Drug, meal and formulation interactions influencing drug absorption after oral administration. Clinical implications

Impact of structured personal on-site patient education on low posaconazole plasma concentrations in patients with haematological malignancies

Low posaconazole plasma concentrations (PPCs) are associated with breakthrough invasive mould infections among patients with haematological malignancies. This study evaluated the influence of structured personal on-site patient education on low PPCs. The study was conducted from July 2012 to May 2013 at the Division of Hematology, Medical University Hospital of Graz (Graz, Austria). PPCs were measured in all patients with haematological malignancies receiving the drug prophylactically. Concentrations above the target of 0.5 mg/L were defined as satisfactory and those below this concentration as low. In patients with low PPCs, structured personal on-site education regarding the intake of posaconazole (e.g. intake with fatty/acid food, prevention of nausea and vomiting) was performed. In total, 258 steady-state PPCs were measured in 65 patients [median PPC 0.59 mg/L, interquartile range 0.25-0.92 mg/L; 141/258 (54.7%) satisfactory]. Diarrhoea was the strongest predictor of low PPCs in the multivariate analysis. Initial steady-state PPCs were sufficient in 29 patients and low in 36 patients. Of the 36 patients with low initial steady-state PPCs, 8 were either discharged or antifungal therapy was modified before a follow-up PPC was obtained; in the remaining 28 patients, personal on-site education was performed. In 12/28 patients (43%) the personal on-site education led to sufficient levels, whilst in 16 (57%) PPCs stayed below the target, although increasing from <0.2 mg/L to >0.3 mg/L in 6 of these patients. In conclusion, personal education appears to be a promising tool to increase low PPCs.

Perspective and potential of oral lipid-based delivery to optimize pharmacological therapies against cardiovascular diseases

Cardiovascular diseases (CVDs) remain the major cause of morbidity and mortality globally. Despite the large number of cardiovascular drugs available for pharmacological therapies, factors limiting the efficient oral use are identified, including low water solubility, pre-systemic metabolism, food intake effects and short half-life. Numerous in vivo proof-of-concepts studies are presented to highlight the viability of lipid-based delivery to optimize the oral delivery of cardiovascular drugs. In particular, the key performance enhancement roles of oral lipid-based drug delivery systems (LBDDSs) are identified, which include i) improving the oral bioavailability, ii) sustaining/controlling drug release, iii) improving drug stability, iv) reducing food intake effect, v) targeting to injured sites, and vi) potential for combination therapy. Mechanisms involved in achieving these features, range of applicability, and limits of available systems are detailed. Future research and development efforts to address these issues are discussed, which is of significant value in directing future research work in fostering translation of lipid-based formulations into clinical applications to reduce the prevalence of CVDs.

Application of physiologically based absorption modeling to formulation development of a low solubility, low permeability weak base: mechanistic investigation of food effect

Physiologically based pharmacokinetic (PBPK) modeling has been broadly used to facilitate drug development, hereby we developed a PBPK model to systematically investigate the underlying mechanisms of the observed positive food effect of compound X (cpd X) and to strategically explore the feasible approaches to mitigate the food effect. Cpd X is a weak base with pH-dependent solubility; the compound displays significant and dose-dependent food effect in humans, leading to a nonadherence of drug administration. A GastroPlus Opt logD Model was selected for pharmacokinetic simulation under both fasted and fed conditions, where the biopharmaceutic parameters (e.g., solubility and permeability) for cpd X were determined in vitro, and human pharmacokinetic disposition properties were predicted from preclinical data and then optimized with clinical pharmacokinetic data. A parameter sensitivity analysis was performed to evaluate the effect of particle size on the cpd X absorption. A PBPK model was successfully developed for cpd X; its pharmacokinetic parameters (e.g., C max, AUCinf, and t max) predicted at different oral doses were within ±25% of the observed mean values. The in vivo solubility (in duodenum) and mean precipitation time under fed conditions were estimated to be 7.4- and 3.4-fold higher than those under fasted conditions, respectively. The PBPK modeling analysis provided a reasonable explanation for the underlying mechanism for the observed positive food effect of the cpd X in humans. Oral absorption of the cpd X can be increased by reducing the particle size (<100 nm) of an active pharmaceutical ingredient under fasted conditions and therefore, reduce the cpd X food effect correspondingly.

From bench to humans: formulation development of a poorly water soluble drug to mitigate food effect

This study presents a formulation approach that was shown to mitigate the dramatic food effect observed for a BCS Class II drug. In vitro (dissolution), in vivo (dog), and in silico (GastroPlus®) models were developed to understand the food effect and design strategies to mitigate it. The results showed that such models can be used successfully to mimic the clinically observed food effect. GastroPlus® modeling showed that food effect was primarily due to the extensive solubilization of the drug into the dietary lipid content of the meal. Several formulations were screened for dissolution rate using the biorelevant dissolution tests. Surfactant type and binder amount were found to play a significant role in the dissolution rate of the tablet prototypes that were manufactured using a high-shear wet granulation process. The performance of the lead prototypes (exhibiting best in vitro dissolution performance) was tested in dogs and human subjects. A new formulation approach, where vitamin E TPGS was included in the tablet formulation, was found to mitigate the food effect in humans.

Effect of food on the pharmacokinetic properties of the oral sarpogrelate hydrochloride controlled-release tablet in healthy male Korean subjects

BACKGROUND

A new controlled-release formulation of sarpogrelate, a 5-hydroxytryptamine receptor subtype 2 antagonist that blocks serotonin-induced platelet aggregation, has been developed for once-daily administration.

