Disproportionality analysis of reslizumab based on the FDA Adverse Event Reporting System.

Background: With the increasing prescription of reslizumab for severe asthma with an eosinophilic phenotype, a real-world pharmacovigilance analysis of reslizumab is urgently required to detect potential unreported adverse events (AEs) in clinical practice. Objectives: We aimed to provide a comprehensive evaluation of reslizumab-related AEs in the real world. Design: Disproportionality analysis based on the FDA Adverse Event Reporting System (FAERS) database. Methods: Reslizumab-related AEs between the second quarter of 2016 and the fourth quarter of 2022 from the FAERS database were obtained. A disproportionality analysis was performed to evaluate the safety profile of reslizumab using the reporting odds ratio. Results: A total of 10,450,353 reports were collected from the FAERS database. Of the 403 reslizumab-related AEs, 42 distinct AEs were identified with positive signals. The most common AEs including dyspnea and oropharyngeal pain were identified, consistent with the instruction and clinical studies. Unexpected AEs of disproportionality such as bronchospasm and chest pain were also observed. Drug ineffective was identified as a noteworthy concern that accounted for 13.90% (56/403) of the overall reslizumab-related reports. Conclusion: While reslizumab offered a promising treatment option for severe eosinophilic asthma, more attention should be paid to the common AEs and new unexpected AEs. Based on the current findings of signal detection, further prospective studies are needed for the next signal validation and confirmation.

Background: Reslizumab is a humanized monoclonal antibody that has been approved by the United States Food and Drug Administration (FDA) since 2016 for the add-on maintenance treatment of eosinophilic severe asthma. A safety profile identifies common and new unexpected adverse events (AEs) based on the data from clinical studies and post-marketing surveillance to guide informed decisions. So far, the safety profile of reslizumab has been unclear. Methods: In this study, we aimed to provide a comprehensive evaluation of reslizumab-related AEs in the real world based on the FDA Adverse Event Reporting System (FAERS) database. We analyzed the collected data using the reporting odds ratio (ROR). Results: Our study identified the most common AEs such as dyspnea and oropharyngeal pain, which were consistent with the instruction and clinical studies. We also observed unexpected AEs of disproportionality including bronchospasm and chest pain. Moreover, we identified drug ineffective as a noteworthy concern that should be addressed in future research. Conclusion: We identified new unexpected AEs in addition to the common AEs indicated in the instructions. We also emphasized the importance of correct administration protocols for reslizumab. Based on the current findings of signal detection, further prospective studies are needed for the next signal validation and confirmation.

A pharmacovigilance analysis of reslizumab.

Post-marketing safety of lorlatinib: a real-world study based on the FDA adverse event reporting system.

Background: Lorlatinib displays marked systemic and intracranial efficacy against anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC). We aimed to establish the safety profile of lorlatinib based on the Food and Drug Administration Adverse Event Reporting System (FAERS). Methods: Reports from the FAERS between 2019 and 2023 were collected to conduct the disproportionality analysis. Reporting odds ratio (ROR) was employed to detect the potential adverse events (AEs) related to lorlatinib. The clinical characteristics, age and gender differences, time to onset of AEs were also investigated. Results: A total of 2,941 AE reports were found to be associated with lorlatinib among the 8,818,870 AE reports obtained from the FAERS database. 167 lorlatinib-related AE signals were identified. The frequently reported AEs including hypercholesterolemia, oedema, and cognitive disorder were in line with those observed in clinical trials and drug instruction. However, AEs such as interstitial lung disease and AV block indicated in the drug label require further evaluation. More attention should be paid to the new potential unexpected AEs including pulmonary arterial hypertension and radiation necrosis. Furthermore, we examined the specific high-risk AEs of different ages and genders. In addition, majority of AEs occurred within the first 2 months after lorlatinib initiation with a median onset time of 51 days. Conclusion: Our study provides valuable insight into the post-marketing safety profile of lorlatinib, which can potentially benefit the rational and safe administration of lorlatinib in the clinic. Further prospective studies are needed to validate the associations between lorlatinib and the identified AEs.

A real-world disproportionality analysis of mepolizumab based on the FDA adverse event reporting system.

