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Wilson disease (WD) is an autosomal recessive inherited disorder of copper metabolism. Chelation of excessive copper is recommended but data on the pharmacokinetics of trientine are limited. The aim of this study was to compare the pharmacokinetics of a new trientine tetrahydrochloride formulation (TETA 4HCl) with those of an established trientine dihydrochloride (TETA 2HCl) salt. A randomised single-centre crossover study to evaluate the pharmacokinetics, safety and tolerability of two different oral formulations of trientine (TETA 4HCl tablets vs TETA 2HCl capsules) in 23 healthy adult subjects receiving a single dose equivalent to 600 mg of trientine base was performed. Following oral administration, the median time to reach maximum plasma concentration (Tmax) was 2.00 h (TETA 4HCl) and 3.00 h (TETA 2HCl). The rate (maximum plasma concentration [Cmax]) and extent (area under the plasma concentration-time curve from time zero to infinity [AUC0–∞]) of absorption of the active moiety, trientine, were greater (by approximately 68% and 56%, respectively) for TETA 4HCl than for the TETA 2HCl formulation. The two formulations presented a similar terminal elimination rate (λz) and a similar terminal half-life (t½) for trientine. Differences between TETA 4HCl and TETA 2HCl in the levels of the two main mono- and diacetylated metabolites were less than seen for trientine. For both tested formulations, healthy male volunteers demonstrated higher trientine plasma levels but lower mono- and diacetylated metabolite levels compared with females, with no sex differences in terminal half-life (t½) observed. Single oral doses of both formulations were safe and well tolerated. Compared with an identical dose of a TETA 2HCl formulation, the TETA 4HCl formulation provided more rapid absorption of trientine and greater systemic exposure in healthy subjects. Clinical Trials Number EudraCT # 2015-002199-25.

Introduction This randomized, double-blind, placebo-controlled study in healthy volunteers assessed the safety, tolerability, and pharmacokinetics of single ascending doses of intravenously administered NX210-a linear peptide derived from subcommissural organ-spondin-and explored the effects on blood/urine biomarkers and cerebral activity. Methods Participants in five cohorts (n = 8 each) were randomized to receive a single intravenous dose of NX210 (n = 6 each) (0.4, 1.25, 2.5, 5, and 10 mg/kg) or placebo (n = 2 each); in total, 10 and 29 participants received placebo and NX210, respectively. Blood samples were collected for pharmacokinetics within 180 min post dosing. Plasma and urine were collected from participants (cohorts: 2.5, 5, and 10 mg/kg) for biomarker analysis and electroencephalography (EEG) recordings within 48 h post dosing. Safety/tolerability and pharmacokinetic data were assessed before ascending to the next dose. Results The study included 39 participants. All dosages were safe and well tolerated. All treatment-emergent adverse events (n = 17) were of mild severity and resolved spontaneously (except one with unknown outcome). Twelve treatment-emergent adverse events (70.6%) were deemed drug related; seven of those (58.3%) concerned nervous system disorders (dizziness, headache, and somnolence). The pharmacokinetic analysis indicated a short half-life in plasma (6-20 min), high apparent volume of distribution (1870-4120 L), and rapid clearance (7440-16,400 L/h). In plasma, tryptophan and homocysteine showed dose-related increase and decrease, respectively. No drug dose effect was found for the glutamate or glutamine plasma biomarkers. Nevertheless, decreased blood glutamate and increased glutamine were observed in participants treated with NX210 versus placebo. EEG showed a statistically significant decrease in beta and gamma bands and a dose-dependent increasing trend in alpha bands. Pharmacodynamics effects were sustained for several hours (plasma) or 48 h (urine and EEG). Conclusion NX210 is safe and well tolerated and may exert beneficial effects on the central nervous system, particularly in terms of cognitive processing.

In vitro studies have indicated that the P2Y12 receptor antagonist selatogrel is a substrate of organic anion-transporting-polypeptide (OATP)1B1 and OATP1B3 that are known to mediate hepatic uptake. Selatogrel is primarily eliminated via the biliary route. Therefore, the study aim was to investigate the effect of rifampin-mediated OATP1B1 and OATP1B3 inhibition on the pharmacokinetics (PK) of selatogrel. This was a randomized, double-blind, placebo-controlled, two-period, crossover study in 14 healthy subjects. In each period, a single subcutaneous dose of 4 mg selatogrel was administered, either immediately after a single intravenous 30 minutes infusion of 600 mg rifampin or after placebo. Plasma samples were collected for 36 hours and analyzed using a validated liquid chromatography-tandem mass spectrometry method. PK parameters of selatogrel were calculated using noncompartmental analysis. The effect of rifampin was explored based on geometric mean peak plasma concentration (Cmax ) and area under the concentration curve from zero to infinity (AUC0-∞ ) ratios and for time of maximum plasma concentration (Tmax ) by Wilcoxon signed rank test. In addition, the safety and tolerability of the study treatments were evaluated. The geometric mean ratios of Cmax and AUC0-∞ were 1.19 (90% confidence interval (CI) 1.11-1.28) and 1.43 (90% CI 1.36-1.51), respectively, indicating a minor selatogrel exposure increase when administered after an infusion of rifampin compared with placebo. Rifampin administration did not affect terminal half-life (t½ ) or Tmax of selatogrel. All study treatments were safe and well-tolerated. A single dose of 600 mg rifampin, a potent OATP1B1/1B3 inhibitor, did not impact the PK of selatogrel to a clinically relevant extent suggesting that OATP1B1 and OATP1B3 transporters do not play a major role in the elimination of selatogrel.

