Pharmacokinetics of maropitant citrate after oral administration of multiple doses in adult horses.

The neurokinin-1 (NK-1) receptor antagonist, maropitant citrate, mitigates nausea and vomiting in dogs and cats. Nausea is poorly understood in horses, and clinical use of NK-1 receptor antagonists has not been reported. This study aimed to determine the pharmacokinetics and safety of maropitant after administration of multiple doses. We hypothesized that maropitant concentrations would be similar at steady state to those reported in dogs, with minimal adverse effects. Maropitant was administered at 4 mg/kg orally, once daily for 5 days in seven adult horses. Serial plasma maropitant concentrations were measured by liquid chromatography-mass spectrometry. Noncompartmental pharmacokinetic parameters were determined. The maximum, minimum, and average concentrations of maropitant achieved at steady state were 375.5 ± 200, 16.8 ± 7.7, and 73.5 ± 45.1 ng/ml, respectively. The terminal elimination half-life was 11.6 ± 1.4 hr, and the accumulation index was 1.3 ± 0.07. Heart rate decreased between Day 1 and Day 5 (p = .005), with three horses having heart rates of 20 beats per minute and atrioventricular block on Day 5. Pharmacokinetics of repeated maropitant administration suggests the drug could be considered for use in healthy horses. Further investigation on the clinical relevancy of its cardiac effects is warranted.

Population Pharmacokinetic Analysis of Fluticasone Furoate/Umeclidinium Bromide/Vilanterol in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: Population pharmacokinetic methods were used to characterize the pharmacokinetics of fluticasone furoate (FF), umeclidinium (UMEC), and vilanterol (VI) in patients with chronic obstructive pulmonary disease (COPD) when administered as a fixed-dose combination via a single closed inhaler. METHODS: Plasma concentration data from three studies were analyzed using non-linear mixed-effects modeling in NONMEM®. RESULTS: The pooled dataset consisted of 2948, 2589, and 3331 FF, UMEC, and VI observations from 714, 622, and 817 patients with COPD, respectively. There were 41%, 13%, and 21% of observations below the quantification limit for FF, UMEC, and VI, respectively. The pharmacokinetics of FF, UMEC, and VI were all adequately described by a two-compartment model with first-order absorption. The following covariates were statistically significant, but none were considered to be clinically relevant. For FF, Japanese heritage and FF/VI treatment on apparent inhaled clearance (CL/F) with FF CL/F 35% lower in patients of Japanese heritage across all treatments and FF CL/F 42% higher in patients with COPD following FF/VI administration. This is in line with the product label. For UMEC, weight, age, and smoking status on CL/F and weight on apparent volume of distribution (V2/F) with every 10% increase in age from 60 years of age leading to approximately a 6% decrease in UMEC CL/F and every 10% increase in weight from 70 kg leading to approximately a 6% increase in UMEC CL/F and approximately an 8% increase in UMEC V2/F. For a subject with COPD who smoked, UMEC CL/F was 28% higher. For VI, weight on CL/F and smoking status on V2/F with an approximately 4% increase in VI CL/F for every 10% increase in weight from 70 kg, and for a subject with COPD who smoked, VI V2/F was 46% higher. The majority of these covariates have been previously identified in historical analyses. None of these effects were clinically relevant in terms of systemic exposures and do not warrant dose adjustment. CONCLUSIONS: All FF, UMEC, and VI plasma concentrations were well interspersed with historical data and were all adequately described by a two-compartment model with first-order absorption. There were no clinically relevant differences in FF, UMEC, or VI systemic exposures when administered as FF/UMEC/VI, FF/VI + UMEC, or the dual combinations FF/VI and/or UMEC/VI.

Pharmacokinetic profile and safety of intravenous NEPA, a fixed combination of fosnetupitant and palonosetron, in cancer patients: Prevention of chemotherapy-induced nausea and vomiting associated with highly emetogenic chemotherapy.