Background: Mepolizumab has been approved by the FDA for add-on maintenance treatment of severe asthma with an eosinophilic phenotype. Real-world studies on mepolizumab-associated adverse events are limited. The present study aimed to explore mepolizumab-related adverse events based on the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. Methods: A disproportionality analysis was performed to assess the safety profile of mepolizumab based on the reports from the FAERS database between October 2015 and December 2022. Demographic information, the time to onset, the safety of long-term mepolizumab exposure as well as safety in pediatric patients were also investigated. Results: A total of 736 significant preferred terms (PTs) were identified among the 13,497 mepolizumab-associated adverse events (AEs) reports collected from the FAERS database. The frequently reported AEs including dyspnea, fatigue, and headache were in line with drug instruction and previous studies. Unexpected significant AEs such as cough, malaise, and chest discomfort were also identified. Most AEs occurred within the first month after mepolizumab initiation. Pneumonia and wheezing were frequently reported in patients with long-term mepolizumab exposure as well as in the pediatric population. Conclusion: Our results were consistent with the observations in previous clinical and real-world studies. New and unexpected AE signals of mepolizumab were also identified. Close attention should be paid to the long-term safety of mepolizumab as well as safety in the pediatric population. Prospective studies are required for optimal use of mepolizumab.

JNK downregulation improves olanzapine-induced insulin resistance by suppressing IRS1Ser307 phosphorylation and reducing inflammation.

AIMS: c-jun N-terminal kinase (JNK) plays pivotal roles in many physiological processes, including inflammation and glucose metabolism. However, the effects of JNK on olanzapine-induced insulin resistance and the underlying mechanisms have not been fully elucidated. The aim of our study was to explore the role of JNK in olanzapine-induced insulin resistance and the underlying mechanisms. METHODS: We studied glucose metabolism in olanzapine-treated female C57B/J mice and mice with adeno-associated virus (AAV)-mediated downregulation of JNK1 in epididymal white adipose tissue (eWAT). 3T3-L1 adipocytes were used to investigate the mechanism of JNK1 regulating insulin signaling after olanzapine treatment. RESULTS: JNK was activated in eWAT after olanzapine treatment. JNK1 downregulation in eWAT ameliorated the insulin resistance and adipose tissue inflammation in olanzapine-treated mice. Furthermore, overexpression of JNK1 in adipocytes exacerbated the glucose disorder while JNK1 knockdown alleviated the impaired insulin signaling on olanzapine challenge, which was likely mediated by the reduced inflammation and insulin receptor substrate 1 (IRS1) phosphorylation. Moreover, the effect of JNK1 was attenuated by downregulation of IRS1 in adipocytes. Finally, the JNK1-IRS1 interaction and IRS1S307 phosphorylation were required for JNK1-regulated olanzapine-induced insulin resistance in adipocytes. CONCLUSIONS: Our results demonstrated that JNK1 activation by olanzapine induced insulin resistance by promoting IRS1Ser307 phosphorylation and inflammation in eWAT. These results highlighted the importance of JNK1 in eWAT as a promising drug target for olanzapine-induced insulin resistance.

Metformin ameliorates olanzapine-induced insulin resistance via suppressing macrophage infiltration and inflammatory responses in rats.

AIMS: The present study aimed to investigate the possible effects of metformin on the olanzapine-induced insulin resistance in rats. METHODS: Rats were randomly divided into three groups: the control (Control) group, the olanzapine (Ola) group and the olanzapine + metformin (Ola + Met) group. Rats in the Ola group received olanzapine (8 mg/kg/day) intraperitoneally while rats in the Ola + Met group received olanzapine (8 mg/kg/day) intraperitoneally and metformin (300 mg/kg/day) orally for 8 weeks. Rats in the Control group received vehicle accordingly. Body weight and fasting blood glucose were recorded routinely. Inflammatory cytokines TNF-α, IL-6 and IL-1ß and IL-10 were measured by ELISA. The gene expression of macrophages markers was examined by qPCR. The epididymal white adipose tissue, liver and skeletal muscle were also isolated for immunohistochemical analysis. RESULTS: Olanzapine significantly induced body weight gain and insulin resistance compared to the control, which was markedly alleviated by metformin. Pro-inflammatory cytokines TNF-α, IL-6 and IL-1ß were upregulated while the anti-inflammatory cytokine IL-10 was downregulated by olanzapine in plasma and epididymal white adipose tissue compared to the control, but not the liver and skeletal muscle. However, metformin co-administration significantly decreased the levels of TNF-α, IL-6 and IL-1ß while increased the level of IL-10 in epididymal white adipose tissue compared to olanzapine-treated rats. Moreover, olanzapine treatment markedly increased the expression of the CD68 and the M1 macrophage markers while decreased the expression of the M2 macrophage markers in epididymal white adipose tissue in rats compared to the control. However, metformin co-treatment ameliorated the effects of olanzapine. CONCLUSIONS: Our results suggest that metformin alleviated olanzapine-induced insulin resistance possibly by suppressing the inflammatory responses mediated by macrophage infiltration and polarization in epididymal white adipose tissue.