OBJECTIVE

This study evaluated the effect of food on the pharmacokinetic properties of controlled-release sarpogrelate (sarpogrelate CR) in healthy volunteers.

METHODS

A randomized, open-label, two-period, two-treatment crossover study was performed in healthy male Korean subjects. Following an overnight fast, a single dose of sarpogrelate CR 300 mg was administered either in the fasted condition or immediately after a high-fat breakfast. Pharmacokinetic parameters were calculated using a noncompartmental analysis. Tolerability was determined using clinical laboratory testing and physical examination, including vital sign measurements, electrocardiography, and interviews with the volunteers regarding adverse events (AEs).

RESULTS

A total of 24 healthy subjects were enrolled, 23 of whom completed the study (mean [range] age, 26 years [21-45]; weight, 68.1 kg [56.0-79.9]; body mass index, 22.1 kg/m(2) [18.8-25.0]). Sarpogrelate C(max) and AUC(last) were decreased In the fed condition compared with those in the fasted condition, with geometric mean ratios (90% CI) of 0.4868 (0.4041-0.5864) and 0.7394 (0.6809-0.8028), respectively. T(max) was delayed from 0.75 to 4.0 hours after a high-fat meal, but the fed condition exhibited a similar elimination profile to that of the fasted condition. The most commonly reported AE was headache (n = 2), and other AEs were reported in 1 subject each. All of the AEs were considered mild in intensity, and the participants recovered without treatment.

CONCLUSIONS

Compared with the administration of sarpogrelate CR 300 mg in the fasted condition, administration with food was associated with a decreased rate and extent of absorption, as assessed by C(max) and AUC(last), respectively. The drug was well-tolerated by the healthy subjects in this study.

Negligible pharmacokinetic interaction of red ginseng and antihypertensive agent amlodipine in Sprague-Dawley rats

Red ginseng (RG) is the top-selling functional food in Korea, but is not recommended for use in hypertensive patients. This study was performed to determine the pharmacokinetic (PK) interaction between RG and amlodipine, an antihypertensive drug. RG (0, 0.5, 1, or 2 g/kg/d) was administered orally for 2 wk, and then amlodipine (10 mg/kg) was given orally, to Sprague-Dawley (SD) rats. Blood was collected at 0.08, 0.25, 1, 1.5, 2, 3, 6, 12, and 24 h after amlodipine administration. In intravenous (iv) study, RG (0, 1, or 2 g/kg/d) was administered orally to SD rats for 2 wk, followed by amlodipine (2 mg/kg) intravenously (iv). Plasma concentrations of amlodipine were analyzed using a high-pressure liquid chromatography-tandem mass system (LC-MS/MS). Oral administration of amlodipine produced an increase of time to maximum plasma concentration (tmax: 2.6, 4.1, 8.3, and 8.9 h at 0, 0.5, 1, and 2 g/kg/d, respectively), and a decrease of maximum plasma concentration (Cmax: 278.5, 212.4, 232.1, and 238.7 ng/ml at 0, 0.5, 1, and 2 g/kg/d, respectively.). However, the area under the concentration-time curve from time 0 to 24 h measurable concentration (AUC0-24 h was 3487.4, 2895.4, 3158.2, and 3495 ng/h/ml at 0, 0.5, 1, and 2 g/kg/d respectively) was not significantly changed among the different dose groups. Administration of amlodipine iv produced no significant changes in the apparent terminal half-life, volume of distribution, and AUC0-24 hr among the different dose groups. These results suggest that RG induced negligible influence on amlodipine pharmacokinetically in rats.

Excipient foods: designing food matrices that improve the oral bioavailability of pharmaceuticals and nutraceuticals

The oral bioavailability of many lipophilic bioactive agents (pharmaceuticals and nutraceuticals) is limited due to various physicochemical and physiological processes. Excipient foods can be designed to improve the oral bioavailability of these bioactive agents.

Absolute bioavailability and effect of formulation change, food, or elevated pH with rabeprazole on cobimetinib absorption in healthy subjects

Cobimetinib is a potent and highly selective inhibitor of MEK1/2. Since cobimetinib exhibited absorption variability in cancer patients, a series of single-dose studies in healthy subjects were conducted to determine absolute bioavailability and elucidate potential effects of formulation, food, and elevated gastric pH on cobimetinib bioavailability. Three crossover trials were performed with a 20 mg cobimetinib oral dose: absolute bioavailability using a 2 mg intravenous infusion (n = 13), relative bioavailability of tablets versus capsules and food effect (n = 20), and drug interaction with a proton pump inhibitor (20 mg of rabeprazole daily for 5 days prior to cobimetinib administration; n = 20). Absolute bioavailability of cobimetinib was 46.2% (24.2, CV %), likely due to metabolism rather than incomplete absorption. The mean systemic clearance of cobimetinib was low (11.7 L/h [28.2, CV %]). Administration of cobimetinib tablets with a high-fat meal delayed drug absorption (prolonged tmax) but had no statistically significant effect on cobimetinib exposure (Cmax and AUC0-∞). Tablet and capsule formulations of cobimetinib showed comparable exposures. Cobimetinib exhibited delayed absorption (tmax) in the presence of rabeprazole, with no statistically significant effects on drug exposure (Cmax and AUC0-∞) in the fasted state. In conclusion, cobimetinib oral absorption was not affected by change in formulation, food, or elevated gastric pH.

