Journal of pharmacological and toxicological methods最新文献

The Health and Environmental Sciences Institute (HESI) Cardiac Safety Committee designed and created a publicly accessible database with an initial set of 128 pharmacologically defined pharmaceutical agents, many with known cardiotoxic properties. The database includes specific information about each compound that could be useful in evaluating hypotheses around mechanisms of drug-induced cardiac toxicity or for development of novel cardiovascular safety assays. Data on each of the compounds was obtained from published literature and online sources (e.g., DrugBank.ca and International Union of Basic and Clinical Pharmacology (IUPHAR) / British Pharmacological Society (BPS) Guide to PHARMACOLOGY) and was curated by 10 subject matter experts. The database includes information such as compound name, pharmacological mode of action, characterized cardiac mode of action, type of cardiac toxicity, known clinical cardiac toxicity profile, animal models used to evaluate the cardiotoxicity profile, routes of administration, and toxicokinetic parameters (i.e., Cmax). Data from both nonclinical and clinical studies are included for each compound. The user-friendly web interface allows for multiple approaches to search the database and is also intended to provide a means for the submission of new data/compounds from relevant users. This will ensure that the database is constantly updated and remains current. Such a data repository will not only aid the HESI working groups in defining drugs for use in any future studies, but safety scientists can also use the database as a vehicle of support for broader cardiovascular safety studies or exploring mechanisms of toxicity associated with certain pharmacological modes of action.

The Health and Environmental Sciences Institute (HESI) is a nonprofit organization dedicated to resolving global health challenges through collaborative scientific efforts across academia, regulatory authorities and the private sector. Collaborative science across non-clinical disciplines offers an important keystone to accelerate the development of safer and more effective medicines. HESI works to address complex challenges by leveraging diverse subject-matter expertise across sectors offering access to resources, data and shared knowledge. In 2008, the HESI Cardiac Safety Committee (CSC) was established to improve public health by reducing unanticipated cardiovascular (CV)-related adverse effects from pharmaceuticals or chemicals. The committee continues to significantly impact the field of CV safety by bringing together experts from across sectors to address challenges of detecting and predicting adverse cardiac outcomes. Committee members have collaborated on the organization, management and publication of prospective studies, retrospective analyses, workshops, and symposia resulting in 38 peer reviewed manuscripts. Without this collaboration these manuscripts would not have been published. Through their work, the CSC is actively addressing challenges and opportunities in detecting potential cardiac failure modes using in vivo, in vitro and in silico models, with the aim of facilitating drug development and improving study design. By examining past successes and future prospects of the CSC, this manuscript sheds light on how the consortium's multifaceted approach not only addresses current challenges in detecting potential cardiac failure modes but also paves the way for enhanced drug development and study design methodologies. Further, exploring future opportunities and challenges will focus on improving the translational predictability of nonclinical evaluations and reducing reliance on animal research in CV safety assessments.

The principle of proportionality of the systolic area of the central aortic pressure to stroke volume (SV) has been long known. The aim of the present work was to evaluate an in silico solution derived from this principle for modelling SV (iSV model) in cardiovascular safety pharmacology studies by telemetry. Blood pressure was measured in the abdominal aorta in accordance with standard practice. Central aortic pressure was modelled from the abdominal aortic pressure waveform using the N-point moving average (NPMA) method for beat-to-beat estimation of SV. First, the iSV was compared to the SV measured by ultrasonic flowmetry in the ascending aorta (uSV) after various pharmacological challenges in beagle dogs anaesthetised with etomidate/fentanyl. The iSV showed minimal bias (0.2 mL i.e. 2%) and excellent agreement with uSV. Then, previous telemetry studies including reference vasoactive and inotropic compounds were retrospectively reanalysed to model drug effects on stroke volume (iSV), cardiac output (iCO) and systemic vascular resistance (iSVR). Among them, the examples of nicardipine and isoprenaline highlight risks of erroneous or biased estimation of drug effects from the abdominal aortic pressure due to pulse pressure amplification. Furthermore, the examples of verapamil, quinidine and moxifloxacin show that iSV, iCO and iSVR are earlier biomarkers than blood pressure itself for predicting drug effect on blood pressure. This in silico modelling approach included in vivo telemetry safety pharmacology studies can be considered as a New Approach Methodology (NAM) that provides valuable additional information and contribute to improving non-clinical translational research to the clinic.