Insulin Resistance-Related Proteins Are Overexpressed in Patients and Rats Treated With Olanzapine and Are Reverted by Pueraria in the Rat Model.

BACKGROUND: Olanzapine, a commonly used second-generation antipsychotic, causes severe metabolic adverse effects, such as elevated blood glucose and insulin resistance (IR). Previous studies have proposed that overexpression of CD36, GGPPS, PTP-1B, GRK2, and adipose triglyceride lipase may contribute to the development of metabolic syndrome, and Pueraria could eliminate the metabolic adverse effects. The study aimed to investigate the association between olanzapine-associated IR and IR-related proteins (IRRPs) and determine the role of Pueraria in protection against the metabolic adverse effects of olanzapine. METHODS: The expression levels of IRRPs were examined in schizophrenia patients and rat models with long-term olanzapine treatment. The efficacy of Pueraria on anti-IR by reducing the expression of IRRPs was comprehensively evaluated. RESULTS: Our study demonstrated that in schizophrenia patients chronically treated with olanzapine, the expression levels of IRRPs in patients with a high IR index significantly increased, and these phenomena were further confirmed in a rat model. The expression levels of IRRPs were reduced significantly in Pueraria-treated IR rat models. The body weight, blood glucose, and IR index were restored to levels similar to those of normal controls. CONCLUSIONS: The IRRPs are closely related to IR induced by olanzapine, and Pueraria could interfere with olanzapine-associated IR and revert overexpressed IRRPs. These findings suggest that IRRPs are key players in olanzapine-associated IR and that Pueraria has potential as a clinical drug to prevent the metabolic adverse effects of olanzapine, further improving compliance of schizophrenia patients.

Chronic olanzapine administration causes metabolic syndrome through inflammatory cytokines in rodent models of insulin resistance.

Olanzapine is a second-generation anti-psychotic drug used to prevent neuroinflammation in patients with schizophrenia. However, the long-term administration of olanzapine leads to insulin resistance (IR); the mechanisms of this effect remains poorly understood. Using cellular and rodent models of IR induced by olanzapine, we found that chronic olanzapine treatment induces differential inflammatory cytokine reactions in peripheral adipose and the central nervous system. Long-term treatment of olanzapine caused metabolic symptoms, including IR, by markedly elevating the plasma levels of pro-inflammatory cytokines, including IL-1ß, IL-6, IL-8 and TNFα; these findings are consistent with observations from schizophrenia patients chronically treated with olanzapine. Our observations of differential inflammatory cytokine responses in white adipose tissues from the prefrontal cortex in the brain indicated cell type-specific effects of the drug. These cytokines induced IR by activating NF-kB through the suppression of IkBα. Functional blockade of the components p50/p65 of NF-kB rescued olanzapine-induced IR in NIH-3T3 L1-derived adipocytes. Our findings demonstrate that olanzapine induces inflammatory cytokine reactions in peripheral tissues without adversely affecting the central nervous system and suggest that chronic olanzapine treatment of schizophrenia patients may cause inflammation-mediated IR with minimal or no adverse effects in the brain.

Association Between First Episode Schizophrenia, Metabolic Syndrome and Insulin Resistance-Related Proteins in Female Balb/C Mice.