NEPA is the fixed combination antiemetic composed of the neurokinin-1 receptor antagonist netupitant and the 5-hydroxytryptamine-3 receptor antagonist palonosetron. The intravenous (i.v.) formulation of NEPA (fosnetupitant 235 mg/palonosetron 0.25 mg) was developed to enhance the convenience of NEPA administration. In a phase 3 study, i.v. NEPA showed acceptable safety with low risk for injection-site reactions. This study evaluated the pharmacokinetics and safety of i.v. NEPA in cancer patients. This was a single-center, single-dose phase 1 study in patients receiving highly emetogenic chemotherapy. Patients received a 30-min infusion of i.v. NEPA plus oral dexamethasone (12 mg) prior to chemotherapy, and oral dexamethasone (8 mg/daily) on days 2-4. Twenty-four patients received the complete i.v. NEPA infusion volume. Fosnetupitant maximum plasma concentration (Cmax) was reached at the end of infusion and decreased to <1% of Cmax 30 min later. Netupitant was rapidly released from its prodrug and Cmax of 590 ng/ml was reached at the end of fosnetupitant infusion, with a mean exposure (AUC∞) of 15,588 h∙ng/ml. Palonosetron Cmax was reached at the end of infusion, with a mean AUC∞ of 36.07 h∙ng/ml. The most common adverse events were constipation (29%), nausea (17%), and vasospasm (8%). No i.v. NEPA-related injection site reactions occurred. Fosnetupitant conversion to netupitant occurred rapidly in cancer patients. Netupitant and palonosetron pharmacokinetic profiles in i.v. NEPA were similar to those reported for oral NEPA. i.v. NEPA was well tolerated with a similar safety profile to oral NEPA. i.v. NEPA provides additional administration convenience. Clinical trial registration number: EudraCT 2015-004750-18.

Blood eosinophils and treatment response with triple and dual combination therapy in chronic obstructive pulmonary disease: analysis of the IMPACT trial.

BACKGROUND: Previous studies have highlighted a relationship between reduction in rate of exacerbations with therapies containing inhaled corticosteroids (ICS) and baseline blood eosinophil count in patients with chronic obstructive pulmonary disease (COPD). The IMPACT trial showed that once-daily single-inhaler triple therapy significantly reduced exacerbations versus dual therapies. Blood eosinophil counts and smoking status could be important modifiers of treatment response to ICS. We aimed to model these relationships and their interactions, including outcomes other than exacerbations. METHODS: IMPACT was a phase 3, randomised, double-blind, parallel-group, 52-week global study comparing once-daily single-inhaler triple therapy (fluticasone furoate-umeclidinium-vilanterol) with dual inhaled therapy (fluticasone furoate-vilanterol or umeclidinium-vilanterol). Eligible patients had moderate-to-very-severe COPD and at least one moderate or severe exacerbation in the previous year. We used fractional polynomials to model continuous blood eosinophil counts. We used negative binomial regression for numbers of moderate and severe exacerbations, severe exacerbations, and pneumonia. We modelled differences at week 52 in trough FEV1, St George's Respiratory Questionnaire (SGRQ) total score, and Transition Dyspnoea Index using repeated measurements mixed effect models. IMPACT was registered with ClinicalTrials.gov, number NCT02164513. FINDINGS: The magnitude of benefit of regimens containing ICS (fluticasone furoate-umeclidinium-vilanterol n=4151 and fluticasone furoate-vilanterol n=4134) in reducing rates of moderate and severe exacerbations increased in proportion with blood eosinophil count, compared with a non-ICS dual long-acting bronchodilator (umeclidinium-vilanterol n=2070). The moderate and severe exacerbation rate ratio for triple therapy versus umeclidinium-vilanterol was 0·88 (95% CI 0·74 to 1·04) at blood eosinophil count less than 90 cells per µL and 0·56 (0·47 to 0·66) at counts of 310 cells per µL or more; the corresponding rate ratio for fluticasone furoate-vilanterol versus umeclidinium-vilanterol was 1·09 (0·91 to 1·29) and 0·56 (0·47 to 0·66), respectively. Similar results were observed for FEV1, Transition Dyspnoea Index, and SGRQ total score; however, the relationship with FEV1 was less marked. At blood eosinophil counts less than 90 cells per µL and at counts of 310 cells per µL or more, the triple therapy versus umeclidinium-vilanterol treatment difference was 40 mL (95% CI 10 to 70) and 60 mL (20 to 100) for trough FEV1, -0·01 (-0·68 to 0·66) and 0·30 (-0·37 to 0·97) for Transition Dyspnoea Index score, and -0·01 (-1·81 to 1·78) and -2·78 (-4·64 to -0·92) for SGRQ total score, respectively. Smoking status modified the relationship between observed efficacy and blood eosinophil count for moderate or severe exacerbations, Transition Dyspnoea Index, and FEV1, with former smokers being more corticosteroid responsive at any eosinophil count than current smokers. INTERPRETATION: This analysis of the IMPACT trial shows that assessment of blood eosinophil count and smoking status has the potential to optimise ICS use in clinical practice in patients with COPD and a history of exacerbations. FUNDING: GlaxoSmithKline.

