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Background: Brexpiprazole is a second-generation antipsychotic approved in Japan in 2018; however, information on placental passage and breast milk transfer remains limited. In this report, the patient, a 30-year-old pregnant woman with schizophrenia, was medicated with brexpiprazole, risperidone, and quetiapine., Methods: The study used high-performance liquid chromatography-tandem mass spectrometry to determine the concentrations of brexpiprazole, quetiapine, risperidone, and its active metabolite (paliperidone) in maternal and neonatal plasma, cord venous plasma, and breast milk. Maternal plasma samples were obtained approximately 2 and 8 hours after the last administration of antipsychotics on the day of delivery and at the estimated drugs' trough time on days 1, 3, and 5 after delivery., Results: The maternal plasma concentrations of brexpiprazole, quetiapine, and paliperidone increased by approximately 3.5-fold on the fifth day compared with those on the day of delivery, whereas the risperidone concentration remained almost constant. Moreover, the neonatal plasma concentrations of the 4 drugs immediately after birth were indistinguishable from the umbilical cord concentrations and gradually decreased, except for risperidone. Relative infant doses of these compounds were below 1.1%., Conclusions: Pregnancy status notably alters the pharmacokinetic properties of antipsychotics. Therefore, close and careful monitoring of clinical symptoms should be considered during pregnancy and after delivery. Although brexpiprazole is transferred to neonates through the placenta, breastfeeding is still possible because the relative infant dose value of this drug was much less than 10%., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Vicagrel, a novel irreversible P2Y 12 receptor inhibitor, is undergoing phase III trials for the treatment of acute coronary syndromes in China. In this study, we evaluated the pharmacokinetics, mass balance, and metabolism of vicagrel in six healthy male Chinese subjects after a single oral dose of 20 mg [ 14 C]vicagrel (120 µCi). Vicagrel absorption was fast (T max  = 0.625 h), and the mean t 1/2 of vicagrel-related components was ~38.0 h in both plasma and blood. The blood-to-plasma radioactivity AUC inf ratio was 0.55, suggesting preferential distribution of drug-related material in plasma. At 168 h after oral administration, the mean cumulative excreted radioactivity was 96.71% of the dose, including 68.03% in urine and 28.67% in feces. A total of 22 metabolites were identified, and the parent vicagrel was not detected in plasma, urine, or feces. The most important metabolic spot of vicagrel was on the thiophene ring. In plasma pretreated with the derivatization reagent, M9-2, which is a methylated metabolite after thiophene ring opening, was the predominant drug-related component, accounting for 39.43% of the radioactivity in pooled AUC 0-8 h plasma. M4, a mono-oxidation metabolite upon ring-opening, was the most abundant metabolite in urine, accounting for 16.25% of the dose, followed by M3-1, accounting for 12.59% of the dose. By comparison, M21 was the major metabolite in feces, accounting for 6.81% of the dose. Overall, renal elimination plays a crucial role in vicagrel disposition, and the thiophene ring is the predominant metabolic site., (© 2020. CPS and SIMM.)

A hollow fiber liquid phase microextraction (HF-LPME) based on a reversed lipid micelle as the extraction phase was proposed and combined with high performance liquid chromatography (HPLC) for the determination of rotigotine in biological matrix. In the proposed procedure, pieces of hollow fibers were fastened on a magnetic stir bar using a thread to provide better precision. Rotigotine was extracted from 5 mL of diluted plasma sample phase with pH 6 into reversed lipid micelle (5 mmol/L of dipalmitoyl phosphatidyl choline in n-octanol/water) impregnated in both the wall pores and the lumen of the hollow fiber. After the extraction at 900 rpm and room temperature for 30 min, the acceptor phase of reversed lipid micelle was collected for HPLC analysis. Various parameters affecting the extraction efficiency, such as type of surfactant and organic solvent, surfactant concentration, sample phase pH, salt amount, extraction time, stirring rate, and dilution factor of the plasma sample, were investigated and optimized. Furthermore, the formed reversed lipid micelle was characterized by fluorescence method. Under the optimal conditions, the linear range of rotigotine was between 2 ng/mL and 100 ng/mL with determination coefficient (r 2 ) ≥ 0.9913. It is shown from results of method validation that the satisfactory accuracy (the relative errors between -8.5% and 3.3%), precision (the relative standard deviations from 3.8% to 8.9%), stability and matrix effect were obtained. The enrichment factor (EF) of the reversed lipid micelle-based HF-LPME for rotigotine reached 126. And the feasibility of the proposed method was confirmed by the application to the pharmacokinetic study of rotigotine in rat plasma., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Alpha-Pyrrolidinopentiothiophenone (α-PVT) belongs to the drug class of pyrrolidinophenones, a subgroup of synthetic cathinones, which are among the most prevalent new psychoactive substances. The study describes a series of 44 authentic forensic cases with analytical confirmed intake of α-PVT. Plasma concentrations, determined by a validated LC-MS/MS method, ranged from ca. 0.9 to 306 µg/L (median 35.6; mean 66.6 µg/L). Comprehensive toxicological analysis proved excessive co-consumption in almost all cases, including other pyrovalerones and classic stimulants as well as central depressant drugs such as opiates/opioids, benzodiazepines, pregabalin and/or ethanol. Subjects were aged between 26 and 54 years (median 35 years, mean 36 years) and appeared to be mainly experienced intravenous drug consumers. A high incidence of aberrant behavior in terms of aggressive, combative behavior and psychotic changes could be observed, as also reflected in accused offences, which frequently presented violent crimes. In consideration of several confounding factors, the study suggests a relationship between frequency of such impairment and plasma concentrations of α-PVT, but individual cases without signs of behavioral changes and high plasma concentrations also occurred, which might be explained by developed tolerance and/or individual vulnerably for the psychotic effects of pyrovalerones., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this study, a new analytical method for erdosteine (ERD) in plasma based on high-performance liquid chromatography and a fluorimetric detector, is presented. Precolumn derivatization of ERD with 4-bromomethyl-7-methoxy coumarin (BrMmC) and dibenzo-18-crown-6-ether as a reaction catalyst led to the production of a fluorescent compound. ERD was monitored by fluorescence with an excitation wavelength λ ext. = 325 nm and emission wavelength λ em. = 390 nm. Optimum reaction conditions were carefully studied and optimized. A chromatographic procedure was performed using a C18 column of 150 × 4.6 mm and 3 μm particle size and a mobile phase consisting of methanol:acetonitrile:water (30:30:40, v/v/v) under a flow rate of 0.5 ml min -1 . A calibration plot was established covering analyte concentration range 0.2-3.0 μg ml -1 ; the detection limit was 0.015 μg ml -1 and quantification limit was 0.05 μg ml -1 . Mean recovery was 87.33% and relative standard deviation was calculated to be less than 4.4%. The developed method was successfully used to determine pharmacokinetic preparations of ERD subsequent to administration of a 900 mg dose capsule to a healthy 40-year-old woman volunteer., (© 2020 John Wiley & Sons, Ltd.)

Oliceridine is a G protein-biased ligand at the μ-opioid receptor in development for treatment of moderate to severe acute pain. A phase 1, open-label, single-dose study investigated the pharmacokinetics and safety of oliceridine 0.5 mg intravenous (IV) in subjects with end-stage renal disease (ESRD, n = 9) versus 1 mg in healthy controls (n = 8). A second phase 1, open-label, single-dose study investigated the pharmacokinetics and safety of a 0.5-mg IV dose in hepatic impairment (mild, n = 10; moderate, n = 10; severe, n = 6) versus 1 mg in healthy controls (n = 8). The controls were sex and age (±10 years) matched. In ESRD versus healthy subjects, no difference in clearance was observed between ESRD patients and subjects with normal renal function. Oliceridine clearance and AUC were not affected by hepatic impairment. Half-life (hours; GM [%CV]) increased in subjects with moderate (4.3 [44.1]) and severe (5.8 [41.2]) impairment versus mild impairment (2.6 [20.0]) and healthy subjects (2.1 [11.3]). Volume of distribution was increased with the degree of hepatic impairment. All adverse events were mild and generally consistent with the known safety profile of oliceridine. No dose adjustment is needed in patients with renal impairment or in patients with mild or moderate hepatic impairment. Initial dose reduction should be considered in severe hepatic impairment, and patients may require fewer doses of oliceridine due to the longer half-life observed in these patients., (© 2019 The Authors. Clinical Pharmacology in Drug Development published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.)