BACKGROUND: Metabolic syndrome is a group of different disorders mainly includes, insulin resistance, obesity, cerebrovascular disorders, dyslipidemia, which leads to increase mortality. Patients suffering from related psychotic disorders such as schizophrenia are at the higher risk of developing metabolic syndrome. The aim of this study was to evaluate the association between the first episode of schizophrenia, metabolic syndrome and insulin resistance-related proteins in blood and adipose tissue of mice. MATERIALS AND METHODS: Twelve, female Balb/c mice were randomly divided into two groups; one group was injected intraperitoneal MK-801(0.6mg/kg/d) to induce schizophrenia, and other group received the 0.9% normal saline for two weeks. Body weight, fasting blood glucose (FBG), oral glucose tolerance (OGT), and Homeostatic model assessment (HOMA), were observed. Blood and adipose tissue were collected and Western blotting was done to evaluate the insulin resistance related proteins (GGPPS, FAT, PTP-1B, GRK2, ATGL, FGF21, and PGC-1α) by using GAPDH as an internal standard. RESULTS: There was a significant increase in mean body weight in schizophrenic group (21.76 vs 22.81, P=004). On day 14, the FBG, insulin concentrations and Homeostatic model assessment and insulin resistance (HOME-IR) were high in schizhphrenic group vs control group, e.g. 5.3±0.6 vs 3.47±0.2 (P=0.0001), 28.9±2.2 vs 23.3±0.6 (P<0.005) and 9.2±1.3 vs 3.9±0.2 (P=0.0001) . Impaired glucose tolerance deranged from 4.8mmol/L to 6.4mmol/L. Western blotting showed a marked increase in the expression of GGPPS, FAT, ATGL, and FGF21 proteins in monocytes and PTP-1B, GRK2, and PGC-1α ratios in adipose tissues. CONCLUSION: There was a positive relation between schizophrenia and metabolic syndrome e.g. insulin resistance and obesity. Certain proteins in adipocytes and blood were responsible for causing insulin resistance.

Chronic Olanzapine Treatment Induces Disorders of Plasma Fatty Acid Profile in Balb/c Mice: A Potential Mechanism for Olanzapine-Induced Insulin Resistance.

BACKGROUND: Atypical antipsychotics such as olanzapine cause metabolic side effects leading to obesity and insulin resistance. The underlying mechanisms remain elusive. In this study we investigated the effects of chronic treatment of olanzapine on the fatty acid composition of plasma in mice. METHODS: Twenty 8-week female Balb/c mice were randomly assigned to two groups: the OLA group and the control group. After treatment with olanzapine (10 mg/kg/day) or vehicle intraperitoneally for 8 weeks, fasting glucose, insulin levels and oral glucose tolerance test were determined. Effects on plasma fatty acid profile and plasma indices of D5 desaturase, D6 desaturase and SCD1 activity were also investigated. RESULTS: Chronic administration of olanzapine significantly elevated fasting glucose and insulin levels, impaired glucose tolerance, but did not increase body weight. Total saturated fatty acids and n-6 polyunsaturated fatty acids were significantly increased and total monounsaturated fatty acids were significantly decreased, while total n-3 polyunsaturated fatty acids showed no prominent changes. Chronic olanzapine treatment significantly up-regulated D6 desaturase activity while down-regulating D5 desaturase activity. Palmitic acid (C16:0), dihomo-γ-linolenic acid (C20:3n-6) and D6 desaturase were associated with an increase probability of insulin resistance, whereas nervonic acid (C24:1) and SCD1 were significantly associated with a lower insulin resistance probability. CONCLUSIONS: All results indicated that such drug-induced effects on fatty acid profile in plasma were relevant for the metabolic adverse effects associated with olanzapine and possibly other antipsychotics. Further studies are needed to investigate geneticand other mechanisms to explain how plasma fatty acids regulate glucose metabolism and affect the risk of insulin resistance.

Pharmacokinetic Properties of Oral Lafutidine Tablets and the Effect of Food on its Pharmacokinetics in Healthy Chinese Subjects.

INTRODUCTION: The aim of this study was to evaluate the pharmacokinetics (PK) of single and multiple doses of oral lafutidine tablets and the effect of food on the PK properties in healthy Chinese subjects. The tolerability and the effect of gender on the PK properties were also evaluated to acquire more PK information. METHODS: Three PK studies were conducted in 12 healthy Chinese subjects (6 male, 6 female). Study 1 was a single-dose, three-period, three-dose level (10, 20, and 40 mg), three-sequence cross-over study under fasting conditions. Study 2 was a repeat-dose study (10 mg twice daily over 6 days; all 12 subjects). Study 3 was a two-period, two-sequence cross-over single-dose (10 mg) food interaction study. All randomizations (study 1, study 3) were done to ascertain 1:1 gender ratio per sequence. A validated liquid chromatography tandem mass spectrometry (LC/MS/MS) method was used to determine plasma lafutidine concentrations. PK parameters were calculated by the non-compartmental method. RESULTS: The area under the time-concentration curve (AUC) and maximum plasma concentration (C max) of lafutidine tablets were dose-independent in the single-dose study among these healthy volunteers. The PK parameters of the multiple-dose study were inconsistent with the single study. After administration of a single dose of 10 mg under either fed or fasting conditions, we found that food may not affect the degree of absorption of the lafutidine tablets, but it may slow down the absorption rate. This is shown by the fact that the AUC showed no significant difference while the peak time was significantly delayed under fed conditions. CONCLUSION: The PK of lafutidine showed dose proportionality. There was no significant accumulation of lafutidine tablets with multiple dosing. Food did not affect the degree of lafutidine absorption, but it did reduce the rate of absorption. Further study is needed regarding the effect of gender on lafutidine. Lafutidine was well tolerated within the dose range 10-40 mg, and no serious adverse events were observed.