Influence of food on pharmacokinetics of zolpidem from fast dissolving sublingual zolpidem tartrate tablets

Ingesting food can impact the pharmacokinetics of sedative-hypnotic drugs. A buffered zolpidem sublingual tablet (ZST) recently became available for the treatment of middle-of-the-night awakening. In this randomized, open-label, single-site study, the pharmacokinetic profile of ZST was evaluated when administered while fasting and following a standard high-fat meal (fed state). Healthy adults aged 18-64 years received a single morning dose of 3.5 mg ZST in the fed or fasting state. From 20 min to 3 h post-dose, zolpidem plasma levels were lower in the fed state compared to the fasting state. After 4 h post-dose (corresponding to "morning wake time"), higher zolpidem plasma levels were evident in the fed state. Area under the concentration-time curve (AUC) values for the 0-8 h interval were 160 ng/mL h in the fed state and 203 ng/mL h in the fasting state (P < .001). In the fed versus fasting states, Cmax was 32.0 ng/mL versus 57.3 ng/mL (P < .001), respectively, and Tmax was 3.0 h versus 0.92 h (P < .001), respectively. Together these data suggest that administration of ZST in the fed state is not optimal for maximizing the likelihood of therapeutic benefit and minimizing the probability of residual sedation.

Utility of physiologically based modeling and preclinical in vitro/in vivo data to mitigate positive food effect in a BCS class 2 compound

Physiologically based pharmacokinetic (PBPK) modeling has become a useful tool to estimate the performance of orally administrated drugs. Here, we described multiple in silico/in vitro/in vivo tools to support formulation development toward mitigating the positive food effect of NVS123, a weak base with a pH-dependent and limited solubility. Administered orally with high-fat meal, NVS123 formulated as dry filled capsules displayed a positive food effects in humans. Three alternative formulations were developed and assessed in in vitro and in vivo preclinical and/or clinical studies. By integrating preclinical in vitro and in vivo data, the PBPK model successfully estimated the magnitude of food effects and the predicted values were within ± 30% of the observed results. A model-guided parameter sensitivity analysis illustrated that enhanced solubility and longer precipitation times under fed condition were the main reason for enhanced NVS123's exposure in presence of food. Eventually, exposure after an amorphous formulation was found to be not significantly altered because of remarkably enhanced intestinal solubility and reduced precipitation. Gastroplus population simulations also suggested that the amorphous formulation is promising in mitigating a clinically significant food effect. Overall, these efforts supported the rationale of clinical investigation of the new formulation, and more importantly, highlighted a practical application of PBPK modeling solving issues of undesirable food effects in weakly basic compounds based on preclinical in vitro/in vivo data.

Effect of food on the pharmacokinetics of lurasidone: results of two randomized, open-label, crossover studies

OBJECTIVE

This study aimed to investigate the effect of prandial status and caloric and fat composition of meals on the pharmacokinetics of lurasidone.

METHODS

Two randomized, open-label, crossover studies were conducted in clinically stable adults with schizophrenia or schizoaffective disorder. Study 1 (n = 16) evaluated the effect of fasting and three meal types (100 kcal/medium fat, 200 kcal/medium fat, and 800-1000 kcal/high fat), and Study 2 (n = 26) evaluated the effect of fasting and five meal types (350 kcal/high fat, 500 kcal/low fat, 500 kcal/high fat, 800-1000 kcal/low fat, and 800-1000 kcal/high fat) on the bioavailability of lurasidone. Subjects received lurasidone 120 mg once daily. Maximum serum concentration (Cmax ) and area under the serum concentration-time curve over the dosing interval (AUC0-tau ) were determined on Day 5 for each meal type.

RESULTS

In Study 1, the geometric mean Cmax in the fasted state was 56.7 ng/mL compared with 123.0 ng/mL for the 800- to 1000-kcal meal; mean AUC0-tau was 360.0 versus 752.4 ng·h/mL (both p < 0.001). Lurasidone exposure following meals containing 100 and 200 kcal was substantially lower than with meals containing 800-1000 kcal. In Study 2, the geometric mean Cmax was 52.9 ng/mL in the fasted state, 161 ng/mL for the 350-kcal/high-fat meal, 135 ng/mL for the 500-kcal/high-fat meal, and 131 ng/mL for the 800- to 1000-kcal/high-fat meal; mean AUC0-tau was 390, 743, 727, and 769 ng·h/mL, respectively. For all comparisons, the 90% confidence interval of the fed to fasted ratios indicated nonequivalence. Lurasidone exposure was similar following meals containing 350-1000 kcal and was independent of fat content.

CONCLUSION

Lurasidone should be administered with food-at least 350 kcal-to ensure maximum exposure.

Effects of food intake on the pharmacokinetic properties of mirabegron oral controlled-absorption system: a single-dose, randomized, crossover study in healthy adults

BACKGROUND

Mirabegron is a β3-adrenoceptor agonist used for the treatment of overactive bladder. Mirabegron is formulated as an extended-release tablet using oral controlled-absorption system (OCAS) technology.

OBJECTIVE

This study was designed to assess the effects of food on the pharmacokinetic properties of mirabegron OCAS in accordance with regulatory requirements to support dosing recommendations.