Endothelin receptor antagonists (ERAs) such as, ambrisentan, macitentan and sitaxentan are primarily used for the treatment of pulmonary arterial hypertension. Considering the rise in endothelin in pre-eclampsia, ERAs may also be useful in its treatment. To evaluate the pharmacokinetics of ERAs, a rapid ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated to determine the concentration of ambrisentan, macitentan and sitaxentan in human plasma. Plasma samples were treated with methanol to induce protein precipitation. A chromatographic separation was performed on a C 18 column using a gradient of methanol-water containing 0.1% formic acid and 0.013% ammonium acetate and a flow rate of 0.5 ml/min. Multiple reaction monitoring was used for quantification. This method was validated in a linear range of 20.28-2028 μg/l for ambrisentan, 4.052-405.2 μg/l for macitentan and 205.4-10 270 μg/l for sitaxentan. The method was successfully validated according to US Food and Drug Administration guidelines to determine the concentrations of macitentan, ambrisentan and sitaxentan in human plasma. This method is now being used for study samples and clinical patient samples., (© 2019 John Wiley & Sons, Ltd.)

Aim: A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as an analytical method for the quantitative determination of eight antifungal drugs in spiked human plasma has been described optimized and validated., Materials and Methods: The analyzed compounds were voriconazole (VOR), luliconazole (LUL), clotrimazole (CLO), tioconazole (TIO), posaconazole (POS), ketoconazole (KET), sertaconazole (SER) and terconazole (TER)., Results: The separation of the analyzed compounds was conducted using a novel pentabromobenzyl column known as COSMOSIL PBB-R (150 mm × 4.6 mm I.D., particle size 5 μm). The analysis of the studied drugs was determined within 14 min using a diode array detector and the mobile phase consisted of: 10 mM potassium dihydrogen phosphate buffer (pH 2.1): Methanol (2: 98 v/v). A linear response was observed for all compounds in the range of concentration studied. Sample preparation was done through liquid-liquid extraction using diethyl ether., Conclusion: This proposed method was validated in terms of linearity, limit of quantification, limit of detection, accuracy, precision and selectivity. The method was successfully applied for the determination of these drugs in their pharmaceutical formulations and in human plasma samples., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The methods for quantification of highly potent analgesic agent (2R,4aR,7R,8aR)-4,7-dimethyl-2-(thiophen-2-yl)octahydro-2H-chromen-4-ol in rat whole blood and plasma were developed and validated using dried matrix spots (DMS) or fabric phase sorptive extraction (FPSE) techniques in combination with LC-MS/MS. 2-Adamantylamine hydrochloride was used as an internal standard (IS). Chromatographic separation was carried out on a reversed-phase column (2.0×75 mm, 5 μm) using water containing 0.1% formic acid and methanol containing 0.1% formic acid as mobile phases in gradient mode at a flow rate of 200 μL/min. The mass spectrometric detection was performed using electrospray ionization (ESI) in positive ion mode. MRM transitions were m/z 284.5 → 137.2/157.4 for the analgesic agent and m/z 152.3 → 93.1/107.2 for IS. Calibration curves were linear within 20-5000 ng/mL in dried plasma spots (DPS) or dried blood spots (DBS) experiments. The linearity was obtained in the range of 20-5000 ng/mL and 50-5000 ng/mL for plasma-FPSE and blood-FPSE experiments, respectively. The intra- and inter-day accuracy and precision did not exceed acceptable limits. The mean extraction recovery (%) was 26 for DPS, 25 for DBS, 38 for plasma-FPSE, 31 for blood-FPSE., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Sulfolane is an industrial solvent commonly used for extraction of aromatic hydrocarbons in the oil refining process, as well in the purification of natural gas. Its wide use and high solubility in water has led to contamination of groundwater. The objective of this work was to develop and validate an analytical method to quantitate sulfolane in rodent plasma in support of the National Toxicology Program toxicology and toxicokinetic studies of sulfolane. The method uses extraction of plasma with ethyl acetate and analysis by gas chromatography-mass spectrometry with electron ionization. The method was validated in male Sprague Dawley (SD) rat plasma over the concentration range of 20-100,000 ng/mL. The method was linear (r ≥ 0.99), accurate (mean relative error (RE) ≤ ±5.1%) and precise (relative standard deviation (RSD) ≤ 2.9%). The absolute recovery was ≥74%. The limit of detection was 0.516 ng/mL. Standards as high as ~2.5 mg/mL could be successfully diluted into the calibration range (mean %RE ≤ ±4.5; %RSD ≤ 4.6). Extracted samples were stable for at least 3 days at ambient and refrigerated temperatures, and freeze/thaw stability in matrix was demonstrated after three cycles over 3 days (calculated concentrations within 90.8-102% of Day 0 concentrations). Sulfolane was stable in frozen plasma for at least 75 days at -80°C (calculated concentrations within 93.0-98.1% of Day 0 concentrations). Matrix evaluation was performed for sulfolane in female SD rat plasma and male and female B6C3F1 mouse plasma (mean %RE ≤ ±4.9; %RSD ≤ 3.3). These data demonstrate that the method is suitable for determination of sulfolane in rodent plasma., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background : The prothrombin time may be used to monitor the plasma concentration of rivaroxaban. However, there is variability in the responsiveness of rivaroxaban to different thromboplastins. We aimed to develop a rivaroxaban-monitoring method using the prothrombin time to reduce the differences in the sensitivity among reagents. Methods : Rivaroxaban-spiked pooled normal plasma at a 0-1000 ng/ml concentration was used to generate a rivaroxaban-adjusted sensitivity index (SI) values, and was tested with three thromboplastins. The warfarin-adjusted international sensitivity index (ISI-warfarin), rivaroxaban-adjusted sensitivity index (SI-rivaroxaban), international normalized ratio (INR) calculated with ISI-warfarin, normalized ratio (NR) calculated with SI-rivaroxaban, and their coefficient of variances (CVs) were compared. The NR-rivaroxaban value was compared with the results of an anti-Xa assay. Results : The ISI-warfarin and SI-rivaroxaban using different thromboplastins were 1.02 and 1.88, respectively, with Thromborel S, 0.90 and 1.00 using Recombiplastin 2G, and 1.30 and 1.15 using Neoplastin CI-plus. Between-thromboplastin variability expressed as CV were 6.3%-25.1% when expressed as INR-warfarin and 1.7%-4.7% when expressed as NR-rivaroxaban. CVs for the NR-rivaroxaban with another laboratory were significantly lower than those for INR-warfarin. Anti-Xa assay v NR-rivaroxaban correlation coefficients were 0.97-0.99. Conclusion : Using a rivaroxaban-specific NR effectively minimises inter-thromboplastin variability. By utilizing a NR-rivaroxaban, standardized prothrombin time results could be rapidly obtained, especially useful in standardizing the therapeutic effect of rivaroxaban.

Rationale: Brexpiprazole is a novel serotonin-dopamine activity modulator approved by the USFDA in July 2015 for the treatment of schizophrenia and as an adjunctive therapy with other antidepressants for major depressive disorder in adults. However, limited numbers of metabolites are reported in the literature for brexpiprazole. Our prime intent behind this study is to revisit metabolite profiling of brexpiprazole and to identify and characterize all possible in vitro and in vivo metabolites., Methods: Firstly, the site of metabolism for brexpiprazole was predicted by a Xenosite web predictor model. Secondly, in vitro metabolite profiling was performed by incubating the drug individually with rat liver microsomes, human liver microsomes and rat S9 fraction at 37°C for 1 h in incubator shaker. Finally, for in vivo metabolite identification, a 50 mg kg -1 dose of brexpiprazole was administered to male Sprague-Dawley rats and the presence of various metabolites was confirmed in rat plasma, urine and feces., Results: The predicted atomic site of metabolism was obtained as a color gradient by the Xenosite web predictor tool and, from this study, probable metabolites were listed. In total, 14 phase I and 2 phase II metabolites were identified and characterized in the in vitro and in vivo matrices using ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UHPLC/QTOF-MS/MS). The majority of metabolites were found in the sample incubated with human liver microsomes and in rat urine, while in the other matrices only a few metabolites were detected., Conclusions: All the 16 metabolites were identified and characterized using UHPLC/QTOF-MS/MS. The study revealed that brexpiprazole is metabolized via hydroxylation, glucuronidation, S-oxidation, N-oxidation, dioxidation, oxidative deamination, N-dealkylation, etc., (© 2019 John Wiley & Sons, Ltd.)