Glenzocimab (ACT017) is a humanized monoclonal antigen‐binding fragment (Fab) directed against the human platelet glycoprotein VI, a key receptor for collagen and fibrin that plays a major role in thrombus growth and stability. Glenzocimab is being developed as an antiplatelet agent to treat the acute phase of ischemic stroke. During a phase I study in healthy volunteers, the population pharmacokinetics (PK) and pharmacodynamics (PD) of glenzocimab were modeled using Monolix software. The PK/PD model thus described glenzocimab plasma concentrations and its effects on ex vivo collagen‐induced platelet aggregation. Glenzocimab was found to have dose‐proportional, 2‐compartmental PK with a central distribution volume of 4.1 L, and first and second half‐lives of 0.84 and 9.6 hours. Interindividual variability in clearance in healthy volunteers was mainly explained by its dependence on body weight. The glenzocimab effect was described using an immediate effect model with a dose‐dependent half maximal inhibitory concentration: Larger doses resulted in a stronger effect at the same glenzocimab plasma concentration. The mechanism of the overproportional concentration effect at higher doses remained unexplained. PK/PD simulations predicted that 1000‐mg glenzocimab given as a 6‐hour infusion reduced platelet aggregation to 20% in 100% of subjects at 6 hours and in 60% of subjects at 12 hours after dosing. Simulations revealed a limited impact of creatinine clearance on exposure, suggesting that no dose adjustments were required with respect to renal function. Future studies in patients with ischemic stroke are now needed to establish the relationship between ex vivo platelet aggregation and the clinical effect.

Objective— ACT017 is a novel, first in class, therapeutic antibody to platelet GPVI (glycoprotein VI) with potent and selective antiplatelet effects. This first-in-human, randomized, placebo-controlled phase 1 study was conducted to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of ACT017 in healthy subjects. Approach and Results— Six cohorts of 8 healthy male and female subjects each received ascending single doses of ACT017 (n=6) or placebo (n=2) as a 6-hour intravenous infusion, with ¼ of the total dose administered within 15 minutes and the rest of the dose (¾ of the total dose) administered within 5 hours and 45 minutes. The 6 investigated doses ranged from 62.5 to 2000 mg. All doses of ACT017 were well tolerated, and no serious adverse events occurred during the study. None of the subjects reported an infusion site reaction. Template bleeding time was not affected in a clinically significant manner by any of the ACT017 doses. Plasma concentrations, determined by liquid chromatography-tandem mass spectrometry, increased linearly with the dose received as were the established pharmacokinetics values. There was no change in the platelet count, platelet GPVI expression assessed by flow cytometry, or plasma levels of soluble GPVI assessed by ELISA. In contrast, administration of ACT017 inhibited collagen-induced platelet aggregation measured by light transmission aggregometry on platelet-rich plasma, and the extent and duration of the effect were dose-dependent. Conclusions— The novel antiplatelet agent ACT017 has consistent pharmacokinetic/pharmacodynamic properties and favorable safety and tolerability profiles warranting further clinical development.

To assess the absolute bioavailability of 20 mEq magnesium lactate extended-release (ER) caplets and to assess the effect of food on the pharmacokinetics of these ER caplets.Magnesium in different salt forms is available as over-the-counter oral formulations. The absorption and bioavailability is highly affected by the water solubility of the salt form. A new ER caplet of 10 mEq strength of magnesium L-lactate dihydrate has been developed to increase the bioavailability of magnesium.An open label, single-dose, randomized, three-period, cross-over study in healthy adults was conducted with three treatments: (a) single oral dose of 20 mEq magnesium L-lactate dehydrate under fasting conditions, (b) single intravenous (IV) infusion of 20 mEq magnesium sulfate, and (c) single oral dose of 20 mEq magnesium L-lactate dehydrate under fed conditions. Urine and blood samples were collected for analysis of urinary and serum magnesium concentrations.Absolute bioavailabilities of the caplets under fasted and fed conditions, compared to IV magnesium sulfate, were 20.26% (fasted) and 12.49% (fed) in serum, based on the geometric mean ratio (GMR) of the baseline-adjusted AUCThis new magnesium formulation has reasonable bioavailability and might be a valuable addition to the currently available magnesium oral products.