METHODS

In this single-dose, randomized, open-label, 3-period, parallel-dose-group, crossover study, mirabegron OCAS 50 or 100 mg was administered orally to healthy adult subjects in the fasted state or after a high- or low-fat breakfast. Dose administrations were separated by a washout period of at least 10 days. Blood samples were drawn up to 96 hours after dosing, and plasma concentrations of mirabegron were analyzed by LC/MS-MS. PK properties were determined using noncompartmental methods. Primary end points for the assessment of food effects were Cmax and AUC0-∞. For tolerability assessment, adverse events (AEs) were monitored using investigators' questionnaires and subjects' spontaneous reports, vital sign measurements, hematology, clinical chemistry, and ECG.

RESULTS

Thirty-eight subjects (male, 50%; mean age, 32.1 years; mean weight, 77.3 kg; race, 76.3% white) were enrolled in the 50-mg dose group and 38 subjects (male, 52.6%; mean age, 30.9 years; mean weight, 74.5 kg; race, 63.2% white) in the 100-mg dose group. With either fed condition or dose, the 90% CIs for the fed/fasted ratios of both Cmax and AUC0-∞ of mirabegron fell below the predetermined range for bioequivalence (80.0%-125.0%), suggesting that food had no effect on exposure to mirabegron OCAS. With the 50-mg dose, mirabegron Cmax was reduced by 45% with a high-fat breakfast compared with fasted conditions (geometric mean ratio [GMR], 54.8% [90% CI, 43.7%-68.6%]) and AUC0-∞, by 17% (GMR, 83.2% [90% CI, 74.2%-93.4%]). With the 100-mg dose, mirabegron Cmax and AUC0-∞ were reduced by 39% (GMR, 61.3% [90% CI, 47.8%-78.7%]) and 18% (82.4% [72.6%-93.5%]), respectively, after a high-fat breakfast. With the 50-mg dose, mirabegron Cmax was decreased by 75% (GMR, 25.0% [90% CI, 19.9%-31.3%]) and AUC0-∞ by 51% (48.7% [43.3%-54.7%]) after a low-fat breakfast. Corresponding reductions with the 100-mg dose were 64% (GMR, 36.3% [90% CI, 28.2%-46.8%]) for Cmax and 47% (GMR, 53.2% [90% CI, 46.8%-60.5%]) for AUC0-∞. The fed/fasted ratios for mirabegron Cmax and AUC0-∞ were in general independent of dose or sex. Food delayed Tmax compared with the fasted state, with similar increases with the high- and low-fat meals (0.9 hours with 50 mg and 1.5-2.0 hours with 100 mg). Mirabegron was generally well tolerated, with no apparent difference in AE frequency between the fasted and fed states.

CONCLUSIONS

Mirabegron OCAS tablets exhibited a decrease in mirabegron plasma exposure with food that was independent of dose (50 or 100 mg) or gender but dependent on meal composition. A greater reduction in mirabegron exposure was observed after a low-fat breakfast compared with after a high-fat breakfast. Based on findings from previous studies, the effects of food observed in this study do not warrant dose adjustment in clinical practice. ClinicalTrials.gov identifier: NCT00939757.

A Generic Integrated Physiologically based Whole-body Model of the Glucose-Insulin-Glucagon Regulatory System

Models of glucose metabolism are a valuable tool for fundamental and applied medical research in diabetes. Use cases range from pharmaceutical target selection to automatic blood glucose control. Standard compartmental models represent little biological detail, which hampers the integration of multiscale data and confines predictive capabilities. We developed a detailed, generic physiologically based whole-body model of the glucose-insulin-glucagon regulatory system, reflecting detailed physiological properties of healthy populations and type 1 diabetes individuals expressed in the respective parameterizations. The model features a detailed representation of absorption models for oral glucose, subcutaneous insulin and glucagon, and an insulin receptor model relating pharmacokinetic properties to pharmacodynamic effects. Model development and validation is based on literature data. The quality of predictions is high and captures relevant observed inter- and intra-individual variability. In the generic form, the model can be applied to the development and validation of novel diabetes treatment strategies.

The effect of different meal compositions on the oral bioavailability of treprostinil diolamine in healthy volunteers

WHAT IS KNOWN

Treprostinil diolamine (oral treprostinil) is a prostacyclin analogue currently being evaluated for the treatment of pulmonary arterial hypertension as a sustained-release (SR) oral tablet. Previous data have demonstrated that the oral bioavailability of treprostinil was improved when taken with a meal containing at least 500 calories.

OBJECTIVE

As twice-daily intake of a high-fat, high-calorie meal may be undesirable or not feasible for some patients, this open-label, randomized, crossover study evaluated the effect of different meal compositions [a 500-calorie well-balanced meal (WB500), a 250-calorie well-balanced meal (WB250), a 250-calorie high-fat meal (HF250) and a 250-calorie well-balanced liquid meal (Ensure®)] on the relative bioavailability of oral treprostinil.

METHODS

Thirty-two healthy volunteers were administered a single 1-mg SR tablet of oral treprostinil immediately following each study meal. Each dose of oral treprostinil was separated by a 7-day washout period. Serial plasma samples were obtained over a 36-h postdose. Safety was assessed in all patients who received study drug.

RESULTS AND DISCUSSION

Treprostinil plasma exposure (Cmax and AUC0-inf) decreased only slightly, 5-15% with decreasing caloric and increasing fat content. Headache was the most commonly reported prostacyclin-related adverse event (three reports).