Pharmacokinetics of single doses of maropitant citrate in adult horses.

The neurokinin-1 (NK) receptor antagonist, maropitant citrate, mitigates nausea and vomiting in dogs and cats. Nausea is poorly understood and likely under-recognized in horses. Use of NK-1 receptor antagonists in horses has not been reported. The purpose of this study was to determine the pharmacokinetic profile of maropitant in seven adult horses after single intravenous (IV; 1 mg/kg) and intragastric (IG; 2 mg/kg) doses. A randomized, crossover design was performed. Serial blood samples were collected after dosing; maropitant concentrations were measured using LC-MS/MS. Pharmacokinetic parameters were determined using noncompartmental analysis. The mean plasma maropitant concentration 3 min after IV administration was 800 ± 140 ng/ml, elimination half-life was 10.37 ± 2.07 h, and volume of distribution was 6.54 ± 1.84 L/kg. The maximum concentration following IG administration was 80 ± 40 ng/ml, and elimination half-life was 9.64 ± 1.27 hr. Oral bioavailability was variable at 13.3 ± 5.3%. Maropitant concentrations achieved after IG administration were comparable to those in small animals. Concentrations after IV administration were lower than in dogs and cats. Elimination half-life was longer than in dogs and shorter than in cats. This study is the basis for further investigations into using maropitant in horses.

A phase 2a randomized controlled study to evaluate the pharmacokinetic, safety, tolerability and clinical effect of topically applied Umeclidinium in subjects with primary axillary hyperhidrosis.

BACKGROUND: Hyperhidrosis is a common medical condition which can have a significant impact on quality of life. Umeclidinium (UMEC) is a long-acting muscarinic antagonist (LAMA) developed as a dermal formulation. OBJECTIVES: This 2-week, double-blind, randomized, vehicle-controlled study evaluated systemic exposure, safety and tolerability of topically administered UMEC in subjects with primary axillary hyperhidrosis. Clinical effect was a secondary objective, measured by gravimetry and the hyperhidrosis disease severity scale (HDSS). Vehicle was included to evaluate safety. METHODS: Twenty-three subjects were randomized to either 1.85% UMEC (N = 18) or vehicle (N = 5) once daily. RESULTS: Measurable plasma concentrations were observed in 78% of subjects after the treatment. Nine subjects (50%) on UMEC and two subjects (40%) on vehicle reported AEs, most commonly application site reactions. At Day 15, seven subjects (41%) in UMEC and two subjects (40%) in vehicle had at least a 50% reduction in sweat production. Eight subjects (47%) in UMEC and one subject (20%) in vehicle had at least a two-point reduction in HDSS. No comparisons of treatment arms were planned prospectively. CONCLUSIONS: The measurable exposure, acceptable safety and preliminary clinical activity observed in this proof-of-concept study suggest the potential clinical utility of topical UMEC in subjects with axillary hyperhidrosis.

Preclinical abuse liability assessment of ABT-126, an agonist at the α7 nicotinic acetylcholine receptor (nAChR).

ABT-126 is a nicotinic acetylcholine receptor (nAChR) agonist that is selective for the α7 subtype of the receptor. nAChRs are thought to play a role in a variety of neurocognitive processes and have been a pharmacologic target for disorders with cognitive impairment, including schizophrenia and Alzheimer's disease. As part of the preclinical safety package for ABT-126, its potential for abuse was assessed. While the involvement of the α4ß2 subtype of the nicotinic receptor in the addictive properties of nicotine has been demonstrated, the role of the α7 receptor has been studied much less extensively. A number of preclinical assays of abuse potential including open-field, drug discrimination and self-administration were employed in male rats. ABT-126 had modest effects on locomotor activity in the open-field assay. In nicotine and d-amphetamine drug discrimination assays, ABT-126 administration failed to produce appreciable d-amphetamine-like or nicotine-like responding, suggesting that its interoceptive effects are distinct from those of these drugs of abuse. In rats trained to self-administer cocaine, substitution with ABT-126 was similar to substitution with saline, indicating that it lacks reinforcing effects. No evidence of physical dependence was noted following subchronic administration. Overall, these data suggest that ABT-126 has a low potential for abuse. Together with other literature on this drug class, it appears that drugs that selectively activate α7 nAChRs are not likely to result in abuse or dependence.