Background and Objectives: Vicagrel, a novel thienopyridine antiplatelet agent, is an analogue of clopidogrel in development for the treatment of acute coronary syndromes. This study investigated the pharmacokinetic properties of vicagrel after single oral dosing with a direct comparison with clopidogrel in healthy Chinese subjects in the first two phase I clinical studies. The relationship between the exposure to the active metabolite and the platelet reactivity was also assessed for vicagrel., Methods: Study A was a single-ascending-dose study of vicagrel (5-75 mg) compared with clopidogrel (75 mg) in 67 healthy volunteers. Study B was a randomized, two-period, crossover, loading-dose study of vicagrel 20 mg compared with clopidogrel 300 mg in 12 healthy subjects. Plasma concentrations of three common metabolites of vicagrel and clopidogrel, the active thiol metabolite H4, the inactive thiol metabolite H3, and the S-methylated form of H3 (SM3, the major metabolite of vicagrel), were determined using a validated UHPLC-MS/MS method. The relationship between the AUC 0-t of active H4 and the P2Y 12 reaction units at 4 h after administration of vicagrel was investigated. Blood concentrations of vicagrel were determined after a single oral administration of vicagrel 25 mg to two healthy Chinese subjects., Results: In the single-ascending-dose study, vicagrel was metabolized rapidly with the median t max for the three metabolites, namely, H4, H3, and SM3, ranging from 0.25-1.75 h. The pharmacokinetics of the three metabolites for vicagrel were linear across the dose range of 5-75 mg, with the mean C max and AUCs for H4 and H3 increasing in an approximately 1:1 dose-proportional manner and for SM3 increasing in a <1:1 dose-proportional manner. The median t max for active H4 in the vicagrel 5 mg group was slightly shorter than that in the clopidogrel 75 mg group (0.50 versus 0.75 h). The mean AUC 0-t for H4 in the vicagrel 5 mg group was similar to that in the clopidogrel 75 mg group (11.7 versus 11.8 ng∙h/mL). The AUC 0-t of active H4 was apparently associated with the P2Y 12 reaction units at 4 h for vicagrel. In the loading-dose study, for active H4, the median t max was slightly shorter (0.50 versus 0.75 h) and the mean AUC 0-t was 29% higher in the vicagrel 20 mg group than those in the clopidogrel 300 mg group. After a single oral administration of vicagrel 25 mg to 2 subjects, vicagrel was detected in blood but in very low concentrations., Conclusions: Vicagrel was rapidly and extensively metabolized, and the levels of the parent drug in circulation were very low. The pharmacokinetics of the three metabolites of vicagrel were linear and predictable across the dose range of 5-75 mg. The AUC of active H4 was apparently associated with the P2Y 12 reaction units for vicagrel. For active H4, vicagrel 5 mg produced similar exposure (AUC) with more rapid appearance compared with clopidogrel 75 mg, and vicagrel 20 mg produced even slightly higher exposure (AUC) with more rapid appearance compared with clopidogrel 300 mg in humans., Trial Registration: CTR20150346, CTR20160379., (Copyright © 2018. Published by Elsevier B.V.)

Avatrombopag, a c-Mpl agonist, has been developed to provide an alternative therapy to standard platelet transfusion care for the treatment of thrombocytopenia. The main objectives of this article were to describe the pharmacokinetics (PK) of avatrombopag, to characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship between plasma avatrombopag concentrations and platelet count, and to identify potential intrinsic and extrinsic factors affecting PK or PK/PD in patients with chronic liver disease (CLD). Platelet count following avatrombopag administration with and without concomitant medication was further simulated using the final population PK/PD model to explore potential dose adjustments. Avatrombopag PK was described by a 1-compartment model with combined first- and zero-order absorption and linear elimination. The relationship between the plasma avatrombopag concentrations and platelet count was well described by a 6-compartment life-span model with a linear drug effect. The final PK and PK/PD models included statistically significant but not clinically relevant effects of body weight and CLD on apparent volume distribution and East Asian ethnicity, albumin, and thrombopoietin level on the slope parameter in the PK/PD relationship. PK/PD simulations showed comparable elevation in platelet count with and without concomitant cytochrome P450 (CYP) 3A and CYP2C9 inhibitors for the dosing regimens of 40 and 60 mg for 5 days, with predictions of <10% of CLD patients exceeding platelet count >200 × 10 9 /L. Dose adjustment is therefore not necessary with concomitant use of CYP3A and CYP2C9 interacting drugs considering the limited treatment duration (ie, 5 days) and lack of significant safety concerns in CLD patients., (© 2018, The American College of Clinical Pharmacology.)

Vicagrel, a novel acetate analogue of clopidogrel, exerts more potent antiplatelet effect than clopidogrel in rodents. Relevant evidence indicated that aspirin and vicagrel are the drug substrate for carboxylesterase 2. Accordingly, it is deduced that concomitant use of aspirin could attenuate the bioactivation of and platelet response to vicagrel. To clarify whether there could be such an important drug-drug interaction, the differences in both the formation of vicagrel active metabolite H4 and the inhibition of adenosine diphosphate-induced platelet aggregation by vicagrel were measured and compared between mice treated with vicagrel alone or in combination with aspirin. The plasma H4 concentration was determined by liquid chromatography-tandem mass spectrometry, and the inhibition of platelet aggregation by vicagrel was assessed by whole-blood platelet aggregation. Compared with vicagrel (2.5 mg·kg) alone, concurrent use of aspirin (5, 10, or 20 mg·kg) significantly decreased systemic exposure of H4, an average of 38% and 41% decrease in Cmax and AUC0-∞ in mice when in combination with aspirin at 10 mg·kg, respectively. Furthermore, concomitant use of aspirin (10 mg·kg) and vicagrel (2.5 mg·kg) resulted in an average of 66% reduction in the inhibition of adenosine diphosphate-induced platelet aggregation by vicagrel. We conclude that aspirin significantly attenuates the formation of vicagrel active metabolite H4 and platelet response to vicagrel in mice, and that such an important drug-drug interaction would appear in clinical settings if vicagrel is taken with aspirin concomitantly when marketed in the future.

A sensitive, efficient and stable bioanalytical method has been developed and validated for determination of brexpiprazole in dog plasma with UPLC-MS-MS for the first time. Brexpiprazole and internal standard were extracted from plasma samples by liquid-liquid extraction and separated on an Acquity UPLC BEH C18 column. A gradient elution program was developed employing methanol and 10 mM ammonium acetate aqueous solution as mobile phases. The method was validated for parameters of selectivity, LLOQ, linearity, accuracy, precision, matrix effects and stability in accordance with the regulatory guidance on bioanalytical method validation. The validated method was applied in evaluating the pharmacokinetic profiles of brexpiprazole in beagle dogs after a single-dose oral administration of a 4 mg tablet.

Background and Objective: Pharmacokinetic studies using deconvolution methods and non-compartmental analysis to model clinical absorption of drugs are not well represented in the literature. The purpose of this research was (1) to define the system of equations for description of rotigotine (a dopamine receptor agonist delivered via a transdermal patch) absorption based on a pharmacokinetic model and (2) to describe the kinetics of rotigotine disposition after single and multiple dosing., Methods: The kinetics of drug disposition was evaluated based on rotigotine plasma concentration data from three phase 1 trials. In two trials, rotigotine was administered via a single patch over 24 h in healthy subjects. In a third trial, rotigotine was administered once daily over 1 month in subjects with early-stage Parkinson's disease (PD). A pharmacokinetic model utilizing deconvolution methods was developed to describe the relationship between drug release from the patch and plasma concentrations. Plasma-concentration over time profiles were modeled based on a one-compartment model with a time lag, a zero-order input (describing a constant absorption via skin into central circulation) and first-order elimination. Corresponding mathematical models for single- and multiple-dose administration were developed., Results: After single-dose administration of rotigotine patches (using 2, 4 or 8 mg/day) in healthy subjects, a constant in vivo absorption was present after a minor time lag (2-3 h). On days 27 and 30 of the multiple-dose study in patients with PD, absorption was constant during patch-on periods and resembled zero-order kinetics., Conclusion: Deconvolution based on rotigotine pharmacokinetic profiles after single- or multiple-dose administration of the once-daily patch demonstrated that in vivo absorption of rotigotine showed constant input through the skin into the central circulation (resembling zero-order kinetics). Continuous absorption through the skin is a basis for stable drug exposure.