WHAT IS NEW AND CONCLUSION

Overall, there were no clinically significant differences in the relative bioavailability of oral treprostinil when administered immediately after meals containing 250-500 calories and 30-50% fat. These data support the administration of oral treprostinil with a meal containing as few as 250 calories and 30-50% fat, which is significant for ensuring patient convenience and compliance, particularly as consistency with regard to meals may impact oral treprostinil pharmacokinetics.

Apixaban, an oral, direct factor Xa inhibitor: single dose safety, pharmacokinetics, pharmacodynamics and food effect in healthy subjects

Aims

To evaluate apixaban single dose safety, tolerability, pharmacokinetics and pharmacodynamics and assess the effect of food on apixaban pharmacokinetics.

Methods

A double-blind, placebo-controlled, single ascending-dose, first-in-human study assessed apixaban safety, pharmacokinetics and pharmacodynamics in healthy subjects randomized to oral apixaban (n = 43; 0.5–2.5 mg as solution or 5–50 mg as tablets) or placebo (n = 14) under fasted conditions. An open label, randomized, two treatment crossover study investigated apixaban pharmacokinetics/pharmacodynamics in healthy subjects (n = 21) administered apixaban 10 mg in fasted and fed states. Both studies measured apixaban plasma concentration, international normalized ratio (INR), activated partial thromboplastin time (aPTT) and prothrombin time (PT) or a modified PT (mPT).

Results

In the single ascending-dose study increases in apixaban exposure appeared dose-proportional. Median t_max occurred 1.5–3.3 h following oral administration. Mean terminal half-life ranged between 3.6 and 6.8 h following administration of solution doses ≤2.5 mg and between 11.1 and 26.8 h for tablet doses ≥5 mg. Concentration-related changes in pharmacodynamic assessments were observed. After a 50 mg dose, peak aPTT, INR and mPT increased by 1.2-, 1.6- and 2.9-fold, respectively, from baseline. In the food effect study: 90% confidence intervals of geometric mean ratios of apixaban C_max and AUC in a fed vs. fasted state were within the predefined no effect (80–125%) range. Apixaban half-life was approximately 11.5 h. The effect of apixaban on INR, PT and aPTT was comparable following fed and fasted administration.

Conclusions

Single doses of apixaban were well tolerated with a predictable pharmacokinetic/pharmacodynamic profile and a half-life of approximately 12 h. Apixaban can be administered with or without food.

Drug interactions and the pharmacist: focus on everolimus

OBJECTIVE

To evaluate everolimus drug-drug and drug-food interactions, with an emphasis on patients with cancer.

DATA SOURCES

Literature was accessed through PubMed (1990-March 2013) using Boolean combinations of the terms drug interactions, herb-drug interactions, food-drug interactions, everolimus, antineoplastic agents, hormonal, and breast neoplasms. In addition, reference citations from publications and the prescribing information for everolimus were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All articles published in English, including human, animal, and in vitro studies, identified from the data sources were included.

DATA SYNTHESIS

Patients with cancer are at increased risk for drug interactions because of the multiple medications they are prescribed to treat their disease and comorbid conditions. Everolimus, an oral mammalian target of rapamycin (mTOR) inhibitor, is indicated for the treatment in adults with progressive neuroendocrine tumors of pancreatic origin that are unresectable, locally advanced, or metastatic; adults with advanced renal cell carcinoma after failure of treatment with sunitinib or sorafenib; and, recently, postmenopausal women with advanced hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer in combination with exemestane after failure of treatment with letrozole or anastrozole. As its use increases among patients with cancer, clinicians must be knowledgeable about potential drug and/or food/nutrient interactions and the mechanisms by which these interactions occur, to mitigate and prevent unwanted reactions and ensure patient safety.

CONCLUSIONS

Everolimus is a widely used oral mTOR inhibitor that has the potential for drug interactions that may affect therapeutic outcomes, produce toxicities, or both. This article provides a review of evidence-based literature, along with the prescribing information, to educate clinicians on the significance of these drug interactions and their impact on management with everolimus.

Single-Dose Pharmacokinetics of Varenicline, a Selective Nicotinic Receptor Partial Agonist, in Healthy Smokers and Nonsmokers

Varenicline is a novel and selective alpha4beta2 nicotinic receptor partial agonist that is under development for smoking cessation. The primary objectives of this double-blind, placebo-controlled, single-dose, dose-escalation study were to determine the clinical pharmacology of single doses of varenicline in healthy smokers and nonsmokers under fed and fasted conditions and to determine the clinical pharmacology of varenicline administered in the morning and in the evening to smokers. Within each subject group, 4 subjects were randomized to varenicline and 2 subjects to placebo. Subjects received one single oral administration of varenicline or placebo: 6 doses (0.01, 0.03, 0.1, 0.3, 1.0, and 3.0 mg) were investigated in nonsmokers and 7 doses in smokers (0.01, 0.03, 0.1, 0.3, 1.0, 3.0, and 10.0 mg). Varenicline was well tolerated after single doses up to 3.0 mg in smokers and 1.0 mg in nonsmokers. Nausea and vomiting at doses above 3.0 mg in smokers and 1.0 mg in nonsmokers were dose limiting. Systemic exposure to varenicline and pharmacokinetic variability were similar between smokers and nonsmokers. Coadministration with food, smoking restriction, and time-of-day dosing did not affect the pharmacokinetics of varenicline.