Peter Dogterom,1 Robert Riesenberg,2 Rik de Greef,1 Justin Dennie,3 Martin Johnson,1 Venkatesh Pilla Reddy,1 André MM Miltenburg,1 Robert L Findling,4 Abhijeet Jakate,5 Timothy J Carrothers,5 Matthew D Troyer3 1Early Stage Development, Merck Sharp and Dohme, Oss, the Netherlands; 2Atlanta Center for Medical Research, Atlanta, GA, 3Merck, Kenilworth, NJ, 4Kennedy Krieger Institute, Johns Hopkins University, Baltimore, MD, 5Allergan, Madison, NJ, USA Purpose: This study aimed to characterize the pharmacokinetic (PK) properties, safety, and tolerability of asenapine, and to develop a population PK model in pediatric patients with schizophrenia, bipolar disorder, or other psychiatric disorders. Methods: Two Phase I multiple ascending-dose studies were conducted to evaluate the PK, safety, and tolerability of sublingual asenapine in pediatric patients (age 10–17 years) with schizophrenia or bipolar I disorder. Patients received asenapine 1–10 mg twice daily for up to 12 days. PK parameters (maximum concentration [Cmax], area under the curve from 0 to 12 hours [AUC0–12], time to Cmax [Tmax], and half-life) were summarized for asenapine with descriptive statistics, and safety parameters were collected. A population PK model, which included the two Phase I studies and two additional Phase III efficacy studies (asenapine 2.5–10 mg twice daily for up to 8 weeks, age 10–17 years), was developed using nonlinear mixed-effect modeling based on a previously developed adult PK model. The final model was used in simulations to obtain asenapine-exposure estimates across pediatric subgroups and to determine if intrinsic covariates warrant dose adjustments. Results: The PK of asenapine showed rapid absorption (Tmax ~1 hour) with an apparent terminal half-life between 16 and 32 hours. Increases in mean Cmax and AUC0–12 appeared to be dose-proportional in one study and near dose-proportional in the second study. Steady state was attained within 8 days. The most frequently occurring treatment-emergent adverse events were dysgeusia, sedation, and oral hypoesthesia. Simulation-based estimates of Cmax and AUC0–12 were similar for pediatric and adult patients; age, body-mass index, race, and sex were not associated with changes in asenapine exposure. Conclusion: Asenapine was generally safe and well tolerated in pediatric patients aged 10–17 years. PK and safety data were similar to that observed in the adult population. Intrinsic factors had no significant impact on asenapine exposure, indicating there is no need for dose adjustments in the pediatric population. Keywords: asenapine, pharmacokinetics, schizophrenia, bipolar disorder, child and adolescent, atypical antipsychotic

Posaconazole in oral suspension must be taken multiple times a day with food (preferably a high-fat meal) to ensure adequate exposure among patients. We evaluated the effect of food on the bioavailability of a new delayed-release tablet formulation of posaconazole at the proposed clinical dose of 300 mg once daily in a randomized, open-label, single-dose, two-period crossover study with 18 healthy volunteers. When a single 300-mg dose of posaconazole in tablet form (3 tablets × 100 mg) was administered with a high-fat meal, the posaconazole area under the concentration-time curve from 0 to 72 h (AUC 0–72 ) and maximum concentration in plasma ( C max ) increased 51% and 16%, respectively, compared to those after administration in the fasted state. The median time to C max ( T max ) shifted from 5 h in the fasted state to 6 h under fed conditions. No serious adverse events were reported, and no subject discontinued the study due to an adverse event. Six of the 18 subjects reported at least one clinical adverse event; all of these events were mild and short lasting. The results of this study demonstrate that a high-fat meal only modestly increases the mean posaconazole exposure (AUC), ∼1.5-fold, after administration of posaconazole tablets, in contrast to the 4-fold increase in AUC observed previously for a posaconazole oral suspension given with a high-fat meal.

This double-blind, placebo-controlled, randomized study is the first in healthy volunteers to describe the safety, tolerability, and pharmacokinetics of sublingual asenapine at therapeutic dosages. After a 2-day placebo run-in phase, healthy male volunteers received placebo or asenapine escalated to dosages of 3, 5, 10, or 15 mg bid. Another group received single doses (2 and 5 mg) 1 week apart. Serial blood samples were obtained for pharmacokinetic analysis. The single asenapine doses and multiple bid doses up to 10 mg were well tolerated. The most frequent treatment-emergent adverse events were somnolence, oral paresthesia, fatigue, headache, dizziness, and dyspnea. Clinically relevant abnormalities or trends in laboratory and vital signs measures, physical examinations, or electrocardiograms were not observed. Asenapine was rapidly absorbed, with a tmax of ∼1 hour, and was biphasically eliminated with a terminal elimination half-life of 20 to 30 hours. In the range of 3 to 10 mg bid, increases in plasma concentrations were less than dose proportional. Asenapine appears to be well tolerated at single doses up to 5 mg and multiple doses up to 10 mg bid and can be administered to healthy volunteers in clinical pharmacology studies using the dosing regimens described.