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

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

Pharmacokinetics and Tolerability of Rufinamide Following Single and Multiple Oral Doses and Effect of Food on Pharmacokinetics in Healthy Chinese Subjects.

BACKGROUND: Rufinamide is a triazole derivative that is structurally unrelated to currently marketed antiepileptic medications for add-on treatment of seizures in the setting of Lennox-Gastaut syndrome in patients from the age of 4 years. OBJECTIVE: The purpose of this study was to determine the pharmacokinetic and safety profile of single and multiple doses of rufinamide in healthy Chinese subjects. The effects of food and gender on the pharmacokinetic properties of rufinamide were also evaluated. METHODS: In the single-dose study, volunteers were randomly assigned to 4 dose groups and received a single dose of 200, 400, 800, 1200 mg rufinamide tablets under fasting condition. Ten subjects in the 200-mg dose group were randomly assigned to either a high-fat or non-high-fat breakfast group in each study period. The drug administration was separated by a washout period of 7 calendar days. In the multiple-dose study, 10 subjects were administered on an empty stomach rufinamide 200 mg twice daily for 6 consecutive days. Liquid chromatography tandem mass spectrometry (LC-MS/MS) method was applied to determine plasma concentration of rufinamide. Pharmacokinetic parameters, including the maximum plasma concentration (C max), the time to peak concentration (t max), the area under the plasma concentration versus time curve from time 0 to the last measurable concentration (AUC0-t ) and from time 0 to infinity (AUC0-∞), terminal elimination half-life (t 1/2), apparent volume of distribution (V d), apparent clearance (CL), average residence time (MRT), area under the plasma concentration versus time curve from time 0 to the last measurable concentration at steady state (AUCss), peak concentration (C max,ss) and trough level concentration (C min,ss) at steady state were calculated using non-compartmental models. Tolerability was assessed based on investigator inquiries, spontaneous reports and clinical evaluations. RESULTS: Rufinamide displayed a dose-dependent, but sub-proportional increase in exposure following single-dose and repeated dose administration. After administration of single dose of 200, 400, 800 and 1200 mg, without food, the rufinamide mean C max (standard deviation, SD) was 1806.5 (526.4), 2490 (564.8), 3719 (976.1) and 4166 (1187.1) µg/L, respectively. Mean AUC0-t (SD) was 34,571 (9484), 56,246 (18,077), 89,022 (23,379) and 107,316 (34,766) µg·h/L, respectively. While in fed condition at the dosage of 200 mg, mean C max (SD) and mean AUC0-t (SD) were 2363 (582) µg/L and 40,593 (10,516) µg·h/L, respectively. After administration of multiple doses, arithmetic mean (SD) values of C max and AUC0-t were 3566 (873) µg/L and 62,803 (19,873) µg·h/L, respectively. The steady state was achieved by day 3 of multiple dosing after 2 daily doses (twice a day), the corresponding accumulation factor (AUCss/AUC0-t) was 0.9057. Although there were no substantial effects on exposure resulting from gender differences, a notable food effect was observed, with AUC and C max increased by 17.4 and 30.8 %, respectively. Single- and multiple-dose phases were generally safe and well tolerated. CONCLUSION: Overall, 15 % (6/40) of subjects experienced a mild indisposition with no serious adverse events. On single and multiple dosing, rufinamide exhibited nonlinear pharmacokinetics and was well tolerated in healthy Chinese subjects.

Effects of long-term smoking on the activity and mRNA expression of CYP isozymes in rats.