Purpose: The pharmacokinetic (PK) profile of the rotigotine transdermal patch is well characterized in Caucasian patients with Parkinson's disease (PD) but not in Chinese subjects. This article reports the PK variables, safety, and tolerability of the rotigotine transdermal patch (2 mg/24 hours and 4 mg/24 hours cold-chain PR2.1.1 formulation) in healthy Chinese subjects (SP0913; NCT01675024). A second study (PD0011; NCT02070796) evaluated the relative bioavailability of cold-chain (PR2.1.1) and room temperature-stable (PR2.2.1) formulations of rotigotine in healthy Chinese men., Methods: In treatment period 1 of SP0913, subjects received a single application of rotigotine 2 mg/24 hours on day 1 followed by a washout period (days 2-6); treatment period 2 (days 6-14) involved multiple doses of rotigotine 2 mg/24 hours (days 7-9) followed by multiple doses of rotigotine 4 mg/24 hours (days 10-12), with patches applied for 24 hours each. In PD0011, subjects received a single dose (2 mg/24 hours) of each rotigotine formulation (PR2.2.1 and PR2.1.1) for 24 hours each in a crossover design. Blood samples were collected at scheduled time points to determine rotigotine plasma concentrations. Safety and tolerability were evaluated by adverse events monitoring., Results: Twenty-four healthy Chinese subjects (12 males, 12 females) were enrolled and completed SP0913. Geometric mean plasma concentrations of unconjugated and total rotigotine increased to a plateau beginning at ∼8 hours (multiple dose) to 16 hours (single dose) postdose; no characteristic T max was observed for unconjugated and total rotigotine. The respective geometric mean C max , C max,ss , AUC from zero up to the last analytically quantifiable concentration, and AUC 0-24,ss values for unconjugated and total rotigotine were similar when rotigotine 2 mg/24 hours was applied as a single dose or multiple-dose regimen. During the multiple-dose period, geometric mean C max,ss and AUC 0-24,ss of both unconjugated and total rotigotine were ∼2-fold higher for rotigotine 4 mg/24 hours than for rotigotine 2 mg/24 hours. Forty-seven of 50 male Chinese subjects completed PD0011. Primary PK parameters for the room temperature-stable formulation of rotigotine were highly comparable to the cold-chain formulation. Common adverse events included application site pruritus, nausea, dizziness, and constipation (SP0913 only), with no clinically significant changes in other safety measures., Implications: PK profiles and derived PK parameters of unconjugated and total rotigotine in healthy Chinese subjects were consistent with findings from other ethnic groups receiving single and multiple doses of the rotigotine transdermal patch. Single and repeated daily doses of the rotigotine transdermal patch were well tolerated. Room temperature-stable and cold-chain formulations were bioequivalent. ClinicalTrials.gov identifiers: NCT01675024 and NCT02070796., (Copyright © 2018 Elsevier Inc. All rights reserved.)

AZD3965, a pyrole pyrimidine derivative, is a potent and orally bioavailable inhibitor of monocarboxylate transporter 1 (MCT1), currently in a Phase I clinical trial in UK for lymphomas and solid tumors. There is currently no published assay for AZD3965. The objectives of this study were to develop and validate a LC/MS/MS assay for quantifying AZD3965 in mouse plasma and tumor tissue. Protein precipitation with 0.1% formic acid in acetonitrile was used for sample preparation. Chromatographic separation was achieved on a C18 column followed by tandem mass spectrometry detection in multiple reaction monitoring mode with utilizing Atmospheric Pressure Chemical Ionization. AR-C155858 was used as the internal standard. The inter-day and intra-day precision and accuracy of quality control samples evaluated in plasma and tumor tissue were less than ±7% of the nominal concentrations. The extraction recovery, matrix effect and stability values were all within acceptable levels. Sample dilution integrity, accessed by diluting plasma spiked with AZD3965 10-fold with blank plasma, was 101%. The lower limit of quantification (LLOQ) and upper limit of quantification (ULOQ) were 0.15 ng/mL and 12 μg/mL, respectively, in plasma. The assay of AZD3965 in tumor tissue was also validated with good precision and accuracy. The LLOQ was 0.15 ng/mL in tumor tissue. This assay was successfully applied to pharmacokinetic and murine 4T1 breast tumor xenograft studies of AZD3965 in mice., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aim: Hemay005 is a novel small-molecule inhibitor of phosphodiesterase-4 developed for the treatment of psoriasis. Measurement of Hemay005 in biological samples is critical for evaluation of its pharmacokinetics in clinical studies. Methodology & results: Plasma and urine samples were extracted and then chromatographed on an Acquity UPLC HSS T3 column with a gradient elution. Detection was performed on a Xevo TQ-S tandem mass spectrometer using negative ESI., Conclusion: For the first time, a sensitive and robust ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established and validated for the quantitative determination of Hemay005 in human plasma and urine, and it was successfully applied to evaluate the pharmacokinetics of Hemay005 in healthy subjects in a first-in-human study.

Conventional opioids bind to μ-opioid receptors and activate 2 downstream signaling pathways: G-protein coupling, linked to analgesia, and β-arrestin recruitment, linked to opioid-related adverse effects and limiting efficacy. Oliceridine (TRV130) is a novel G protein-biased ligand at the μ-opioid receptor that differentially activates G-protein coupling while mitigating β-arrestin recruitment. Using data derived from both phase 1 studies in healthy volunteers as well as data from a phase 2 study examining the efficacy of oliceridine for the treatment of postbunionectomy pain, we have developed a population pharmacokinetic/pharmacodynamic model linking the pharmacokinetics of oliceridine to its effect on pain, as measured by the Numeric Pain Rating Scale score. Phase 1 data consisted of 145 subjects (88% male, 12% female), who received single doses of oliceridine ranging between 0.15 and 7 mg, as well as multiple doses ranging from 0.4 to 4.5 mg every 4-6 hours. Sixteen of these subjects were CYP2D6 poor metabolizers, who have lower oliceridine clearance than extensive metabolizers. Approximately 265 subjects (10% male, 90% female) came from the phase 2 study, in which they received active doses ranging from 0.5 to 4 mg every 3-4 hours. The final model was a 3-compartment model that included covariates of body weight, sex, and CYP2D6 status. The PD model was an indirect response model linked to plasma oliceridine concentrations and included the placebo pain response over the 48-hour treatment period. The EC 50 for oliceridine on pain relief was estimated as 10.1 ng/mL (95%CI, 8.4-12.1 ng/mL). Model qualification showed that the model robustly reproduced the original data., (© 2018, The American College of Clinical Pharmacology.)

Oliceridine is a novel G protein-biased ligand at the μ-opioid receptor that differentially activates G protein coupling while mitigating β-arrestin recruitment. Unlike morphine, oliceridine has no known active metabolites; therefore, analgesic efficacy is predictably linked to its concentration in the plasma. Oliceridine is primarily hepatically metabolized by CYP3A4 and CYP2D6. Using a pharmacokinetic/pharmacodynamic model relating oliceridine plasma concentrations to its effect on pain intensity as measured by numeric pain-rating scale (NPRS) scores, we have simulated potential dosing regimens using both fixed-dose regimens and as-needed (prn) dosing regimens in which various doses of oliceridine were administered if NPRS scores indicated moderate to severe pain (≥4 on a 0-10 scale). In addition, regimens in which oliceridine was self-administered via a patient-controlled analgesia device were also simulated. The simulated population included 10% CYP2D6 poor metabolizers (PM). The simulation results suggest that oliceridine doses of 1-3 mg prn should be effective in reducing NPRS scores relative to placebo. The simulations also revealed that a 1-mg "supplemental dose" given 0.25 hour after the loading dose would decrease NPRS scores further in almost one-third of patients. In addition, if oliceridine is administered prn, a longer interval between doses is observed in simulated PM patients, consistent with their reduced oliceridine clearance. Because this longer average dosing interval is predicted to decrease oliceridine exposure in PM patients, the need to know the patient's CYP2D6 genotype for dosing is effectively obviated., (© 2018, The American College of Clinical Pharmacology.)

Allosteric phosphodiesterase 4 (PDE4) inhibitors are highly sought after due to their important anti-inflammatory and anti-cancer therapeutic effects. We recently identified Eggmanone, an extraordinarily selective allosteric PDE4 inhibitor displaying favorable drug properties. However, a specific analytic method of Eggmanone in serum and its pharmacokinetics have not been reported yet. In this study, we developed a rapid and sensitive high performance liquid chromatography-mass spectrometric (HPLC-MS/MS) method to determine Eggmanone concentrations in rat plasma. This assay method was validated in terms of specificity, linearity, sensitivity, accuracy, precision, matrix effect, recovery and stability, and was applied to a pharmacokinetic study in rats following intravenous injection of Eggmanone at doses of 1 and 3 mg/kg. The lower limit of quantification (LLOQ) of this assay was 5 ng/mL and the linear calibration curve was acquired with R 2  > 0.99 between 5 and 1000 ng/m. The intra-day and inter-day precision was evaluated with the coefficient of variations less than 11.09%, whereas the mean accuracy ranged from 98.38% to 105.13%. The assay method exhibited good recovery and negligible matrix effect. The samples were stable under all the experimental conditions. The plasma concentrations of Eggmanone were detected and quantified over 24 h with the terminal elimination half-live of 3.57 ± 1.80 h and 5.92 ± 3.34 h for the low dose (1 mg/kg) and high dose (3 mg/kg) respectively. In summary, the present method provides a robust, fast and sensitive analytical approach for quantification of Eggmanone in plasma and was successfully applied to a pharmacokinetic study in rats., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aims: Avatrombopag, a thrombopoietin receptor agonist, is a substrate of cytochrome P450 (CYP) 2C9 and CYP3A. We assessed three drug-drug interactions of avatrombopag as a victim with dual or selective CYP2C9/3A inhibitors and inducers., Methods: This was a three-part, open-label study. Forty-eight healthy subjects received single 20 mg doses of avatrombopag alone or with one of 3 CYP2C9/3A inhibitors or inducers: fluconazole 400 mg once daily for 16 days, itraconazole 200 mg twice daily on Day 1 and 200 mg once daily on Days 2-16, or rifampicin 600 mg once daily for 16 days. Pharmacokinetics, pharmacodynamics (platelet count) and safety of avatrombopag were evaluated., Results: Coadministration of a single 20-mg dose of avatrombopag with fluconazole at steady-state resulted in 2.16-fold increase of AUC of avatrombopag, prolonged terminal elimination phase half-life (from 19.7 h to 39.9 h) and led to a clinically significant increase in maximum platelet count (1.66-fold). Itraconazole had a mild increase on both avatrombopag pharmacokinetics and pharmacodynamics compared to fluconazole. Coadministration of rifampicin caused a 0.5-fold decrease in AUC and shortened terminal elimination phase half-life (from 20.3 h to 9.84 h), but has no impact on maximum platelet count. Coadministration with interacting drugs was found to be generally safe and well-tolerated., Conclusions: The results from coadministration of fluconazole or itraconazole suggest that CYP2C9 plays a more predominant role in metabolic clearance of avatrombopag than CYP3A. To achieve comparable platelet count increases when avatrombopag is coadministered with CYP3A and CYP2C9 inhibitors, an adjustment in the dose or duration of treatment is recommended, while coadministration with strong inducers is not currently recommended., (© 2018 The British Pharmacological Society.)