Asenapine is indicated for treatment of schizophrenia in the United States and acute treatment of manic or mixed episodes, as monotherapy (United States and European Union) or adjunct therapy (United States only), associated with bipolar I disorder. It is extensively metabolized; the 2 main metabolites are asenapine N-glucuronide and N-desmethyl-asenapine. The authors investigated the pharmacokinetic interactions between asenapine and valproate in an open-label, randomized, 2-way crossover study. Twenty-four healthy male volunteers received sublingual doses of asenapine 5 mg alone or under steady-state valproate (500 mg bid for 9 days). Blood samples collected until 72 hours postdosing were analyzed for asenapine, N-desmethyl-asenapine, and asenapine N-glucuronide. Compared with asenapine alone, valproate substantially reduced N-glucuronide formation (area under the curve from 0 to infinity [AUC(0-∞)] reduced 7.4-fold, maximum concentration [C(max)] reduced 6.6-fold) and moderately reduced N-desmethyl-asenapine formation (AUC(0-∞) reduced 30%, C(max) unchanged). Coadministration of valproate did not affect asenapine AUC(0-∞) and C(max) (confidence intervals for the ratios of asenapine AUC(0-∞) and C(max) were contained within the predefined 0.80-1.25 acceptance range). Low-dose valproate, although almost completely inhibiting glucuronidation of asenapine, did not affect the pharmacokinetics of asenapine itself, the entity primarily responsible for the pharmacologic effects of the drug.

Background and Objective: The effects of hepatic or renal impairment on the pharmacokinetics of atypical antipsychotics are not well understood. Drug exposure may increase in patients with hepatic disease, owing to a reduction of certain metabolic enzymes. The objective of the present study was to study the effects of hepatic or renal impairment on the pharmacokinetics of asenapine and its N-desmethyl and N +-glucuronide metabolites. Methods: Two clinical studies were performed to assess exposure to asenapine, desmethylasenapine and asenapine N +-glucuronide in subjects with hepatic or renal impairment. Pharmacokinetic parameters were determined from plasma concentration-time data, using standard noncompartmental methods. The pharmacokinetic variables that were studied included the maximum plasma concentration (Cmax) and the time to reach the maximum plasma concentration (tmax). Eligible subjects, from inpatient and outpatient clinics, were aged ≥18 years with a body mass index of ≥18kg/m2 and ≤32kg/m2. Sublingual asenapine (Saphris®) was administered as a single 5 mg dose. Results: Thirty subjects participated in the hepatic impairment study (normal hepatic function, n = 8; mild hepatic impairment [Child-Pugh class A], n = 8; moderate hepatic impairment [Child-Pugh class B], n = 8; severe hepatic impairment [Child-Pugh class C], n = 6). Thirty-three subjects were enrolled in the renal impairment study (normal renal function, n = 9; mild renal impairment, n=8; moderate renal impairment, n = 8; severe renal impairment, n = 8). Asenapine and N-desmethylasenapine exposures were unaltered in subjects with mild or moderate hepatic impairment, compared with healthy controls. Severe hepatic impairment was associated with increased area under the plasma concentration-time curve from time zero to infinity (AUC∞) values for total asenapine, N-desmethylasenapine and asenapine N +-glucuronide (5-, 3-, and 2-fold, respectively), with slight increases in the Cmax of asenapine but 3- and 2-fold decreases in the Cmax values for N-desmethylasenapine and asenapine N +-glucuronide, respectively, compared with healthy controls. The mean AUC∞ of unbound asenapine was more than 7-fold higher in subjects with severe hepatic impairment than in healthy controls. Mild renal impairment was associated with slight elevations in the AUC∞ of asenapine compared with healthy controls; alterations observed with moderate and severe renal impairment were marginal. N-desmethylasenapine exposure was only slightly altered by renal impairment. No correlations were observed between exposure and creatinine clearance. Conclusion: Severe hepatic impairment (Child-Pugh class C) was associated with pronounced increases in asenapine exposure, but significant increases were not seen with mild (Child-Pugh class A) or moderate (Child-Pugh class B) hepatic impairment, or with any degree of renal impairment. Asenapine is not recommended in patients with severe hepatic impairment; no dose adjustment is needed in patients with mild or moderate hepatic impairment, or in patients with renal impairment.