Effect of Food, an Antacid, and the H2Antagonist Ranitidine on the Absorption of BAY 59-7939 (Rivaroxaban), an Oral, Direct Factor Xa Inhibitor, in Healthy Subjects

To investigate the influence of food and administration of an antacid (aluminum-magnesium hydroxide) or ranitidine on the absorption of BAY 59-7939 (rivaroxaban), 4 randomized studies were performed in healthy male subjects. In 2 food interaction studies, subjects received BAY 59-7939, either as two 5-mg tablets (fasted and fed), four 5-mg tablets (fasted), or one 20-mg tablet (fasted and fed). In 2 drug interaction studies, BAY 59-7939 (six 5-mg tablets) was given alone or with ranitidine (150 mg twice daily, preceded by a 3-day pretreatment phase) or antacid (10 mL). Plasma samples were obtained to assess pharmacokinetic and pharmacodynamic parameters of BAY 59-7939. In the presence of food, time to maximum concentration (t(max)) was delayed by 1.25 hours; maximum concentration (C(max)) and area under the curve (AUC) were increased, with reduced interindividual variability at higher doses of BAY 59-7939. Compared with baseline, BAY 59-7939 resulted in a relative increase in maximum prothrombin time (PT) prolongation of 44% (10 mg) and 53% (20 mg) in the fasted state, compared with 53% and 83% after food. Time to maximum PT prolongation was delayed by 0.5 to 1.5 hours after food, with no relevant influence of food type. No significant difference in C(max) and AUC was observed with coadministration of BAY 59-7939 and ranitidine or antacid.

Population pharmacokinetics of blonanserin in Chinese healthy volunteers and the effect of the food intake

OBJECTIVE

The aim of the study was to better understand blonanserin population pharmacokinetic (PK) characteristics in Chinese healthy subjects.

METHODS

Data from two studies with 50 subjects were analyzed to investigate the population PK characteristics of blonanserin at single dose (4, 8, and 12 mg) under fasting, multidose (4 mg bid or 8 mg qd for 7 days) and under food intake condition (single dose, 8 mg). Blonanserin plasma concentrations were detected using the high performance liquid chromatography tandem mass spectrometry (LC/MS/MS). A nonlinear mixed-effects model was developed to describe the blonanserin concentration-time profiles.

RESULTS

A two compartment model with first-order absorption was built to describe the time-course of blonanserin. The population-predicted system apparent clearance (CL/F), volume of apparent distribution in center (V(1)/F), and the first-order absorption rate constant (Ka) of blonanserin under fasting was 1230 L/h, 9500 L, and 3.02 h(-1), respectively. Food intake decreased Ka of blonanserin to 0.78 h(-1). The relative bioavailability between fasting and food intake estimated by the final model was 55%. No clinically significant safety issues were identified.

CONCLUSION

This is the first study assessing the PK profile of blonanserin with population PKs method. The results can be used for simulation in further clinical trial and optimize individual dosage regimens using a Bayesian methodology in patients.

Maximum tolerated dose evaluation of the AMPA modulator Org 26576 in healthy volunteers and depressed patients: a summary and method analysis of bridging research in support of phase II dose selection

BACKGROUND

A key challenge to dose selection in early central nervous system (CNS) clinical drug development is that patient tolerability profiles often differ from those of healthy volunteers (HVs), yet HVs are the modal population for determining doses to be investigated in phase II trials. Without clear tolerability data from the target patient population, first efficacy trials may include doses that are either too high or too low, creating undue risk for study participants and the development program overall. Bridging trials address this challenge by carefully investigating safety and tolerability in the target population prior to full-scale proof-of-concept trials.

OBJECTIVE

Org 26576 is an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor positive allosteric modulator that acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. In preparation for phase II efficacy trials in major depressive disorder (MDD), two separate phase I trials were conducted to evaluate safety, tolerability, and pharmacokinetics in HVs and in the target patient population.

METHODS

Both trials were randomized and placebo controlled, and included multiple rising-dose cohorts (HV range 100-400 mg bid; MDD range 100-600 mg bid). HVs (n = 36) and patients with MDD (n = 54) were dosed under similarly controlled conditions in an inpatient facility, HVs for up to 14 days and MDD patients for up to 28 days. Safety, tolerability, and pharmacokinetics were assessed frequently.

RESULTS

Despite comparable pharmacokinetic profiles, the maximum tolerated dose (MTD) in depressed patients was 450 mg bid, twice the MTD established in HVs. No clinically relevant safety issues associated with Org 26576 were noted.

CONCLUSION

This article presents safety, tolerability, and pharmacokinetic data from two different populations examined under similar dosing conditions. The important implications of such bridging work in phase II dose selection are discussed, as are study design and data interpretation challenges.