Population Pharmacokinetics Modeling of Inhaled Umeclidinium for Adult Patients with Asthma.

BACKGROUND: Umeclidinium (UMEC; a long-acting anti-muscarinic) in combination with fluticasone furoate (an inhaled corticosteroid) is in development for asthma treatment. This secondary analysis aimed to develop a population pharmacokinetic model characterizing UMEC in adults with asthma, and evaluated the impact of covariates on pharmacokinetic parameters. METHODS: Plasma concentration data from study NCT01641692 (assessing once-daily UMEC 15.6, 31.25, 62.5, 125, and 250 mcg, twice daily UMEC 15.6 and 31.25 mcg, and placebo) were analyzed using non-linear mixed-effect modeling in NONMEM®. Full likelihood, including observed data and data below the quantification limit (treated as censored), was maximized. Study endpoints were population pharmacokinetics (including apparent inhaled clearance [CL/F] and apparent distribution volume in the central compartment [V c/F]) and derived pharmacokinetic parameters (area under the concentration-time curve [AUC] and maximum concentration [C max] at steady-state). RESULTS: In total, 128 patients provided 3757 data points. The pharmacokinetics of UMEC were best described using a two-compartment model with intravenous bolus input, due to fast absorption following inhalation. CL/F was 257 L/h and V c/F was 804 L. Creatinine clearance was a significant covariate for CL/F, as were age and body weight for V c/F. AUC and C max increased with increasing UMEC dose (once-daily 15.6-250 mcg: AUC0-24 median: 64.7-863 pg h/mL; C max median: 10.6-256 pg/mL). CONCLUSION: The final population pharmacokinetic model adequately described the data, demonstrating minimal creatinine clearance, age, and body weight effects on overall plasma UMEC pharmacokinetics and systemic exposure.

Synthesis and Pharmacological Evaluation of [11C]Granisetron and [18F]Fluoropalonosetron as PET Probes for 5-HT3 Receptor Imaging.

Serotonin-gated ionotropic 5-HT3 receptors are the major pharmacological targets for antiemetic compounds. Furthermore, they have become a focus for the treatment of irritable bowel syndrome (IBS) and there is some evidence that pharmacological modulation of 5-HT3 receptors might alleviate symptoms of other neurological disorders. Highly selective, high-affinity antagonists, such as granisetron (Kytril) and palonosetron (Aloxi), belong to a family of drugs (the "setrons") that are well established for clinical use. To enable us to better understand the actions of these drugs in vivo, we report the synthesis of 8-fluoropalonosetron (15) that has a binding affinity (Ki = 0.26 ± 0.05 nM) similar to the parent drug (Ki = 0.21 ± 0.03 nM). We radiolabeled 15 by nucleophilic 18F-fluorination of an unsymmetrical diaryliodonium palonosetron precursor and achieved the radiosynthesis of 1-(methyl-11C)-N-granisetron ([11C]2) through N-alkylation with [11C]CH3I, respectively. Both compounds [18F]15 (chemical and radiochemical purity >95%, specific activity 41 GBq/µmol) and [11C]2 (chemical and radiochemical purity ≥99%, specific activity 170 GBq/µmol) were evaluated for their utility as positron emission tomography (PET) probes. Using mouse and rat brain slices, in vitro autoradiography with both [18F]15 and [11C]2 revealed a heterogeneous and displaceable binding in cortical and hippocampal regions that are known to express 5-HT3 receptors at significant levels. Subsequent PET experiments suggested that [18F]15 and [11C]2 are of limited utility for the PET imaging of brain 5-HT3 receptors in vivo.