Significant neuroprotective effects of angiotensin II type 2 (AT 2 ) receptor (AT 2 receptor) agonists in ischemic stroke have been previously demonstrated in multiple studies. However, the routes of agonist application used in these pre-clinical studies, direct intracerebroventricular (ICV) and systemic administration, are unsuitable for translation into humans; in the latter case because AT 2 receptor agonists are blood-brain barrier (BBB) impermeable. To circumvent this problem, in the current study we utilized the nose-to-brain (N2B) route of administration to bypass the BBB and deliver the selective AT 2 receptor agonist Compound 21 (C21) to naïve rats or rats that had undergone endothelin 1 (ET-1)-induced ischemic stroke. The results obtained from the present study indicated that C21 applied N2B entered the cerebral cortex and striatum within 30 min in amounts that are therapeutically relevant (8.4-9 nM), regardless of whether BBB was intact or disintegrated. C21 was first applied N2B at 1.5 h after stroke indeed provided neuroprotection, as evidenced by a highly significant, 57% reduction in cerebral infarct size and significant improvements in Bederson and Garcia neurological scores. N2B-administered C21 did not affect blood pressure or heart rate. Thus, these data provide proof-of-principle for the idea that N2B application of an AT 2 receptor agonist can exert neuroprotective actions when administered following ischemic stroke. Since N2B delivery of other agents has been shown to be effective in certain human central nervous system diseases, the N2B application of AT 2 receptor agonists may become a viable mode of delivering these neuroprotective agents for human ischemic stroke patients., (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Avatrombopag, an orally administered, small-molecule thrombopoietin receptor (c-Mpl) agonist, is currently in clinical development for the potential treatment of severe thrombocytopenia in patients with chronic liver disease undergoing an elective procedure. The objectives of this study were to characterize and compare the pharmacokinetics (including the food effect) and pharmacodynamics (platelet count) of avatrombopag following single doses in Japanese and white subjects. Following single dosing under fasted and fed conditions, mean peak concentrations occurred at 5 to 8 hours and subsequently declined with a half-life of 16 to 18 hours in Japanese and white subjects. Administration with food did not alter the rate or extent of avatrombopag absorption but substantially reduced pharmacokinetic variability relative to the fasted state. CYP2C9 polymorphism (*2, *3) was associated with higher pharmacokinetic variability but not with any clinically important effect on variability in platelet response. Plasma exposures of avatrombopag increased in a dose-proportional manner over the dose range tested. After a single dose, platelet count increased in a dose-related manner, reaching a maximum by day 11 and returning to baseline levels by day 27. No clinically important differences were found when avatrombopag pharmacokinetics and pharmacodynamics were compared between Japanese and white subjects. Administration of avatrombopag was generally well tolerated., (© 2017, The American College of Clinical Pharmacology.)

Biochemical investigations performed in cases of mechanical asphyxia have provided diverging information over time. The purpose of the study presented herein was threefold: to investigate the postmortem stability of a series of molecules (thyroglobulin, iodothyronines, calcitonin, and parathyroid hormone) in blood after death, to determine the same molecules in a series of cases of suicidal hangings for which antemortem serum samples were available, and to measure the same molecules in postmortem serum obtained from different sampling sites thereby evaluating the distribution of these molecules in the specific samples. Preliminary results indicated postmortem stability of thyroglobulin, calcitonin, and parathyroid hormone levels, decreasing total and free T4 levels, and increasing total and free T3 concentrations. Our findings also showed that antemortem mechanical force applied to the neck region (hanging cases) may be accompanied by increased thyroglobulin in peripheral (femoral) blood, though a certain number of cases with nonincreased thyroglobulin levels may be observed. Lastly, our results revealed that hanging, manual, and ligature strangulation cases may be accompanied by increased thyroglobulin, total T3, and free T3 values in postmortem serum specimens obtained from blood sampled at different sampling sites, even in the absence of microscopically identified thyroid gland tissue damage. Such increases are more constant and important in arterial and venous blood samples obtained from sampling sites located in close vicinity of the thyroid gland., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Rotigotine behenate (RGTB), a long chain alkyl ester of the prodrug of rotigotine (RGT), has been synthesized for use in a sustained delivery system. The aim of the present report was to develop and validate a simple, sensitive and reliable LC-MS/MS method for the simultaneous determination of RGT and its prodrug RGTB in rat plasma samples. Detection was performed on a 1290 Infinity UPLC coupled Triple Quad 4500 mass spectrometer operated in positive MRM mode using an Eclipse XDB-CN chromatography column (2.1mm×100mm, 3.5μm) by isocratic elution using a 0.2% formic acid aqueous solution and acetonitrile, with stable isotope labeled RGT as an internal standard. The sample preparation method employed 50μL of a plasma sample and liquid-liquid extraction with a mixture of diethyl ether-dichloromethane (3:2, v/v) as the extraction solvent. The proposed method was fully validated by assessing its specificity, linearity, precision and accuracy, recovery, matrix effects and stability. Good linearity was found within the range of 0.1-10.0ng/mL for both analytes (r>0.996). This method was successfully applied to a pharmacokinetic study of a slow release RGTB formulation in rats following a single intramuscular injection and biological conversion in vitro., (Copyright © 2017. Published by Elsevier B.V.)

A novel ultra-high-pressure liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of the dopamine receptor agonist rotigotine in human plasma. Following liquid-liquid extraction with tert-butyl methyl ether from 500 μL plasma, the chromatographic analysis was performed on a Gemini NX3 column using 5 mm pH 5.0 ammonium acetate-5 mm ammonium acetate in methanol as binary gradient mobile phase, at a flow rate of 0.3 mL/min. The MS/MS ion transitions were 316.00 → 147.00 for rotigotine and 256.10 → 211.00 for the internal standard (lamotrigine). The lower limit of quantitation was 50 pg/mL and the linearity was determined from 50 to 2500 pg/mL. The mean recovery was 96.9%. Both intra- and interassay imprecision and inaccuracy were ≤15% at all quality control concentrations. The method was successfully applied to measure morning trough plasma rotigotine concentrations in a series of patients with Parkinson's disease on chronic treatment. The present study describes the first fully validated method for rotigotine determination in human plasma., (Copyright © 2017 John Wiley & Sons, Ltd.)

The direct analysis of drug distribution of rotigotine-loaded microspheres (RoMS) from tissue sections by liquid extraction surface analysis (LESA) coupled with tandem mass spectrometry (MS/MS) was demonstrated. The RoMS distribution in rat tissues assessed by the ambient LESA-MS/MS approach without extensive or tedious sample pretreatment was compared with that obtained by a conventional liquid chromatography tandem mass spectrometry (LC-MS/MS) method in which organ excision and subsequent solvent extraction were commonly employed before analysis. Results obtained from the two were well correlated for a majority of the organs, such as muscle, liver, stomach, and hippocampus. The distribution of RoMS in the brain, however, was found to be mainly focused in the hippocampus and striatum regions as shown by the LESA-imaged profiles. The LESA approach we developed is sensitive enough, with an estimated LLOQ at 0.05 ng/mL of rotigotine in brain tissue, and information-rich with minimal sample preparation, suitable, and promising in assisting the development of new drug delivery systems for controlled drug release and protection. Graphical abstract Workflow for the LESA-MS/MS imaging of brain tissue section after intramuscular RoMS administration.