BACKGROUND: To investigate the effect of long-term smoking on the activity and mRNA expression of cytochrome P450 (CYP) enzymes. METHODS: Sprague-Dawley rats were exposed to passive smoking 6 cigarettes per day for 180 days. A cocktail solution which contained phenacetin (20 mg/kg), tolbutamide (5 mg/kg), chlorzoxazone (20 mg/kg) and midazolam (10 mg/kg) was given orally to rats. Blood samples were collected at pre-specified time points and the concentrations of probe drugs in plasma were determined by HPLC-MS/MS. The corresponding pharmacokinetic parameters were calculated by DAS 3.0. In addition, real-time RT-PCR was used to analyze the mRNA expression of CYP1A2, CYP2C11, CYP2E1 and CYP3A1 in rat liver. RESULTS: There were no significant influences of pharmacokinetic profiles of chlorzoxazone in long-term smoking pretreated rats. But many pharmacokinetic profiles of phenacetin, tolbutamide, and midazolam in long-term smoking pretreated rats were affected significantly (P<0.05). The results suggested that long-term smoking had significant inhibition effects on CYP2C11 and CYP3A1 while CYP1A2 enzyme activity was induced. Furthermore, Long-term smoking had no effects on rat CYP2E1. The mRNA expression results were consistent with the pharmacokinetic results. CONCLUSIONS: Alterations of CYP450 enzyme activities may fasten or slow down excretion with corresponding influence on drug efficacy or toxicity in smokers compared to nonsmokers, which may lead to clinical failures of lung cancer therapy or toxicity in smokers.

Tolerability and Pharmacokinetic Comparison of Oral, Intramuscular, and Intravenous Administration of Levosulpiride After Single and Multiple Dosing in Healthy Chinese Volunteers.

PURPOSE: The aim of this study was to characterize the pharmacokinetic (PK) properties and assess the safety profiles of different formulations of levosulpiride in healthy Chinese volunteers. METHODS: Levosulpiride was administered to 42 healthy male and female (1:1) subjects in tablet (PO) and injectable (IM and IV) dosage forms. Blood samples were collected at regular intervals after single and multiple drug administration. The concentration of levosulpiride in plasma was determined by a validated liquid chromatography tandem mass spectrometry method. Noncompartmental analysis was performed to estimate PK parameters. One-way ANOVA was used to test for linearity and assess the effect of sex on the PK properties of the drug. Adverse effects were monitored using investigators' questionnaires and subjects' spontaneous reports, vital sign measurements, hematology, clinical chemistry, and electrocardiography. FINDINGS: Levosulpiride exhibited linear pharmacokinetic properties over the dose range of 25 to 100 mg by PO route and 25 to 75 mg by IM route. The corresponding mean AUC0-t increased from 449 to 1443 ng/h/mL and from 2874 to 7559 ng/h/mL, respectively. After repeated PO and IM administration, steady state was reached on day 4 of multiple dosing with accumulation index of 1.8 and on day 2 of multiple dosing with accumulation index of 1.3, respectively. The bioavailability of levosulpiride via IM and PO routes was 96.8% and 23.4%, respectively. No significant differences were observed on PK properties between male and female subjects. More than half (23 of 42 [54.8%]) of healthy volunteers experienced one or more adverse events in total, including constipation, diarrhea, drowsiness, skin rash, and extrapyramidal reactions. IMPLICATIONS: The regimen of 50-mg levosulpiride tablets 3 times daily and 50-mg levosulpiride injection (IM) twice daily provided similar accumulation coefficient, and the former reached steady state much more slowly. The bioavailability of levosulpiride after oral administration was poor and the absorption rate was slower compared with IM administration, which imply delayed clinical efficacy for patients with dyspepsia or neuropsychiatric disorders. On multiple dosing, levosulpiride exhibited poor tolerability with high incidence of adverse reactions. There was no need to adjust administration regimen based on sex. ClinicalTrials.gov Identifier: NCT02481583.

Simultaneous determination of macitentan and its active metabolite in human plasma by liquid chromatography-tandem mass spectrometry.