Development and validation of a rapid LC-MS/MS method for simultaneous determination of netupitant and palonosetron in human plasma and its application to a pharmacokinetic study.

A simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was firstly developed and validated for simultaneous determination of netupitant and palonosetron in human plasma using ibrutinib as the internal standard (IS). Following liquid-liquid extraction, the compounds were eluted isocratically on a Phenomenex C18 column (50mm×2.0mm, 3µm) with the mobile phase consisting of acetonitrile and 10mM ammonium acetate buffer (pH 9.0) (89:11, v/v) at the flow rate of 0.3mL/min. The monitored ion transitions were m/z 579.5→522.4 for netupitant, m/z 297.3→110.2 for palonosetron and m/z 441.2→138.1 for IS. Chromatographic run time was 2.5min per injection, which made it possible to analyze more than 300 of samples per day. The assay exhibited a linear dynamic range of 5-1000ng/mL for netupitant and 0.02-10ng/mL for palonosetron in plasma. The values for both within- and between-day precision and accuracy were well within the generally accepted criteria for analytical methods (<15%). Selectivity, linearity, lower limit of quantification (LLOQ), accuracy, precision, stability, matrix effect, recovery and carry-over effect were evaluated for all analytes. The method is simple, rapid, and has been applied successfully to a pharmacokinetic study of netupitant and palonosetron in healthy volunteers.

A Novel Method for Studying the Pharmacokinetics of [(14) C]Umeclidinium After Application to the Axilla or Palm of Healthy Male Subjects.

Umeclidinium (UMEC), a long-acting muscarinic antagonist approved for chronic obstructive pulmonary disease (COPD), was investigated for primary hyperhidrosis as topical therapy. This study evaluated the pharmacokinetics, safety, and tolerability of a single dose of [(14) C]UMEC applied to either unoccluded axilla (UA), occluded axilla (OA), or occluded palm (OP) of healthy males. After 8 h the formulation was removed. [(14) C]UMEC plasma concentrations (Cp) were quantified by accelerator mass spectrometry. Occlusion increased systemic exposure by 3.8-fold. Due to UMEC absorption-limited pharmacokinetics, Cp data from the OA were combined with intravenous data from a phase I study. The data were described by a two-compartment population model with sequential zero and first-order absorption and linear elimination. Simulated systemic exposure following q.d. doses to axilla was similar to the exposure from the inhaled therapy, suggesting that systemic safety following dermal administration can be bridged to the inhaled program, and offering the potential for a reduced number of studies and/or subjects.

Concentration-QT analysis of the randomized, placebo- and moxifloxacin-controlled thorough QT study of umeclidinium monotherapy and umeclidinium/vilanterol combination in healthy subjects.

The long-acting muscarinic antagonist umeclidinium (UMEC) is approved as a once-daily monotherapy and in combination with the long-acting ß2 agonist vilanterol (VI) for chronic obstructive pulmonary disease. The objective of this analysis was to assess the relationship between observed plasma UMEC and/or VI concentrations and QT interval corrected using Fridericia's correction (QTcF). 103 subjects were enrolled and 86 (83 %) completed the study. Subjects were randomized to 4 of 5 repeat-dose treatments (days 1-10: n = 77 subjects received placebo, n = 76 UMEC 500 µg, n = 78 UMEC/VI 125/25 µg, or n = 76 UMEC/VI 500/100 µg; day 10: n = 74 oral tablet moxifloxacin 400 mg [positive control]). The concentration-QTcF interval relationship was examined using nonlinear mixed-effects methods. For UMEC, predicted QTcF interval prolongation (at observed geometric mean of maximum plasma concentrations) was -2.38 ms (90 % prediction interval [PI] -3.82, -0.85) with UMEC 500 µg and -0.50 ms (90 % PI -0.80, -0.18) and -2.01 ms (90 % PI -3.22, -0.72) with UMEC/VI 125/25 µg and 500/100 µg, respectively. For VI, estimates were 5.89 ms (90 % PI 4.89, 6.91) and 7.23 ms (90 % PI 5.88, 8.55) with UMEC/VI 125/25 µg and 500/100 µg, respectively. Combined additive mean effects were estimated for UMEC/VI 125/25 µg (5.39 ms [90 % PI 4.40, 6.47]) and 500/100 µg (5.22 ms [90 % PI 3.72, 6.80]). The model-predicted decrease with UMEC and increase with UMEC/VI combination in QTcF interval suggest that the QT effect is likely attributable to VI. These model-predicted results support those of previously-published traditional statistical analyses.