Raltitrexed is a thymidylate synthase inhibitor that can be administered safely to patients with cardiovascular disease or dihydropyrimidine dehydrogenase deficiency, as opposed to 5FU. The recommended dose of 3mg/m 2 every 3 weeks often leads to toxicity. Interestingly, the 2mg/m 2 every 2 weeks dose appears to be less toxic. A pharmacokinetic trial was then performed by our team to investigate such phenomenon. However, there are currently, two main methods for RTX measurement described in the literature: a radioimmunoassay (RIA) and chromatographic-based methods with either UV or mass spectrometry detections. The RIA methods: display a low limit of quantification (below 1μg/L), but also a low extent of linearity for the calibration curve. The chromatographic-based methods: include high level of calibrators, but have poor sensitivity (>2μg/mL). If a high sensitivity is essential to satisfactorily describe the elimination of RTX, high concentrations in the calibration curve are also needed to avoid bias linked to the dilutions of the samples. A new LC-MS/MS method was then developed that allows to simultaneously measure very low (0.1μg/L) and very high (3000μg/L) concentrations in the same run. Moreover, the extraction steps are very simple and fast with mainly a precipitation and a filtration steps. This method was validated following the EMA recommendations. In view of the extent of the calibration curve, the carry-over effect was more deeply investigated. With this method, it was possible to measure RTX in samples taken 3 weeks after the administration. Taken together, this method allows to simply and quickly measure RTX in plasma of patients., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated pathogenesis and targeting gluconeogenesis inhibition is a promising strategy for anti-diabetic drug discovery. G protein-coupled receptors (GPCRs) are classified as distinct families by heterotrimeric G proteins, primarily including Gαs, Gαi and Gαq. Gαs-coupled GPCRs function potently in the regulation of hepatic gluconeogenesis by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway and Gαi-coupled GPCRs exhibit inhibitory effect on adenylyl cyclase and reduce intracellular cAMP level. However, little is known about the regulation of Gαq-coupled GPCRs in hepatic gluconeogenesis. Here, small-molecule 2-(2,4-dimethoxy-3-methylphenyl)-7-(thiophen-2-yl)-9-(trifluoromethyl)-2,3-dihydropyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4( 1H )-one (DMT) was determined to suppress hepatic glucose production and reduce mRNA levels of gluconeogenic genes. Treatment of DMT in db/db mice decreased fasting blood glucose and hemoglobin A1C (HbA1c) levels, while improved glucose tolerance and pyruvate tolerance. Mechanism study demonstrated that DMT-inhibited gluconeogenesis by regulating the Gαq/phospholipase C (PLC)/inositol-1,4,5-triphosphate receptor (IP3R)-mediated calcium (Ca 2+ )/calmodulin (CaM)/phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT)/forkhead box protein O1 (FOXO1) signaling pathway. To our knowledge, DMT might be the first reported small molecule able to suppress hepatic gluconeogenesis by regulating Gαq signaling, and our current work has also highlighted the potential of DMT in the treatment of T2DM., (© 2017 Society for Endocrinology.)

Introduction: Homocysteine increase and glutathione derivative cysteinyl-glycine fall are indirect biomarkers for oxidative stress, for instance due to dopamine D 1 receptor stimulation., Objectives: To investigate the influence of the D 1 receptor agonists levodopa and rotigotine compared with placebo on homocysteine and cysteinyl-glycine in plasma of patients with Parkinson's disease., Methods: Patients received 100 mg levodopa, 4 mg rotigotine or placebo. Cysteinyl-glycine and homocysteine were measured every 30 min over three hours., Results: Homocysteine rose during levodopa- and placebo administration. Rotigotine had no effect. Cysteine-glycine only increased after placebo- but not after levodopa- or rotigotine., Discussion: Homocysteine elevation results from hepatic and gastrointestinal methylation processes. Transdermal rotigotine circumvents these methylation locations. Turnover of segregated alkyl residuals from rotigotine serves as methyl group donors, which counteract homocysteine increment. The placebo-related cysteinyl-glycine increase results from reduced free radical exposure. Low levodopa dosing and antioxidants in the rotigotine patch matrix prevented cysteinyl-glycine fall.

Ammuxetine (AMT), a novel chiral antidepressant candidate compound, exhibits better antidepression effects than duloxetine in different animal models. In this article, a chiral derivatization method, combined with online solid phase extraction (online SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed for the chiral separation of AMT enantiomers after administration of racemic AMT to dogs. The derivatization reaction employed 2,3,4,6-tetra-O-acetyl-b-glucopyr-anosyl isothiocyanate (GITC) as a precolumn chiral derivatization reagent. A SPE column Retain PEP Javelin (10 × 2.1 mm) was used to remove proteins and other impurities in plasma samples. The enantiomeric derivatives were separated on a ZORBAX SB-C 18 column (50 × 2.1 mm × 3.5 μm) with an isocratic elution procedure. The selected multiple reaction monitoring mode of the positive ion was performed and the parent to the product transitions m/z 681.0/543.1 and m/z 687.4/543.1 were used to measure the derivatives of AMT and duloxetine (internal standard) with electrospray ionization. The method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability. The method was applied to a pharmacokinetics study of AMT racemate in dogs. The results suggested that the pharmacokinetic of AMT enantiomers might be stereoselective in dogs., (© 2017 Wiley Periodicals, Inc.)

The free fatty acid receptor GPR40 is predominantly expressed in pancreatic β-cells and enhances insulin secretion in a glucose dependent manner. Therefore, GPR40 agonists are possible novel insulin secretagogues with reduced or no risk of hypoglycemia for the treatment of type 2 diabetes mellitus (T2DM). Chemically and structurally diverse GPR40 agonists with high safety are pursued for the clinical development of GPR40-based pharmacotherapeutics. Herein we report our design and discovery of a new chemotype of GPR40 agonists free of the typical phenylpropanoic acid scaffold. The thiophen-2-ylpropanoic acid containing GPR40 modulators functioned as full agonists with high-efficacy response (E max ) and reduced lipophilicity. Significantly, the lead compound in this series, (R)-7k, exhibited more potent in vitro glucose-stimulated insulin secretion and in vivo glucose-lowering effects (10 mg/kg, po) than the GPR40 partial agonist TAK-875, which was once in phase III clinical trials, and high selectivity over the relevant receptors GPR120 and PPARγ.

A sensitive and precise method is described for the simultaneous determination of two small molecule kinase inhibitors: MK-1775 (MK) and AZD-7762 (AZD), in acetonitrile (ACN)-aqueous solution and in mouse plasma. A Nova-Pak C18 reversed phase column (3.9mm×150mm, 4μm, 60Å) was utilized in the separation using an isocratic mobile phase of 0.1% v/v triethylamine in phosphate buffer (pH=7.4): acetonitrile (ACN) (60:40, v/v), at a flow rate of 0.8mL/min. Detection wavelength was set at 310nm for both MK and AZD, and 431nm for the internal standard sunitinib (SUN). The developed method was validated following the ICH guidelines and it was shown to be accurate, precise and linear in the range of 41ng/mL to 8333ng/mL for both drugs in the ACN-aqueous solution and from 83ng/mL to 8333ng/mL for both drugs in mouse plasma samples. For the first time, the presented data suggest the suitability of this method for the simultaneous separation and quantification of MK and AZD in both ACN aqueous solution as well as in mouse plasma samples., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Use of methiopropamine (MPA), a synthetic metamfetamine analog, has been detected since 2011 in Europe, but there is limited information on its acute toxicity. A 30-year-old man was admitted to the emergency department in a confused state, with paranoid delusion, auditory and visual hallucinatory experiences, and incoherent speech following the use of "synthacaine" (a slang term derived from "synthetic" and "cocaine"). Toxicological screening for pharmaceuticals and drugs of abuse by liquid chromatography-diode-array detector, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS-MS) detected MPA, which was subsequently quantified by a specific LC-MS-MS method. Of note, 13 h after presentation to the emergency department, the plasma concentration of MPA was 14 ng/mL. This case report confirms the toxicity of MPA and the need for toxicological analysis to confirm the substance actually ingested by users of new psychoactive substances., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The present investigation is aimed to design a statistically optimized self-microemulsifying drug delivery system (SMEDDS) of eprosartan mesylate (EM). Preliminary screening was carried out to find a suitable combination of various excipients for the formulation. A 3(2) full factorial design was employed to determine the effect of various independent variables on dependent (response) variables. The independent variables studied in the present work were concentration of oil (X 1) and the ratio of S mix (X 2), whereas the dependent variables were emulsification time (s), globule size (nm), polydispersity index (pdi), and zeta potential (mV), and the multiple linear regression analysis (MLRA) was employed to understand the influence of independent variables on dependent variables. Furthermore, a numerical optimization technique using the desirability function was used to develop a new optimized formulation with desired values of dependent variables. The optimized SMEDDS formulation of eprosartan mesylate (EMF-O) by the above method exhibited emulsification time, 118.45 ± 1.64 s; globule size, 196.81 ± 1.29 nm; zeta potential, -9.34 ± 1.2 mV, and polydispersity index, 0.354 ± 0.02. For the in vitro dissolution study, the optimized formulation (EMF-O) and pure drug were separately entrapped in the dialysis bag, and the study indicated higher release of the drug from EMF-O. In vivo pharmacokinetic studies in Wistar rats using PK solver software revealed 2.1-fold increment in oral bioavailability of EM from EMF-O, when compared with plain suspension of pure drug.