The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor potentiator Org 26576 represents an interesting pharmacological tool to evaluate the utility of glutamatergic enhancement towards the treatment of psychiatric disorders. In this study, a rat-human translational pharmacokinetic-pharmacodynamic (PK-PD) model of AMPA receptor modulation was used to predict human target engagement and inform dose selection in efficacy clinical trials.Modelling and simulation was applied to rat plasma and cerebrospinal fluid (CSF) pharmacokinetic and pharmacodynamic measurements to identify a target concentration (EC(80)) for AMPA receptor modulation. Human plasma pharmacokinetics was determined from 33 healthy volunteers and eight major depressive disorder patients. From four out of these eight patients, CSF PK was also determined. Simulations of human CSF levels were performed for several doses of Org 26576.Org 26576 (0.1-10 mg/kg, i.v.) potentiated rat hippocampal AMPA receptor responses in an exposure-dependant manner. The rat plasma and CSF PK data were fitted by one-compartment model each. The rat CSF PK-PD model yielded an EC(80) value of 593 ng/ml (90% confidence interval 406.8, 1,264.1). The human plasma and CSF PK data were simultaneously well described by a two-compartment model. Simulations showed that in humans at 100 mg QD, CSF levels of Org 26576 would exceed the EC(80) target concentration for about 2 h and that 400 mg BID would engage AMPA receptors for 24 h.The modelling approach provided useful insight on the likely human dose-molecular target engagement relationship for Org 26576. Based on the current analysis, 100 and 400 mg BID would be suitable to provide 'phasic' and 'continuous' AMPA receptor engagement, respectively.

Objective: To investigate the effects of rifampin on the steady-state pharmacokinetics of gepirone and metabo- lites after multiple dosing of both drugs. Methods: 24 subjects completed a randomized crossover study with 2 study phases separated by a washout period of at least 4 weeks. The subjects received multiple dosing of gepirone extended-release (gepirone ER) (20 mg daily for 2 days titrated to 40 mg daily for 5 days) with and without concurrent use of rifampin 600 mg daily. Plasma concentrations of gepirone and two principal metabolites were determined for up to 48 hours after dosing on day 7. Urinary 6 - hydroxycortisol:cortisol ratio was also used to assess the extent of enzyme induction during both study periods. Results: Rifampin significantly decreased the area under the plasma concentration-time curves (AUC) of gepirone and 3´-OH-gepirone by 95% and 65%, respectively. The peak concentration (Cmax) values also were reduced by 92% and 58%, respectively. On the other hand, there were minimal changes in AUC and Cmax of 1-PP during concurrent use of rifampin. Gepirone dosing did not change the urinary 6 -hydroxycortisol:cortisol ratio, in contrast to a 4.1-fold increase in the ratio with concurrent use of rifampin. Conclusions: Rifampin significantly decreased the systemic exposure of gepirone and 3´-OH-gepirone. The likely mecha- nism is induction of CYP3A4-mediated first-pass metabolism in the intestine and the liver. Concurrent use of potent CYP3A4 enzyme inducers might lead to significant reduction in pharmacologic effect of gepirone. On the other hand, gepirone does not appear to have CYP3A4 induction or inhibition effects.

Two pharmacokinetic studies were performed to investigate whether there is any interaction between etonogestrel or ethinylestradiol released from the combined contraceptive vaginal ring NuvaRing and concomitant treatment with orally administered amoxicillin or doxycycline.In one study, healthy women were randomised to receive either NuvaRing alone for 21 days or NuvaRing for 21 days plus amoxicillin on days 1-10. After a 7-day ring-free washout period, women were crossed over to the alternate regimen for a further 21-day treatment period. The other study used an identical design except that women received doxycycline instead of amoxicillin. The amoxicillin study measured serum etonogestrel and ethinylestradiol levels and area under the serum concentration-time curve (AUC) values over the initial 12 hours on days 1 (AUC(12)) and 10 (AUC(216-228)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)). The doxycycline study measured AUC values over the initial 24 hours on days 1 (AUC(24)) and 10 (AUC(216-240)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)).No differences in etonogestrel or ethinylestradiol serum concentrations were observed between subjects using NuvaRing alone versus those receiving the ring plus either of the antibiotics. Calculation of etonogestrel and ethinylestradiol interaction/control ratios confirmed the absence of pharmacokinetic interactions.The results from these studies demonstrate the absence of pharmacokinetic interactions between etonogestrel and ethinylestradiol released from NuvaRing and the oral antibiotics amoxicillin and doxycycline, suggesting that contraceptive efficacy would also be unaffected.

To support the evaluation of the pharmacokinetic parameters of asenapine (ASE) in urine, we developed and validated online solid-phase extraction high-performance liquid chromatography methods with tandem mass spectrometry detection (SPE-LC-MS/MS) for the quantification of ASE and two of its major metabolites, N-desmethylasenapine (DMA) and asenapine-N⁺-glucuronide (ASG). The linearity in human urine was found acceptable for quantification in a concentration range of 0.500-100 ng/mL for ASE and DMA and 10.0-3000 ng/mL for ASG, respectively.