Development and validation of an improved HPLC-MS/MS method for comparative pharmacokinetics of penehyclidine hydrochloride following a single intravenous or intramuscular injection.

Penehyclidine hydrochloride (PHC) is an anticholinergic drug with both antimuscarinic and antinicotinic activity. In order to compare the pharmacokinetics of two administration routes (intravenous injection (i.v.) and intramuscular injection (i.m.)) of PHC, an improved High Performance Liquid Chromatography Tandem Mass Spectrometry (HPLC-MS/MS) bioanalytical method was developed for the quantification of PHC in plasma and urine using verapamil as the internal standard (I.S.). Chromatography was performed using a Thermo Hypersil GOLD column (30mm×2.1mm, 3µm), with a gradient elution of 1‰ formic acid-10mmol/L ammonium acetate and acetonitrile at 0.3mL/min. Detection and quantitation were performed by electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ion mode. The most intense [M+H](+) MRM transition of PHC at m/z 316.2→128.3 was used for PHC quantitation, and the transition at m/z 454.6→303.2 was used to monitor I.S. The lower limit of quantification (LLOQ) was 0.05 ng/mL. The intraday precision was <6.71% and the interday precision was <11.69%. The pharmacokinetic parameters of i.v. and i.m. administration routes were as follows (i.v. vs i.m.): t1/2 15.73 vs 17.24h, Tmax 0.06 vs 0.26h, AUC0-t 69.35 vs 67.90hng/mL, AUC0-inf 78.24 vs 79.67hng/mL, Cmax 37.5 vs 9.1ng/mL, Ae0-24h 22.7 vs 25.21µg. There were no significant differences between parameters t1/2 and AUC (P>0.05), but significant differences were observed in Cmax, Tmax and Ae0-24h between the two administration routes (P<0.05). The mean absolute bioavailability of the i.m. administration route was 98.4% (95% confidence interval, 93.4-103.6%). Safety results showed that PHC appeared to be well tolerated in both i.v. and i.m. administration routes and pharmacokinetic results showed that PHC was nearly completely absorbed via i.m. administration route.

Evaluation of the effect of food and age on the pharmacokinetics of oral netupitant and palonosetron in healthy subjects: A randomized, open-label, crossover phase 1 study.

Antiemetic treatment compliance is important to prevent chemotherapy-induced nausea and vomiting, a feared chemotherapy side effect. NEPA, a new oral fixed combination of netupitant, a highly selective NK1 receptor antagonist (RA), and palonosetron, a second-generation 5-HT3 RA, targets dual antiemetic pathways with a single dose. This study investigated the effect of food intake and age on NEPA pharmacokinetics (PK) and safety. In this open-label, single-center, randomized, phase 1 study, 24 adults (18-45 years) received NEPA in a fed or fasted state during the first treatment period and in the alternative state in the next treatment period. Twelve elderly subjects (≥65 years) received NEPA in a fasted state. Blood samples were taken for netupitant and palonosetron PK analysis. In the fed condition, netupitant plasma exposure increased, whereas palonosetron PK parameters were not affected. Furthermore, elderly subjects showed increased netupitant and palonosetron exposure compared with adults. All adverse events were mild/moderate, with constipation and headache the most common. Although food intake and age altered NEPA PK, dose adjustments were not needed, as netupitant and palonosetron exposure increases did not lead to safety concerns in healthy subjects.

Theoretical evaluation of antiemetic effects of 5-HT3 receptor antagonists for prevention of vomiting induced by cisplatin.