There is a relationship between circadian rhythm and metabolic disorders. The active agent, SR8278, could competitively bind to and inhibit the nuclear receptor, Rev-erb (a major modulator of mammalian circadian clock system), to regulate the metabolism in organisms. However, we had limited knowledge of the pharmacokinetic (PK) characteristics of SR8278. Here, we describe a sensitive and reproducible ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method to quantify SR8278 in vivo. The linearity range and the limit of quantification (LOQ) for SR8278 were 30-3000 ng/mL and 6 ng/mL, respectively. The inter-day and intra-day variability were within 10%. This UPLC-MS/MS method was successfully used to characterize the PK behaviors of SR8278 in normal and diabetic rats after intravenous (i.v.) injection at a dosage of 2mg/kg. No significant differences were observed in the PK parameters of SR8278 in normal and diabetic rats. Specifically, the values of areas under plasma concentration time curves (AUC), initial plasma concentrations (C0), elimination half-lives (t1/2), and clearances (CL) were 608.33 ± 295.25 vs. 598.59 ± 276.92 ng·h/mL, 2410.25 ± 202.36 vs. 3742.11 ± 1300.21 ng/mL, 0.17 ± 0.08 vs. 0.11 ± 0.04 h, 3330.83 ± 1609.48 vs. 3364.81 ± 1111.38 mL/kg·h for SR8278 in normal rats vs. diabetic rats, respectively. In conclusion, a UPLC-MS/MS method was successfully developed and validated for the first time, with a wide linearity range, low LOQ, small sample volume (10 μL), rapid analysis (4 min) and excellent recoveries (>80%). It was also used to clarify the PK characteristics of SR8378 in rats. The same PK behaviors of SR8278 in normal and diabetic rats showed that diabetes may have little or no effect on the disposition, metabolism and/or elimination in vivo, which may be of great importance for future clinical studies., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background and Purpose: The tachykinin NK2 receptor antagonist ibodutant is under Phase III clinical investigation to treat female patients with irritable bowel syndrome. The aim of this study was to investigate the NK2 receptor-related gender specificity in a model of colitis., Experimental Approach: Colitis was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS, 0.5 mL, 30 mg·mL(-1) in 30% ethanol) in female and male guinea pigs. Electromyographic recording of the responses to colorectal distension (CRD) was made 3 days later. Ibodutant (0.33 , 0.65, 1.9 and 6.5 mg·kg(-1) ) was given s.c., 30 min before CRD. Release of neurokinin A and substance P from isolated mucosal and smooth muscle tissues following treatment with KCl (80 mM) or capsaicin (10 μM) was measured by EIA. Plasma pharmacokinetics of ibodutant following a single s.c. administration (0.73 or 2.1 mg·kg(-1) ) were measured over 24 h., Key Results: Ibodutant did not affect abdominal contractions in control animals. After TNBS-induced colitis, ibodutant prevented the increased visceral hypersensitivity to CRD in females, at lower doses than in males. Ibodutant pharmacokinetics did not differ between females and males. Tachykinins release was greater in smooth muscle than in mucosal samples. Capsaicin-stimulated release of tachykinins from inflamed mucosal samples from females was significantly lower than in males., Conclusions and Implications: Ibodutant prevented abdominal nociception in a model of visceral hypersensitivity in guinea pigs with a greater efficacy in females than in males. Our results highlight a gender-related difference in colonic visceral hypersensitivity and mucosal nerve activation., (© 2016 The British Pharmacological Society.)

Objectives: Methiopropamine (MPA; 1-(thiophen-2-yl)-2-methylaminopropane) belongs to the new psychoactive substances (NPS) that have emerged on the drug market in recent years. MPA appeared in 2011 and is an analogue of methamphetamine, sold as, for example, "Slush Eric" and "Blow." It is reported to have effects similar to those of methamphetamine, but the toxicity in humans is not known. Three fatal cases involving MPA have been reported. One analytical confirmed intoxication case has been published, and this supports the symptoms described by the users. The prevalence of recreational use of MPA is unknown, and no studies have reported the prevalence in driving under the influence of drug (DUID) cases., Methods: We investigated the frequency of MPA in DUID cases received at our institute during a 12-week period and report the analytical method using an ultraperformance liquid chromatography.tandem mass spectrometry for quantification of MPA in whole blood. The analytical findings were compared to the results from a clinical test of impairment performed by a physician shortly after the driving episode. The samples were analyzed for 42 different psychoactive substances., Results: MPA was detected in 10 DUID cases (0.8% of the cases), only from male drivers. Other drugs were detected concomitantly in all the cases. Two of the cases were traffic accidents., Conclusions: Our study shows that MPA is found in DUID cases and reveals that NPS are used among drivers and also proven in blood from drivers involved in traffic accidents. More studies are requested regarding the pharmacological and toxicological effects of MPA and other NPS. This is the first article that describes a method for analyzing and quantifying MPA in whole blood samples.

Background: Brexpiprazole was recently approved as adjunctive therapy for depression and treatment of schizophrenia in adults. To complement results from a previous study in which its acute effects were characterized, the present study assessed the effect of repeated brexpiprazole administration on monoaminergic systems., Methods: Brexpiprazole (1mg/kg, subcutaneous) or vehicle was administered once daily for 2 and 14 days. Single-unit electrophysiological recordings from noradrenaline neurons in the locus coeruleus, serotonin neurons in the dorsal raphe nucleus, dopaminergic neurons in the ventral tegmental area, and pyramidal neurons in the hippocampus CA3 region were obtained in adult male Sprague-Dawley rats under chloral hydrate anesthesia within 4 hours after final dosing., Results: Brexpiprazole blunted D2 autoreceptor responsiveness, while firing activity of ventral tegmental area dopaminergic neurons remained unaltered. Brexpiprazole increased the firing rate of locus coeruleus noradrenaline neurons and increased noradrenaline tone on α2-adrenergic receptors in the hippocampus. Administration of brexpiprazole for 2 but not 14 days increased the firing rate of serotonin neurons in the dorsal raphe nucleus. In the hippocampus, serotonin1A receptor blockade significantly disinhibited pyramidal neurons after 2- and 14-day brexpiprazole administration. In contrast, no significant disinhibition occurred after 24-hour washout or acute brexpiprazole., Conclusions: Repeated brexpiprazole administration resulted in a marked occupancy of D2 autoreceptors, while discharge activity of ventral tegmental area dopaminergic neurons remained unaltered. Brexpiprazole enhanced serotonergic and noradrenergic tone in the hippocampus, effects common to antidepressant agents. Together, these results provide further insight in the neural mechanisms by which brexpiprazole exerts antidepressant and antipsychotic effects., (© The Author 2015. Published by Oxford University Press on behalf of CINP.)

Ipragliflozin is a highly potent and selective sodium-dependent glucose co-transporter-2 (SGLT2) inhibitor, a novel class of hypoglycemic agents. The aim of the present study was to establish a new highly sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative analysis of ipragliflozin in rat plasma and apply this method to a pharmacokinetic study in rats. Empagliflozin was used as an internal standard (I.S.) and liquid-liquid extraction was conducted using tert-butyl methyl ether. Chromatographic separation was accomplished on a Quicksorb ODS (2.1mm i.d.×150mm, 5μm in size) with acetonitrile/0.1% formic acid (90:10, v/v) at a flow rate of 0.2mL/min. An API 3200 triple quadrupole mass spectrometer operating in the positive electrospray ionization mode with multiple reaction monitoring was used to detect ipragliflozin and I.S. transitions: m/z 422.0 [M+NH4](+)→151.0 for ipragliflozin and m/z 451.2 [M+H](+)→71.0 for I.S. Inter- and intra-day accuracies and precisions were within ±15%. This validated method was successfully applied to a pharmacokinetic study of ipragliflozin in rats. This assay method may contribute to assessment of novel SGLT2 inhibitors using the rat as an animal model., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Methiopropamine (1-(thiophen-2-yl)-2-methylaminopropane) is a synthetic methamphetamine analogue and is classified as a novel psychoactive substance. The use of novel psychoactive substance has been increasing substantially for recreational purpose in recent years. Methiopropamine was first detected in 2011 in Finland and was later detected in the United Kingdom. It can be purchased on the Internet and is currently poorly regulated. Reported adverse effects of methiopropamine use are mostly anecdotal user reports on Internet forums, and there are limited data on its pharmacodynamics and toxicity in the literature. Death as a direct result from methiopropamine toxicity has not been reported in Australia. We report here the first case of death caused by recreational use of methiopropamine in Australia. This same incident highlights the first ever death from isolated methiopropamine use. Being an analogue of methamphetamine, we hypothesize that the mechanism of death caused by methiopropamine would not be dissimilar to methamphetamine.