Receptor occupancy is an indicator of antipsychotic efficacy and safety. It is desirable to simultaneously determine the occupancy of multiple brain receptors as an indicator of the efficacy and central side effects of antipsychotics because many of these drugs have binding affinities for various receptors, such as dopamine 2 (D₂), histamine 1 (H₁), and muscarinic acetylcholine (mACh) receptors. The purpose of this study was to develop a method for the simultaneous measurement of multiple receptor occupancies in the brain by the simultaneous quantification of unlabeled tracer levels using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Rats were pre-administered with a vehicle, displacer, or olanzapine, and mixed solutions of raclopride, doxepin, and 3-quinuclidinyl benzilate (3-QNB) were administered (3, 10, and 30 μg/kg). The brain tissue and plasma tracer concentrations were quantified 45 min later using LC-MS/MS, and the binding potential was calculated. The highest binding potential was observed at 3 μg/kg raclopride, 10 μg/kg doxepin, and 30 μg/kg 3-QNB. Tracer-specific binding at these optimal tracer doses in the cerebral cortex was markedly reduced by pre-administration of displacers. D₂, H_1, and mACh receptor occupancy by olanzapine increased in a dose-dependent manner, reaching 70–95%, 19–43%, and 12–45%, respectively, at an olanzapine dose range of 3–10 mg/kg. These results suggest that simultaneous determination of in vivo D₂, H₁, and mACh receptor occupancy is possible using LC-MS/MS.

To measure α-glucosidase activity, rat intestinal acetone powder is commonly used as a source of α-glucosidase, and the mutarotase-glucose oxidase (GOD) methods commonly used to quantitate glucose produced by enzymatic hydrolysis of the substrates. In this study, we compared human Caco-2 cell extracts with rat intestinal acetone powder extracts. We also compared high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) with the mutarotase-GOD method. The sensitivity of HPAE-PAD was higher than that of mutarotase-GOD. The glucose concentration quantified by HPAE-PAD was similar to that quantified using the mutarotase-GOD method. In the maltase reaction, 1-deoxynojirimycin (1-DNJ) exerted a more potent inhibitory effect on human enzymes than on rat enzymes. This order was reversed during the sucrase reaction. These results suggested that the combined use of Caco-2 cell extracts and HPAE-PAD is advantageous for use in α-glucosidase-related basic research.

Background

Several novel synthetic cannabinoids, including methyl 2-(1-(4-fluorobenzyl)-1Hindazole-3-carboxamido)-3-methylbutanoate (AMB-FUBINACA), have recently surfaced on the illicit drug market. To determine the pharmacokinetic properties (half-life, volume of distribution, and clearance) of AMB-FUBINACA in rats plasma, a straightforward, quick, and highly sensitive analytical approach was developed.

Methods

Eighteen Wistar rats were divided into two groups: one control (saline vehicle) and one treatment group (AMB-FUBINACA at 50 mg/kg). Blood samples (400 μL) were withdrawn via catheters immediately before (t = 0) and at 30, 60, 90, 120, and 240 min following injection. Samples were collected into 1 mL tuberculin syringes, then transferred to 1.5 mL plastic tubes containing 5 μL of 1000 IU/mL K3-EDTA (Thomas Scientific). Place the EDTA tubes containing samples in a centrifuge and spin at 1000 g for 10 min at 4 °C. The top layer is the plasma fraction, which is decanted into cryovials and stored at −20 °C until analysis. The gas chromatography tandem mass spectrometry (GC–MS/MS) method was optimized and validated, combined with liquid-liquid extraction, to analyze AMB-FUBINACA in rat plasma.

Results

The research method successfully met the validation requirements set by the FDA, demonstrating selectivity and linear calibration curves within a concentration range of 0.5–1000 ng/ml. The correlation coefficient (r2) was determined to be 0.99, indicating a strong linear relationship. The analyte's limit of quantitation (LOQ) was determined to be 1–5 ng/mL. Subsequently, the method was successfully applied to investigate the pharmacokinetics of AMB-FUBINACA in rats' blood samples. Following oral administration, AMB-FUBINACA was rapidly absorbed, with a plasma half-life (t1/2) of 5.91 h, a volume of distribution (Vd) of 203.13 l, and a plasma clearance of 23.81122 L/h.

Conclusion

These findings contribute to the understanding of AMB-FUBINACA's pharmacokinetics and pharmacodynamics.

Myrcene (β-myrcene), found in essential oils from plant species such as hops and cannabis, has many advantageous properties, but its use is limited due to volatility and low solubility in water. One way to circumvent these limitations is to encapsulate the essential oils in a polymer matrix. However, these hydrophobic molecules are difficult to quantify when dispersed in water. Seeking to study the release of this terpene in drug release tests from polymeric matrices, this work aimed to develop an easy and cheap UV spectrophotometric method for the quantification of β-myrcene in aqueous medium. To achieves this goal, samples were prepared in 0.05% (w/v) polysorbate 80 solution, with concentrations of β-myrcene ranging from 0.01% to 0.1% (v/v), and were analyzed at 226 nm. Each sample was analyzed in triplicate and repeated on three different days, to evaluate the repeatability of the results. The results were subjected to Q, F and Student's t-tests. The regression parameters obtained for β-myrcene were above 0.99 and through statistical analysis, it was possible to confirm the repeatability for the results. The values of the limits of detection and quantification indicated that the method is not affected by intrinsic factors of the equipment. The results of accuracy, robustness and selectivity showed recovery rates within acceptable limits. This demonstrates that the quantification of β-myrcene in aqueous medium by UV spectrophotometry is feasible.