Macitentan is a newly approved endothelin receptor antagonist (ERA) for the long-term treatment of PAH with superior receptor-binding properties and a longer duration of action compared to other available ERAs. However, analytical methods for simultaneous determination of macitentan and its active metabolite, ACT-132577, in human plasma have not been fully reported in the literature. In this work, a fast, sensitive, and reliable high-performance liquid chromatography-tandem mass spectrometry method (HPLC-MS/MS) was firstly developed and completely validated for simultaneous determination of macitentan and its active metabolite in human plasma. Plasma samples were processed with a protein precipitation using acetonitrile, followed by chromatographic separation using an Inertsil ODS-SP column (100×2.1mm, 3.5µm) under isocratic elution with a mobile phase consisting of acetonitrile and 0.2% formic acid at a flow rate of 0.3mL/min. Quantification was operated in multiple reaction monitoring (MRM) mode using the transitions m/z 547.1→201.0 for macitentan, m/z 589.0→203.0 for ACT-132577, and m/z 380.5→243.3 for the IS (donepezil). The assay exhibited a linear range of 1-500ng/mL for both macitentan and ACT-132577. The accuracy and the intra- and inter-precisions were within acceptable ranges and no significant matrix effect was observed during the method validation. The developed method was successfully utilized to a human pharmacokinetic study of macitentan as well as ACT-132577 after oral administration of 10mg macitentan tablet in healthy Chinese volunteers.

Pharmacokinetics and tolerability of minodronic acid tablets in healthy Chinese subjects and food and age effects on the pharmacokinetics.

PURPOSE: Minodronic acid is a third-generation bisphosphonate being developed for the treatment of osteoporosis. The aim of this study was to evaluate the pharmacokinetic profiles and tolerability of minodronic acid in healthy subjects, as well as to assess the effects of food and age on the pharmacokinetics. METHODS: This single-center, open-label, Phase I study was conducted in 4 parts. In part 1, minodronic acid tablets were administered to young volunteers at doses of 1, 2, and 4 mg. In part 2, after a single dose, young volunteers in the 1-mg dose group received repeated oral doses of minodronic acid once daily for 7 days. In part 3, a single oral dose of minodronic acid 1 mg was administered to elderly volunteers. In part 4, after a washout period of 8 days, volunteers in the 4-mg group received a single dose of 4-mg minodronic acid under fed conditions (administrated 30 minutes before a high-fat breakfast). Plasma samples were collected, and plasma concentrations of minodronic acid were analyzed by using a LC-MS/MS method. Tolerability was assessed throughout the study by physical examinations, measurement of vital signs, laboratory analyses, and monitoring of adverse events. FINDINGS: Thirty-six young volunteers (mean age, 22.1 years; mean weight, 58.6 kg) and 12 elderly volunteers (mean age, 62.3 years; mean weight, 62.4 kg) were enrolled in the study. After single doses of 1, 2, and 4 mg of minodronic acid, the dose-normalized AUC exhibited dose linearity over the range of 1 to 4 mg in the young subjects. The plasma concentration of minodronic acid reached a steady state on day 7 after oral administration once daily for 7 days, with a mean accumulation ratio of 1.3. After a single dose of minodronic acid 1 mg, plasma Cmax and AUC0-∞ were both 1.8-fold higher compared with those of the young subjects. In the 4-mg dose group, minodronic acid Cmax and AUC0-∞ were reduced by 55% and 72%, respectively, with a high-fat breakfast compared with fasted conditions. No clinically meaningful changes in vital signs, laboratory values, or ECGs were observed. IMPLICATIONS: Single dosing of minodronic acid exhibited linear pharmacokinetics over the range of 1 to 4 mg; there was no accumulation after repeated administration. Food, especially high-fat food, reduced the bioavailability of minodronic acid. In addition, the exposure of the drug was increased with age. Minodronic acid seemed to be well tolerated throughout the study. ClinicalTrials.gov Identifier: NCT02295436.

Simultaneous determination of phentermine and topiramate in human plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

A new method for simultaneous determination of phentermine and topiramate by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching modes was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. Analyses were performed on a liquid chromatography system employing a Kromasil 60-5CN column (2.1 mm × 100 mm, 5 µm) and an isocratic elution with mixed solution of acetonitrile-20mM ammonium formate containing 0.3% formic acid (40:60, v/v), at a flow rate of 0.35 mL/min. Doxazosin mesylate and pioglitazone were used as the internal standard (IS) respectively for quantification. The determination was carried out on an API 4000 triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 150.0/91.0 for phentermine, m/z 452.1/344.3 for doxazosin, and negative m/z 338.3/77.9 for topiramate, m/z 355.0/41.9 for pioglitazone. The method was validated to be linear over the concentration range of 1-800 ng mL(-1) for phentermine, 1-1000 ng mL(-1) for topiramate. Within- and between-day accuracy and precision of the validated method at three different concentration levels were within the acceptable limits of <15% at all concentrations. Blood samples were collected into heparinized tubes before and after administration. The simple and robust LC/MS/MS method was successfully applied for the simultaneous determination of phentermine and topiramate in a pharmacokinetic study in healthy male Chinese volunteers.