5-HT(3) receptor antagonists are widely used as antiemetic agents in clinical setting, of which palonosetron, with a long elimination half life (t(1/2)), has recently become available. It is important to evaluate the concentration of serotonin when investigating the antiemetic effects of 5-HT(3) receptor antagonists, as those effects are not based solely on the t(1/2) value. We theoretically evaluated the antiemetic effects of three 5-HT(3) receptor antagonists (granisetron, azasetron, palonosetron) on cisplatin-induced nausea and vomiting by estimating the time course of the 5-HT(3) receptor occupancy of serotonin. We estimated the 5-HT(3) receptor occupancy of serotonin in the small intestine, based on the time course of plasma concentration of each 5-HT(3) receptor antagonist and the time course of concentration of serotonin near the 5-HT(3) receptor in the small intestine after administration of cisplatin. The antiemetic effect of each 5-HT(3) receptor antagonist was evaluated based on the normal level of 5-HT(3) receptor occupancy of serotonin. Our results suggest that an adequate antiemetic effect will be provided when a dose of 75 mg/m(2) of cisplatin is given to patients along with any single administration of granisetron, azasetron, or palonosetron at a usual dose. On the other hand, the 5-HT(3) receptor occupancy of serotonin was found to be significantly lower than normal for several days after administration of palonosetron, as compared to granisetron and azasetron, indicating that constipation may be induced. Our results show that granisetron, azasetron, and palonosetron each have an adequate antiemetic effect after administration of 75 mg/m(2) of cisplatin.

Combining benefits of an adrenergic and a muscarinic blocker in a single formulation - a pharmacokinetic evaluation.

A pharmacokinetic bioequivalence study was conducted in Asian subjects, to compare a fixed dose combination capsule single oral dose of alpha adrenoceptor blocker-Alfuzosin hydrochloride 10mg extended release and muscarinic antagonists-Solifenacin succinate 5mg against individually administered Xatral XL 10mg tablets (Alfuzosin) of Sanofi Synthelabo Limited, United Kingdom (UK) and Vesicare 5mg tablets (Solifenacin) of Astellas Pharma Limited, UK under fed conditions. Blood samples were collected pre-dose up to 72 h post dose for determination of plasma Alfuzosin and Solifenacin concentrations and calculation of the pharmacokinetic parameters. ANOVA was performed on the log (natural)-transformed pharmacokinetic parameters. A 90% confidence interval for the ratios of the test and reference product averages (least square means) were calculated for alfuzosin and solifenacin. The 90% confidence intervals obtained for alfuzosin for Cmax, AUC0-t and AUC0-∞ were 102.74-122.75%, 95.84-116.96% and 95.82-116.76%, respectively. The 90% confidence intervals obtained for Solifenacin for Cmax, and AUC0-72 were 89.55-97.91% and 90.47-99.38%, respectively. Based on the results, the fixed dose combination was concluded to be bioequivalent to individually administered products.

Effect of verapamil on systemic exposure and safety of umeclidinium and vilanterol: a randomized and open-label study.

BACKGROUND: The combination of umeclidinium (UMEC), a long-acting muscarinic receptor antagonist, and vilanterol (VI), a selective long-acting ß2 agonist, is in development for the treatment of chronic obstructive pulmonary disease (COPD). This study evaluated the pharmacokinetics, safety and tolerability, and pharmacodynamics of once-daily, inhaled UMEC and UMEC/VI when co-administered with oral verapamil, a moderate P-glycoprotein transporter and moderate cytochrome P450 3A4 (CYP3A4) inhibitor frequently used by patients with COPD and cardiovascular comorbidities. METHODS: Subjects were randomized to one of two 13-day treatment regimens: UMEC 500 µg or UMEC 500 µg/VI 25 µg. All subjects received a single tablet containing 240 mg verapamil on each of days 9-13. RESULTS: Repeat doses of UMEC and UMEC/VI in combination with and without verapamil were safe and well tolerated. There was no increase in systemic exposure of UMEC when administered in combination with VI compared to UMEC alone. UMEC maximum concentration was similar with or without verapamil; a moderate increase in UMEC area under the curve (approximately 1.4-fold) was observed with verapamil. Verapamil did not increase systemic exposure to VI following administration of the UMEC/VI combination. CONCLUSION: Administration of UMEC and UMEC/VI combination was well tolerated and did not show clinically relevant increases in systemic exposure for either drug. The UMEC/VI combination is unlikely to have a clinically meaningful drug-drug interaction with moderate P-glycoprotein transporter and CYP3A4 inhibitor drugs.

Species-dependent metabolism of a novel selective α7 neuronal acetylcholine receptor agonist ABT-107.