To determine the effects of food on the pharmacokinetics of sublingual asenapine. Healthy male volunteers (n = 26, age 19–53 years) randomly received a single sublingual dose of asenapine 5 mg after ≥10 h fasting (Treatment A, reference), after a high-fat meal (Treatment B) and after ≥10 h fasting with a high-fat meal at 4 h post-dose (Treatment C). Blood samples were drawn over 72 h to measure asenapine plasma concentrations. Effects of food intake on asenapine pharmacokinetics were assessed using bioequivalence criteria and evaluated using a compartmental modelling analysis. Compared with the reference, mean asenapine exposure (AUC0-last and AUC0-∞) was approximately 20 % lower after intake of a high-fat meal prior to dosing, whereas Cmax decreased by only about 10 %. When a high-fat meal was taken 4 h post-dose in the fasting state, asenapine concentrations were similar to the reference during the first 4 h post-dose. After the meal intake, asenapine concentrations decreased quickly for several hours. Compartmental modelling indicated that a transient 2.5-fold increase in asenapine clearance after eating could explain the asenapine concentration–time profiles for both food regimens. To our knowledge, this is the first study investigating the effect of food upon the sublingual administration of a drug. A high-fat meal taken before or 4 h post-dose of sublingual asenapine indirectly caused a transient increase in liver blood flow that resulted in a temporal increase in asenapine clearance. As the effects on asenapine exposure were small and not clinically relevant, no additional restrictions are required for the timing of food intake in relation to asenapine dosing.

Org 26576 acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. The aim of this Phase 1b study ( N=54) was to explore safety, tolerability, pharmacokinetics, and pharmacodynamics of Org 26576 in depressed patients. Part I ( N=24) evaluated the maximum tolerated dose (MTD) and optimal titration schedule in a multiple rising dose paradigm (range 100 mg BID to 600 mg BID); Part II ( N=30) utilized a parallel groups design (100 mg BID, 400 mg BID, placebo) to examine all endpoints over a 28-day dosing period. Based on the number of moderate intensity adverse events reported at the 600 mg BID dose level, the MTD established in Part I was 450 mg BID. Symptomatic improvement as measured by the Montgomery-Asberg Depression Rating Scale was numerically greater in the Org 26576 groups than in the placebo group in both study parts. In Part II, the 400 mg BID dose was associated with improvements in executive functioning and speed of processing cognitive tests. Org 26576 was also associated with growth hormone increases and cortisol decreases at the end of treatment but did not influence prolactin or brain-derived neurotrophic factor. The quantitative electroencephalogram index Antidepressant Treatment Response at Week 1 was able to significantly predict symptomatic response at endpoint in the active treatment group, as was early improvement in social acuity. Overall, Org 26576 demonstrated good tolerability and pharmacokinetic properties in depressed patients, and pharmacodynamic endpoints suggested that it may show promise in future well-controlled, adequately powered proof of concept trials.

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 100–600mg 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.

To support the evaluation of the pharmacokinetic parameters of asenapine (ASE) in urine, we developed and validated online solid-phase extraction high-performance liquid chromatography methods with tandem mass spectrometry detection (SPE-LC-MS/MS) for the quantification of ASE and two of its major metabolites, N-desmethylasenapine (DMA) and asenapine-N⁺-glucuronide (ASG). The linearity in human urine was found acceptable for quantification in a concentration range of 0.500-100 ng/mL for ASE and DMA and 10.0-3000 ng/mL for ASG, respectively.

The development and validation of methods for determining concentrations of the antipsychotic drug asenapine (ASE) and three of its metabolites [N-desmethylasenapine (DMA), asenapine-N+-glucuronide (ASG) and 11-O-sulfate-asenapine (OSA)] in human plasma using LC-MS/MS with automated solid-phase extraction is described. The three assessment methods in human plasma were found to be acceptable for quantification in the ranges 0.0250–20.0 ng/mL (ASE), 0.0500–20.0 ng/mL (DMA and OSA) and 0.250–50.0 ng/mL (ASG). Copyright © 2011 John Wiley & Sons, Ltd.

Standard toxicological studies in dogs using high doses of vasodilators and positive inotropic/vasodilating agents give rise to a species-specific cardiotoxicity. The reason may be the extreme sensitivity of the dog to the pharmacological effects of these drugs; exaggerated pharmacodynamic effects and prolonged disturbance of homeostasis mechanisms often are responsible for the observed organ lesions. An assessment of the toxicological relevance and the risk for patients taking the drugs at therapeutic doses cannot be made without taking into account their pathomechanisms and the pathophysiological basis of the exceptional reaction patterns occurring in dogs. A large series of vasodilating and positive inotropic agents are presented, their pharmacological properties are described, and toxicological effects in dogs are compared. In view of the poor correlation between the distinct cardiac lesions induced in dogs and a lack of comparable toxicity in humans, it appears desirable to reassess the adequacy of the standard toxicological approaches for these substances.