Case studies for practical food effect assessments across BCS/BDDCS class compounds using in silico, in vitro, and preclinical in vivo data

Practical food effect predictions and assessments were described using in silico, in vitro, and/or in vivo preclinical data to anticipate food effects and Biopharmaceutics Classification System (BCS)/Biopharmaceutics Drug Disposition Classification System (BDDCS) class across drug development stages depending on available data: (1) limited in silico and in vitro data in early discovery; (2) preclinical in vivo pharmacokinetic, absorption, and metabolism data at candidate selection; and (3) physiologically based absorption modeling using biorelevant solubility and precipitation data to quantitatively predict human food effects, oral absorption, and pharmacokinetic profiles for early clinical studies. Early food effect predictions used calculated or measured physicochemical properties to establish a preliminary BCS/BDDCS class. A rat-based preclinical BCS/BDDCS classification used rat in vivo fraction absorbed and metabolism data. Biorelevant solubility and precipitation kinetic data were generated via animal pharmacokinetic studies using advanced compartmental absorption and transit (ACAT) models or in vitro methods. Predicted human plasma concentration-time profiles and the magnitude of the food effects were compared with observed clinical data for assessment of simulation accuracy. Simulations and analyses successfully identified potential food effects across BCS/BDDCS classes 1-4 compounds with an average fold error less than 1.6 in most cases. ACAT physiological absorption models accurately predicted positive food effects in human for poorly soluble bases after oral dosage forms. Integration of solubility, precipitation time, and metabolism data allowed confident identification of a compound's BCS/BDDCS class, its likely food effects, along with prediction of human exposure profiles under fast and fed conditions.

Understanding pharmacokinetic food effects using molecular dynamics simulation coupled with physiologically based pharmacokinetic modeling

In this study, a molecular dynamics (MD) method is assessed as a new front-end tool for deriving relevant drug-micelle partitioning rates for use in conjunction with a compartmental-style gastrointestinal absorption model. A refined mechanistic approach for handling micelle-associated vs unbound drug is presented and examined in terms of its utility for projecting human oral pharmacokinetic food/formulation effects. Similar to predecessor oral absorption models, the intestinal drug absorption rate is formulated as a function of the combined permeability through the unstirred water layer and the epithelial membrane, however, an additional diffusion coefficient adjustment is applied to account for the viscosity changes of the postprandial small intestine. Bulk passage of drug particles through the GI tract is simulated by compartmental transit through a network of nine compartments comprising the stomach, small intestine and colon. The tandem MD simulation/compartmental absorption algorithm is applied to identify factors influencing the fed vs fasted absorption ratios of a structurally diverse set of orally administered drugs. The data illustrate the interplay and apparent compromise between micelle solubilization and permeability.

Therapeutic drug monitoring of posaconazole in patients with acute myeloid leukemia or myelodysplastic syndrome

Posaconazole is a broad-spectrum triazole antifungal available as an oral suspension. Pharmacokinetic data showed a high variability of plasma posaconazole concentrations (PPCs) in patients, suggesting a potential interest in drug monitoring. The aim of our prospective study was to measure the PPCs in prophylactically treated patients to evaluate the impact of different factors on these concentrations. In 40 patients treated prophylactically with posaconazole for acute myeloid leukemia or myelodysplastic syndrome between February 2009 and August 2010, PPCs were measured at day 7 of treatment and then twice weekly. Demographic data, clinical data (including gastrointestinal disorders, comedications, and treatment compliance), caloric and fat intake, and biological data were collected and evaluated. We obtained 275 measurements of PPCs, with a median of 430 ng/ml. PPCs were significantly lower in patients with mucositis (P < 0.001), nausea (P = 0.03), diarrhea (P = 0.03), or vomiting (P = 0.05). PPCs were higher in patients with a higher caloric intake (P = 0.02), while the proportion of fat intake had no influence on PPCs (P = 0.84). The concomitant use of proton pump inhibitors decreased the PPCs (P = 0.02), while the use of tacrolimus increased the PPC (P = 0.03). In the multivariate analysis, the factors influencing the PPCs independently were the concomitant use of tacrolimus (P < 0.001), the presence of mucositis (P = 0.01), and food intake (P = 0.02). Our study confirmed the high variability of posaconazole bioavailability and showed the significant influence of gastrointestinal disorders, food intake, and concomitant medication on the PPCs. However, the optimal PPCs still remain to be defined and correlated with clinical efficacy.

Single-dose pharmacokinetics of lenalidomide in healthy volunteers: dose proportionality, food effect, and racial sensitivity

PURPOSE

Lenalidomide is an immunomodulatory drug with efficacy in various hematological malignancies. The purpose of these studies was to evaluate the single-dose pharmacokinetics of lenalidomide, including dose proportionality, food effect, and racial sensitivity.

METHODS

Three studies were conducted including a total of 58 healthy subjects: a randomized, single-blind, alternating group, single-ascending dose study; a randomized, two-way crossover food effect study; and a randomized, double-blind, two-group, within-subject, single-ascending dose study.

RESULTS

Oral absorption of lenalidomide was rapid and the maximum plasma concentration (C (max)) was observed approximately 1 h post-dose. Co-administration with a high-fat meal reduced the area under the concentration-time curve (AUC) and C (max) by approximately 20 and 50 %, respectively, and delayed time to C (max) (t (max)) by 1.63 h. However, phase III trials were dosed without regard to food; therefore, clinical relevance of the food effect was minimal. The terminal elimination half-life (t (½)) was 3-4 h at doses up to 50 mg and was not affected by food. The AUC and C (max) were proportional to lenalidomide single doses (5-400 mg), and total and renal clearance were dose-independent. The R- to S-lenalidomide ratio in plasma was stable over time, approximately 45-55 % of total drug. There were no differences in pharmacokinetic parameters, dose-exposure relationship, or enantiomeric ratio, between Japanese and Caucasian subjects.

CONCLUSION

Lenalidomide displayed linear pharmacokinetics from doses 5-400 mg in healthy subjects. Although food reduced bioavailability, this was not considered clinically relevant. Lenalidomide was generally well tolerated in both ethnic groups.