Background and objectives

A genetic algorithm (GA) approach was developed to predict drug-drug interactions (DDIs) caused by cytochrome P450 2C8 (CYP2C8) inhibition or cytochrome P450 2B6 (CYP2B6) inhibition or induction. Nighty-eight DDIs, obtained from published in vivo studies in healthy volunteers, have been considered using the area under the plasma drug concentration–time curve (AUC) ratios (i.e., ratios of AUC of the drug substrate administered in combination with a DDI perpetrator to AUC of the drug substrate administered alone) to describe the extent of DDI.

Methods

The following parameters were estimated in this approach: the contribution ratios (CR_CYP2B6 and CR_CYP2C8, i.e., the fraction of the dose metabolized via CYP2B6 or CYP2C8, respectively) and the inhibitory or inducing potency of the perpetrator drug (IR_CYP2B6, IR_CYP2C8 and IC_CYP2B6, for inhibition of CYP2B6 and CYP2C8, and induction of CYP2B6, respectively). The workflow consisted of three main phases. First, the initial estimates of the parameters were estimated through GA. Then, the model was validated using an external validation. Finally, the parameter values were refined via a Bayesian orthogonal regression using all data.

Results

The AUC ratios of 5 substrates, 11 inhibitors and 19 inducers of CYP2B6, and the AUC ratios of 19 substrates and 23 inhibitors of CYP2C8 were successfully predicted by the developed methodology within 50–200% of observed values.

Conclusions

The approach proposed in this work may represent a useful tool for evaluating the suitable doses of a CYP2C8 or CYP2B6 substrates co-administered with perpetrators.

Introduction

Rat telemetry is the assay of choice to assess the potential effects of novel drug candidates on cardiovascular parameters during early drug discovery. Telemetry device implantation can be combined with venous catheter and access button implantation when intravenous administration of the drug substance is required.

Methods

Rats (Sprague Dawley or Han Wistar) were implanted with telemetry devices for arterial blood pressure measurement using either direct aortic catheterisation (n = 131) or aortic catheterisation via the femoral artery (n = 17). Bipolar leads for ECG recording were also implanted in some of the animals (n = 102). Femoral vein catheters and access buttons were implanted as a separate surgery after the initial telemetry implantation (n = 43).

Results

128 animals (86%) were implanted successfully with telemetry devices without any notable surgical or post-surgical problems. When considering the 2 different catheterisation methods separately, the success rate of the direct aortic approach was 88% compared to 76% with the aortic placement via the femoral artery. Lameness was the most common post-surgical problem. Blood loss during surgery and ischaemic patches on the tail were also observed at a low incidence with the direct aortic approach. Catheter pull-out occurred in some rats before the first signal check reducing the overall success rate for blood pressure measurement using the direct aortic approach to 85%. A 95% success rate was observed for catheter and access button implantation.

Discussion

A high success rate is possible when implanting telemetry devices in rats with and without venous catheters and access buttons. We have attempted to provide solutions to problems and describe refinements to the procedure which may further improve surgical outcomes.

We developed a novel, stress-free blood sampling method for minipigs, allowing continuous cortisol monitoring over 24 h. Baseline cortisol levels exhibited both ultradian and diurnal rhythms. During nighttime, smaller ultradian rhythms overlaid a lower baseline cortisol, which increased in sleeping pigs before lights were turned on. Additionally, we developed an analytical tool based on the R package “pracma” to quantify ultradian peak and circadian components of the cortisol profiles.

To validate our model, we investigated the effects of Verucerfont, a CRH receptor antagonist, and Venlafaxine, a serotonin-norepinephrine reuptake inhibitor. Verucerfont reduced cortisol levels during the first 9 h without affecting diurnal rhythm. Cortisol peak parameters decreased, with a 31% reduction in overall area under the curve (AUC) and a 38% reduction in ultradian average AUC. Ultradian peaks decreased from 7 to 4.5, with 34% lower amplitude. Venlafaxine maintained plasma concentrations within the targeted human effective range.

This method enables us to enhance our understanding of cortisol regulation and provide valuable insights for the impact of investigation drugs on the diurnal and ultradian rhythms of cortisol.