative to the immediate-release formulation. A level C in vitro/in vivo correlation was demonstrated for both the minipig and clinical data. However, an assessment of food effect in the minipig model appeared challenging, especially for the matrix formulation for which a negative food effect was observed in minipigs compared with the positive food effect in the clinic.

Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality

AIMS

To determine the absolute bioavailability, dose proportionality and the effects of food on the pharmacokinetics of single oral doses of sildenafil citrate.

METHODS

Three open-label, randomized crossover studies were conducted in healthy male subjects. Absolute bioavailability was determined by comparing pharmacokinetic data after administration of single oral and intravenous 50-mg doses of sildenafil (n=12 subjects). Food effects were examined by comparing pharmacokinetic data for sildenafil and its primary circulating metabolite, UK-103,320, after administration of a single oral 100-mg dose in the fasted and fed states (n=34 subjects). Dose proportionality was assessed from pharmacokinetic data obtained after administration of four single oral doses of sildenafil (25, 50, 100 and 200 mg) to 32 subjects. The safety and tolerability of sildenafil were also assessed in all of these studies.

RESULTS

The calculated absolute oral bioavailability of sildenafil was 41% (90% CI: 36--47). Food slowed the rate of absorption, delaying mean tmax by approximately 1 h and reducing Cmax by 29% (90% CI: 19--38). Systemic exposure, as assessed by the mean area under the plasma concentration--time curve (AUC), was reduced by 11% (90% CI: 6--16). These food effects were not considered to be of clinical significance. There was statistical evidence of nonproportionality in Cmax and AUC over the dose range 25--200 mg. However the degree of nonproportionality was small, with predicted increases in Cmax and AUC of 2.2- and 2.1-fold, respectively, for a doubling in dose, and was thought to be clinically nonsignificant. Sildenafil was well tolerated in the three studies; the majority of adverse events were mild and transient.

CONCLUSIONS

Sildenafil had a mean absolute bioavailability of 41%. Food caused small reductions in the rate and extent of systemic exposure; these reductions are unlikely to be of clinical significance. Across the dose range of 25--200 mg, systemic exposure increased in a slightly greater than dose-proportional manner.