Pharmacokinetics and tissue distribution of clevidipine and its metabolite in dogs and rats.

The purpose of the current study was to examine the pharmacokinetic profiles and tissue distribution of clevidipine, an ultra-short-acting calcium antagonist in Beagle dogs and Sprague-Dawley rats, respectively. The pharmacokinetics and biodistribution of its primary metabolite H152/81 were also evaluated. Dogs received intravenous infusion of clevidipine at a dose rate of 17 µg/(kg·min), and rats were given intravenous administration of clevidipine at a dose of 5 mg/kg. Dog plasma and rat tissues were collected and assayed by HPLC-MS/MS. It was found that plasma clevidipine quickly reached the steady state concentration. The terminal half-life was short (16.8 min), pointing out a rapid elimination after the end of the infusion. The total clearance was 5 mL/(min·kg). In comparison, plasma concentration of H152/81 was increased more slowly and was significantly higher than that of clevidipine. After intravenous administration, clevidipine was distributed rapidly into all tissues examined, with the highest concentrations found in the brain, heart and liver. Maximal concentrations of clevidipine were found in most tissues at 10 min post-dosing. However, the proportion of clevidipine distributed in all tissues was quite small (0.042‰) compared to the total administration dose. It was suggested that clevidipine was mainly distributed in blood and it transformed to inactive metabolite rapidly.

Simultaneous determination of clevidipine and its primary metabolite in dog plasma by liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study.

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine and its primary metabolite H152/81 in dog plasma after protein precipitation with acetonitrile using felodipine as the internal standard (IS). Chromatographic separation was performed on a XB C18 column (2.1mm×50mm, 3.5µm) under isocratic conditions with the mobile phase consisting of acetonitrile and 20mM ammonium acetate buffer (pH 7.0) (40:60, v/v) at the flow rate of 0.3ml/min. The run time was 5.5min. Mass spectrometric analysis was performed on a triple quadrupole mass spectrometer operated in the multiple reaction monitoring (MRM) mode with the transitions of m/z 473.0→338.2 for clevidipine, m/z 356.1→324.0 for H152/81 and m/z 383.9→338.2 for the IS. The method was fully validated in terms of selectivity, linearity, lower limit of quantification (LLOQ), accuracy, precision, stability, matrix effect and recovery over a concentration range of 0.15-200ng/ml for clevidipine and 10-2000ng/ml for H152/81, respectively. The analytical method was applied to support a pharmacokinetic study of simultaneous determination of clevidipine and H152/81 in ten healthy beagle dogs.

Development of a liquid chromatography-tandem mass spectrometry method for determination of butoconazole nitrate in human plasma and its application to a pharmacokinetic study.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of butoconazole in human plasma. Human plasma samples of 0.2 µL were pretreated by a single step protein precipitation procedure and analyzed using a high performance liquid chromatography (HPLC) electrospray tandem mass spectrometer system. The compounds were eluted isocratically on an Inertsil ODS-SP column (100 mm×2.1 mm, 3 µm), ionized using a positive ion atmospheric pressure electrospray ionization source and analyzed using multiple reaction monitoring (MRM) mode. The ion transitions monitored were m/z 412.8→165.1 for butoconazole and m/z 453.4→230.3 for the internal standard. The chromatographic run time was 3.5 min per injection, with retention time of 2.47 min and 2.15 min for butoconazole and repaglinide, respectively. The method was validated to be linear over the range of 20 to 8000 pg/mL (r>0.999) by using a weighted (1/x(2)) quadratic regression. The mean recovery rate was more than 86.7%, and the intra- and inter-day precision of the quality control samples (QCs) was less than 8.3% and the accuracy ranged from 96.0% to 110.2%, which indicated that the quantitative method was reliable and accurate. The method is simple, rapid, and has been applied successfully to a pharmacokinetics study of butoconazole nitrate suppositories in healthy Chinese females.