The secretion of very-low-density lipoprotein from hepatocytes proceeds through the microtubules. In this study, the role of glutathione in the maintenance of intact microtubules and the secretion of very-low-density lipoprotein has been investigated. When rat hepatocytes were incubated with reagents that deplete glutathione (e.g., diethylmaleate, α-bromoisovalerylurea or allyl alcohol) or reacted directly with protein thiols (disulfiram), the secretion of very-low-density lipoprotein by the cells was inhibited and the microtubules were severely damaged as visualized by immunofluorescence staining. Both events occurred within 30 min; long before, an effect on the energy status of the cells became evident. The observed inhibition of the secretion therefore seems due to an effect of the toxicants on the microtubules. For α-bromoisovalerylurea, diethylmaleic acid and allyl alcohol, it may be related to glutathione depletion; preincubation of the hepatocytes with N-acetyl-L-cysteine reduced the decrease of glutathione by α-bromoisovalerylurea and allyl alcohol (but not of diethylmaleic acid) and almost completely prevented the inhibition of very-low-density lipoprotein secretion and microtubule damage. Depletion of glutathione may result in modification of a small group of essential free protein thiols. Disulfiram did not deplete glutathione, and N-acetyl-L-cysteine could not prevent the effects of disulfiram on microtubules. The binding to protein thiols of radiolabeled disulfiram, which binds to microtubules in vitro, was determined. At 0.2 mmol/L disulfiram, only 3% of total cellular protein thiols were conjugated, but secretion of very-low-density lipoprotein was already inhibited by 25%, and microtubules were severely affected. We propose that modification of a small fraction of cellular protein thiols results in the loss of microtubular ultrastructure and thereby leads to inhibition of very-low-density lipoprotein secretion. (HEPATOLOGY 1991;14:1259–1268.)

Hepatocytes have been isolated from normal and vitamin E-deficient rats in which the hepatic vitamin E level was less than 6% that of controls. The hypothesis was tested that extracellular calcium ameliorates chemical-induced cell killing because it decreases the extent of vitamin E loss induced by oxidative stress: such a retarding effect of calcium on cytotoxicity should be lost in hepatocytes from vitamin E-deficients rats. In normal hepatocytes, allyl alcohol and ethacrynic acid induced oxidative stress as indicated by GSH depletion, lipid peroxidation and cell death. Extracellular calcium retarded the induction of lipid peroxidation and cell death without affecting the GSH depletion. In vitamin E-deficient cells, extracellular calcium had lost its protective effect on ethacrynic acid- and allyl-alcohol induced cytotoxicity; it did not affect the GSH depletion and subsequent induction of lipid peroxidation and cell death by ethacrynic acid. However, in vitamin E-deficient hepatocytes, extracellular calcium even potentiated the cytotoxicity of allyl alcohol; under those conditions it also increased GSH loss. Neither in normal, nor in vitamin E-deficient hepatocytes, extracellular calcium had an effect on disulfiram-induced cytotoxicity, i.e. cell death in the absence of lipid peroxidation. These results support the hypothesis that the protecting effect of extracellular calcium on cytotoxicity, associated with lipid peroxidation in normal hepatocytes, is mediated by its protection against intracellular vitamin E loss.

Two studies were performed to investigate whether ethinylestradiol (EE) and etonogestrel (ENG) released from NuvaRing (NR) are affected by concomitant treatment with the antibiotics amoxicillin (A) and doxycycline (D). Sixteen healthy women per study (age: 18 to 40 yrs.) were randomised to 21 days of treatment with NuvaRing, either alone (control) or concomitantly with amoxicillin (875 mg twice daily for 10 days, study I) or doxycycline (100 mg once daily for 10 days, study II). After a 7-days washout they were crossed over to the alternate treatment. Based on serum EE and ENG levels, area under the curve (AUC) values over 12 hours (amoxicillin) or 24 hours (doxycycline) on days 1 and 10 and for the whole of days 1-11 and days 1–22 were calculated and tested for interactions based on FDA guidance. Geometric mean results of the various AUCs (ng.h.mL−1) are presented in the following table. Calculation of EE and ENG interaction/control ratios plus 90% confidence intervals confirmed the absence of PK interactions for both antibiotics. In both studies, NuvaRing with or without concomitant antibiotic therapy was well tolerated. These studies show an absence of PK interactions between NuvaRing and concomitant broad-spectrum antibiotics and indicate that NuvaRing is a reliable contraceptive option even in situations where users may require antibiotic treatment. Clinical Pharmacology & Therapeutics (2004) 75, P33–P33; doi: 10.1016/j.clpt.2003.11.124 Table 1. study I AUCday1 AUCday10 AUCday1–11 AUCday1–22 EE NR 0.32 0.25 5.58 11.1 NR + A 0.32 0.24 5.30 10.9 ENG NR 11.1 24.4 427 950 NR + A 10.2 24.9 427 959 study II AUCday1 AUCday10 AUCday1–11 AUCday1–22 EE NR 0.61 0.51 5.28 10.8 NR + D 0.58 0.48 5.02 10.3 ENG NR 19.9 42.7 363 811 NR + D 21.0 43.1 371 827