Metabolism of ABT-107 was investigated in in vitro hepatic systems, in rat and monkey receiving [¹4C]ABT-107, and in vivo plasma in rat, dog, monkey and human. In in vitro hepatic systems, ABT-107 was primarily cleared via oxidative metabolism, and proceeded via two parallel pathways. Pathway 1, ABT-107 was oxidized at the nitrogen of quinuclidine moiety to form M1. Pathway 2, oxidation occurred at indole-containing moiety to form M2. Metabolism via N-oxidation was predominant in dog and rat, while in monkey and human, metabolism proceeded primarily via oxidation of indole-containing moiety. ABT-107 was extensively metabolized in vivo in rat and monkey. M1 was primarily found in rat urine and bile; whereas, M2 was the major metabolite in monkey urine and feces. M1 was the predominant circulating metabolite in dog and rat. M2 was the primary circulating metabolite in monkey and human. Enzymatic studies suggested M1 formation was primarily mediated by renal FMO1. CYP3A4, 1A2, 2J2 and 2D6 were primary enzymes catalyzing M2 formation. Biotransformation of ABT-107 in human and monkey is markedly different from that in dog and rat, suggesting that monkey is an appropriate model for predicting human biotransformation and toxicology of ABT-107.

Local and systemic effects of inhaled AZD9164 compared with tiotropium in patients with COPD.

There is still a need for new agents which improve upon the therapeutic index of tiotropium, the current standard of care for many patients with chronic obstructive pulmonary disease (COPD). We examined in patients with COPD the efficacy of single doses of AZD9164, an M(3)-selective muscarinic antagonist, to identify an appropriate dose-range for future studies. COPD patients (n = 28) inhaled AZD9164 (100, 400 and 1200 µg), tiotropium (18 µg) and placebo at 5 study centre visits (Clinicaltrials.gov identifier NCT00939211). The effects of these test drugs on average (E(av)), peak (E(max)) and trough (E(22-26)) forced expiratory volume in one second (FEV(1)) were assessed, as were systemically-mediated effects and the safety and exposure of single doses of AZD9164. AZD9164 100, 400 and 1200 µg caused increases in FEV(1) to peak effects of 12, 17 and 12% above baseline respectively, following an initial transient and dose-related fall in FEV(1) and associated increase in mild respiratory symptoms such as cough. Bronchodilation was maintained overnight, with minimal FEV(1) decline. AZD9164 400 and 1200 µg produced larger effects than tiotropium on E(22-26) (p < 0.05; both doses) while AZD9164 400 µg also had larger effects on E(max) (p = 0.001) and E(av) (p < 0.05). There were no serious adverse events and statistically significant systemic effects were observed only with AZD9164 1200 µg. AZD9164 may improve upon the therapeutic index of tiotropium, increasing the magnitude and duration of lung function improvements without increasing systemically-mediated adverse events. The initial bronchoconstrictor effect of AZD9164 requires further investigation.

The pharmacokinetics of maropitant citrate dosed orally to dogs at 2 mg/kg and 8 mg/kg once daily for 14 days consecutive days.

The pharmacokinetics of maropitant were evaluated in beagle dogs dosed orally with Cerenia® tablets (Pfizer Animal Health) once daily for 14 consecutive days at either 2 mg/kg or 8 mg/kg bodyweight. Noncompartmental pharmacokinetic analysis was performed on the plasma concentration data to measure the AUC(0-24) (after first and last doses), Ct (trough concentration-measured 24 h after each dose), Cmax (after first and last doses), tmax (after first and last doses), λz (terminal disposition rate constant; after last dose), t(1/2) (after last dose), and CL/F (oral clearance; after last dose). Maropitant accumulation in plasma was substantially greater after fourteen daily 8 mg/kg doses than after fourteen daily 2 mg/kg doses as reflected in the AUC(0-24) accumulation ratio of 4.81 at 8 mg/kg and 2.46 at 2 mg/kg. This is most likely due to previously identified nonlinear pharmacokinetics of maropitant in which high doses (8 mg/kg) saturate the metabolic clearance mechanisms and delay drug elimination. To determine the time to reach steady-state maropitant plasma levels, a nonlinear model was fit to the least squares (LS) means maropitant Ct values for each treatment group. Based on this model, 90% of steady-state was determined to occur at approximately four doses for daily 2 mg/kg oral dosing and eight doses for daily 8 mg/kg oral dosing.