Background: Use of vitamin K antagonists for the prevention of stroke and systemic embolism in dialysis patients with nonvalvular atrial fibrillation is controversial. However, no good alternatives presently are available. The anti-factor Xa antagonist rivaroxaban is contraindicated for lack of pharmacokinetic, pharmacodynamic, and clinical data. This study aims to characterize the pharmacokinetics/pharmacodynamics of rivaroxaban in maintenance hemodialysis patients., Study Design: Pharmacokinetic and pharmacodynamic study., Setting & Participants: 18 maintenance hemodialysis patients without residual kidney function at 2 centers. DRUG ADMINISTRATION, OUTCOMES, & MEASUREMENTS: (1) A single dose of 10mg of rivaroxaban was administered at the end of each of 3 consecutive dialysis sessions and area under the curve (AUC) and the effect on coagulation parameters were measured for 44 hours thereafter. (2) A single dose of 10mg of rivaroxaban was given 6 to 8 hours before a dialysis session and the effect of dialysis on rivaroxaban concentrations was evaluated. (3) To assess potential accumulation, 10mg of rivaroxaban was given once daily and AUC was measured during 24 hours on days 1 and 7., Results: Mean AUC0-44 of rivaroxaban plasma concentrations after a single dose of 10mg was 2,072μg/L/h, mean maximum concentration was 172.6μg/L, and mean terminal elimination half-life was 8.6 hours. Dialysis had no appreciable effect on rivaroxaban plasma concentrations. Mean trough concentration after multiple daily doses of 10mg was 20.2μg/L., Limitations: Higher rivaroxaban doses and patients with substantial residual kidney function were not studied., Conclusions: A 10-mg dose of rivaroxaban in hemodialysis patients without residual kidney function results in drug exposure similar as published for 20mg in healthy volunteers. Rivaroxaban is not eliminated by dialysis. There is no accumulation after multiple daily dosing. The efficacy and safety of rivaroxaban in hemodialysis patients should be the subject of a large randomized trial., (Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

A rapid, sensitive and high-throughput ultra-performance liquid chromatography method with tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of DAT-230 in rat plasma, urine, feces and tissues (heart, liver, spleen, lung, kidney, stomach, intestine and brain). The biological samples were prepared by protein precipitation, and separation was achieved on an ACQUITY™ UPLC BEH C18 column (50 mm × 2.1mm, 1.7 μm) with a mobile phase that consisted of methanol - 0.2% formic acid water (80:20, v/v) at a flow rate of 0.2 mL/min. The MS/MS ion transitions were monitored at m/z 372.17 → 357.17 for DAT-230 and m/z 406.08 → 345.16 for COH-203 (internal standard, IS). The calibration curve was linear in the range of 0.1-5200 ng/mL for all biological matrices (r(2) ≥ 0.996), and it had the same value for the lower limit of quantification. The validated method was successfully applied to the pharmacokinetics, tissue distribution and excretion study after intravenous administration of a 5mg/kg dose of DAT-230 to healthy Sprague-Dawley rats. The mean pharmacokinetic parameters of t1/2 and AUC0-12 were (1.1 ± 0.4)h and (861.0 ± 281.2) ng h/mL, respectively. Tissue distribution results indicated that DAT-230 exhibited rapid distribution and high liver, kidney, spleen, stomach and intestine uptake; these organs were indicated as the major target organs of the drug. In total, 5.3% of the administered DAT-230 was excreted in an unconverted form in urine, feces and bile, which implies that DAT-230 was excreted primarily in the form of metabolites., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Aims: Assess the steady-state pharmacokinetics, pharmacodynamics and safety of once-daily (q.d.) versus twice-daily (b.i.d.) dosing with canagliflozin at the same total daily doses of 100 and 300 mg in healthy participants., Methods: 34 participants (17 in each cohort) were enrolled in this single-center, open-label, multiple-dose, 2-cohort, 2-way crossover study. Participants in each cohort received a total daily dose of either 100 or 300 mg canagliflozin for 5 days with q.d. then b.i.d. dosing or vice versa. Pharmacokinetics and pharmacodynamics were assessed on day 5 of each period., Results: The canagliflozin Cmax,ss of 100 and 300 mg q.d. dosing were higher by 66% and 72% than corresponding morning Cmax,ss of the 50 mg and 150 mg b.i.d. regimen, respectively. The geometric mean ratios (90% CI) of b.i.d./q.d. for AUC0-24h,ss at total doses of 100 and 300 mg were 97.08 (94.08; 99.62) and 99.32 (94.71; 104.16) respectively. Median tmax and mean t1/2 were independent of dose and regimen. Mean (SE) 24-h mean renal glucose threshold values for b.i.d. and q.d. regimens were 59.2 (1.03) and 60.2 (1.03) mg/dL for the 100 mg daily doses and 51.0 (1.04) and 52.5 (1.04) mg/dL for the 300 mg daily doses. Mean (SE) values of 24-h urinary glucose excretion for b.i.d. and q.d. regimens were 52.8 (1.94) and 48.6 (1.94) g for the 100 mg daily doses and 58.6 (3.81) and 57.8 (3.81) g for the 300 mg daily doses. Both doses were safe and well tolerated., Conclusion: Pharmacokinetics and pharmacodynamics of canagliflozin administered q.d. relative to b.i.d. at the same 100 and 300 mg total daily doses were comparable. Overall, canagliflozin was well tolerated.

GDC-0834, a Bruton's tyrosine kinase inhibitor investigated as a potential treatment of rheumatoid arthritis, was previously reported to be extensively metabolized by amide hydrolysis such that no measurable levels of this compound were detected in human circulation after oral administration. In vitro studies in human liver cytosol determined that GDC-0834 (R)-N-(3-(6-(4-(1,4-dimethyl-3-oxopiperazin-2-yl)phenylamino)-4-methyl-5-oxo- 4,5-dihydropyrazin-2-yl)-2-methylphenyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-2-carboxamide) was rapidly hydrolyzed with a CLint of 0.511 ml/min per milligram of protein. Aldehyde oxidase (AO) and carboxylesterase (CES) were putatively identified as the enzymes responsible after cytosolic fractionation and mass spectrometry-proteomics analysis of the enzymatically active fractions. Results were confirmed by a series of kinetic experiments with inhibitors of AO, CES, and xanthine oxidase (XO), which implicated AO and CES, but not XO, as mediating GDC-0834 amide hydrolysis. Further supporting the interaction between GDC-0834 and AO, GDC-0834 was shown to be a potent reversible inhibitor of six known AO substrates with IC50 values ranging from 0.86 to 1.87 μM. Additionally, in silico modeling studies suggest that GDC-0834 is capable of binding in the active site of AO with the amide bond of GDC-0834 near the molybdenum cofactor (MoCo), orientated in such a way to enable potential nucleophilic attack on the carbonyl of the amide bond by the hydroxyl of MoCo. Together, the in vitro and in silico results suggest the involvement of AO in the amide hydrolysis of GDC-0834., (Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.)

Context: The clinical introduction of new oral anticoagulants (NOACs) has stimulated the development of tests to quantify the effects of these drugs and manage complications associated with their use. Until recently, the only treatment choices for the prevention of venous thromboembolism in orthopedic surgical patients, as well as for stroke and systemic embolism in patients with atrial fibrillation, were vitamin K antagonists, antiplatelet drugs, and unfractionated and low-molecular-weight heparins. With the approval of NOACs, treatment options and consequent diagnostic challenges have expanded., Objective: To study the utility of thromboelastography (TEG) in monitoring and differentiating between 2 currently approved classes of NOACs, direct thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban and apixaban)., Design: Blood samples from healthy volunteers were spiked with each NOAC in both the presence and absence of ecarin, and the effects on TEG were evaluated., Results: Both the kaolin test reaction time (R time) and the time to maximum rate of thrombus generation were prolonged versus control samples and demonstrated a dose response for apixaban (R time within the normal range) and dabigatran. The RapidTEG activated clotting time test allowed the creation of a dose-response curve for all 3 NOACs. In the presence of anti-Xa inhibitors, the ecarin test promoted significant shortening of kaolin R times to the hypercoagulable range, while in the presence of the direct thrombin inhibitor only small and dose-proportional R time shortening was observed., Conclusions: The RapidTEG activated clotting time test and the kaolin test appear to be capable of detecting and monitoring NOACs. The ecarin test may be used to differentiate between Xa inhibitors and direct thrombin inhibitors. Therefore, TEG may be a valuable tool to investigate hemostasis and the effectiveness of reversal strategies for patients receiving NOACs.