Exposure of isolated rat hepatocytes to allyl alcohol (AA), diethyl maleate (DEM) and bromoisovalerylurea (BIU) induced lipid peroxidation, depletion of free protein thiols to about 50% of the control value and cell death. Vitamin E completely prevented lipid peroxidation, protein thiol depletion and cell death. A low concentration (0.1 mM) of the lipophylic disulfide, disulfiram (DSF), also prevented the induction of lipid peroxidation by the hepatotoxins; however, in the presence of DSF, protein thiol depletion and cell death occurred more rapidly. Incubation of cells with a high concentration (10 mM) of DSF alone led to 100% depletion of protein thiols and cell death, which could not be prevented by vitamin E. The level of free protein thiols in cells, decreased to 50% by exposure to AA, DEM and BIU, could be reversed to 75% of the initial level by dithiothreitol (DTT) treatment, indicating that the protein thiols were partially modified into disulfides and partially into other, stable thiol adducts. The 100% depletion of protein thiols by DSF was completely reversed by DTT treatment. The involvement of lipid peroxidation in protein thiol depletion was studied by measuring the effect of a lipid peroxidation product, 4-hydroxynonenal (4-HNE), on protein thiols in a cell free liver fraction. 4-HNE did not induce lipid peroxidation in this system, but protein thiols were depleted to 30% of the initial value, irrespective of the presence of vitamin E. DTT treatment could reverse this for only 25%. Similar, DSF-induced protein thiol depletion could be reversed completely by DTT. We conclude that (at least) two types of protein thiol modifications can occur after exposure of hepatocytes to toxic compounds: one due to interaction of endogeneously generated lipid peroxidation products with protein thiols, which is not reversible by the action of DTT, and one due to a disulfide interchange between disulfides like DSF and protein thiols, which can be reversed by the action of DTT.

The relationship between lipid peroxidation and cell death, induced by a number of hepatotoxins, was studied in isolated rat hepatocytes. Disulfiram (DSF) and diethyldithiocarbamate (DDC) completely prevented lipid peroxidation, induced by allyl alcohol, tert-butyl hydroperoxide (t-BHP), diethyl maleate (DEM), bromoisovalerylurea (BIU) and carbon tetrachloride (CCl4). Lipid peroxidation was measured by the formation of both thiobarbituric acid positive material and conjugated dienes. However, DSF and DDC did not protect against cell death, induced by these hepatotoxins. In the presence of DSF or DDC, cell death occurred even earlier in time. We conclude that cell death can occur in the absence of lipid peroxidation. Therefore, lipid peroxidation is not a requisite for the induction of cell death.

For many years now the relation between lipid peroxidation and cell death, induced by xenobiotics, has been debated, the question being whether lipid peroxidation is the cause or the consequence of toxic events leading to cell death (Smith et al. 1983, Younes and Siegers 1981, Kappus and Muliawan 1982). A major defence system against lipid peroxidation is based on the reducing activity of glutathione (GSH) in which it is converted to the oxidized form (GSSG). Compounds that are conjugated with GSH can induce lipid peroxidation because they deplete GSH and therefore eliminate the defences against lipid peroxidation (Smith et al. 1983; Reiter and Wendel 1982). Acrolein is formed by alcohol dehydrogenase from the hepatotoxin allyl alcohol. It can be conjugated with GSH or it can be further oxidized to the nontoxic agent acrylic acid by aldehyde dehydrogenase. Recently it was demonstrated (Ohno et al. 1985) that acrolein is responsible for the toxic effects of allyl alcohol. The present study was undertaken to obtain a better insight into the relation between lipid peroxidation and cell death, induced by allyl alcohol and acrolein.

Isolated rat hepatocytes were incubated with ATP to induce high intracellular free Ca2+ concentrations as determined with the Quin-2 method. Immediately after addition of ATP, the intracellular concentration of Ca2+ rose from 200 nM to more than 2.5 microM. It stayed at this value during the first 1/2 h; the rise was absolutely dependent on extracellular Ca2+. After the first 1/2 h the Ca2+ concentration decreased to 1-2 microM (5-10 times the control value). These high intracellular free Ca2+ concentrations did not lead to an immediate loss of cell viability. Only after 2 h of incubation a substantial number of cells lost viability. This was preceded by a decrease in cellular NADH (greater than 40%) and accompanied by a sharp increase in the intracellular Ca2+ concentration. Under these conditions the NADPH concentration was not affected. Cellular GSH was decreased to 30% of the initial value, but no lipid peroxidation or protein-thiol depletion was observed. Intracellular ATP, ADP and AMP were increased in the presence of extracellular ATP. Ca2+-dependent proteases seemed not to be involved in cell death. These observations are consistent with a collapse of mitochondrial functions as a final trigger of cell death.