Mechanisms underlying food-drug interactions: inhibition of intestinal metabolism and transport

Food-drug interaction studies are critical to evaluate appropriate dosing, timing, and formulation of new drug candidates. These interactions often reflect prandial-associated changes in the extent and/or rate of systemic drug exposure. Physiologic and physicochemical mechanisms underlying food effects on drug disposition are well-characterized. However, biochemical mechanisms involving drug metabolizing enzymes and transport proteins remain underexplored. Several plant-derived beverages have been shown to modulate enzymes and transporters in the intestine, leading to altered pharmacokinetic (PK) and potentially negative pharmacodynamic (PD) outcomes. Commonly consumed fruit juices, teas, and alcoholic drinks contain phytochemicals that inhibit intestinal cytochrome P450 and phase II conjugation enzymes, as well as uptake and efflux transport proteins. Whereas myriad phytochemicals have been shown to inhibit these processes in vitro, translation to the clinic has been deemed insignificant or undetermined. An overlooked prerequisite for elucidating food effects on drug PK is thorough knowledge of causative bioactive ingredients. Substantial variability in bioactive ingredient composition and activity of a given dietary substance poses a challenge in conducting robust food-drug interaction studies. This confounding factor can be addressed by identifying and characterizing specific components, which could be used as marker compounds to improve clinical trial design and quantitatively predict food effects. Interpretation and integration of data from in vitro, in vivo, and in silico studies require collaborative expertise from multiple disciplines, from botany to clinical pharmacology (i.e., plant to patient). Development of more systematic methods and guidelines is needed to address the general lack of information on examining drug-dietary substance interactions prospectively.

Challenges and opportunities in achieving bioequivalence for fixed-dose combination products

Fixed-dose combination (FDC) products are becoming a popular treatment option because of increased patient compliance and convenience, improved clinical effectiveness, and reduced cost to the patient, among several other reasons. A commonly applied approach for approval of a FDC product is demonstrating bioequivalence between the FDC and co-administration of individual mono-products, provided that there is adequate safety and efficacy data for co-administration of the individual agents. However, achieving bioequivalence between the FDC and individual mono-products can be very challenging, and sometimes not possible since combining multiple active ingredients, especially insoluble molecules, in a single drug product could complicate its biopharmaceutical and pharmacokinetic behavior. In this review, some of the major challenges often encountered while assessing bioequivalence during FDC development will be presented along with discussion of future opportunities to facilitate FDC development and approval.

Physicochemical characterization of a prodrug of a radionuclide decorporation agent for oral delivery

Intravenously administered calcium and zinc complexes of diethylenetriaminepentaacetic acid (DTPA) are the agents of choice to treat individuals who have been contaminated with radioactive actinides. However, their use in a mass casualty scenario is hampered by the need for trained personnel to receive treatment. Because DTPA is a highly ionized molecule with permeability-limited bioavailability, the penta-ethyl ester prodrug of DTPA is under evaluation as an orally bioavailable radionuclide decorporation agent. In this work, the physicochemical properties of DTPA penta-ethyl ester were characterized to assess its potential for oral delivery. DTPA penta-ethyl ester was determined to be a low-viscosity liquid with Newtonian flow characteristics. Consistent with the measured pK(a) values, which range from 2.93 to 10.87, this prodrug exhibits pH-dependent solubility and lipophilicity properties that are representative of a weak base and favorable for oral absorption. It is miscible in solvents that are nonpolar to moderately polar and is sufficiently stable to avoid premature hydrolysis during gastrointestinal transit. Therapeutic effects were demonstrated in an initial efficacy study wherein oral treatments of the prodrug were given to rats contaminated with ²⁴¹Am, providing preliminary indications of successful oral delivery. The properties of the prodrug indicate that it is conducive to oral delivery and may offer therapeutic benefits over the standard DTPA therapy following radionuclide contamination.

Predicting the oral absorption of a poorly soluble, poorly permeable weak base using biorelevant dissolution and transfer model tests coupled with a physiologically based pharmacokinetic model

For predicting food effects and simulating plasma profiles of poorly soluble drugs, physiologically based pharmacokinetic models have become a widely accepted tool in academia and the pharmaceutical industry. Up till now, however, simulations appearing in the open literature have mainly focused on BCS class II compounds, and many of these simulations tend to have more of a "retrospective" than a prognostic, predictive character. In this work, investigations on the absorption of a weakly basic BCS class IV drug, "Compound A", were performed. The objective was to predict the plasma profiles of an immediate release (IR) formulation of Compound A in the fasted and fed state. For this purpose, in vitro biorelevant dissolution tests and transfer model experiments were conducted. Dissolution and precipitation kinetics were then combined with in vivo post-absorptive disposition parameters using STELLA® software. As Compound A not only exhibits poor solubility but also poor permeability, a previously developed STELLA® model was revised to accommodate the less than optimal permeability characteristics as well as precipitation of the drug in the fasted state small intestine. Permeability restrictions were introduced into the model using an absorption rate constant calculated from the Caco-2 permeability value of Compound A, the effective intestinal surface area and appropriate intestinal fluid volumes. The results show that biorelevant dissolution tests are a helpful tool to predict food effects of Compound A qualitatively. However, the plasma profiles of Compound A could only be predicted quantitatively when the results of biorelevant dissolution test were coupled with the newly developed PBPK model.