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INTRODUCTION. In the current practice of preclinical safety studies of pharmacologically active substances, standard neurotoxicity assessment procedures are mainly aimed at diagnosing higher nervous activity and behavioural disorders. However, it is the structures of the peripheral nervous system that are particularly susceptible to drug-induced neurotoxicity, which renders these structures an easy target and leads to a high incidence of neurotoxic side effects. These circumstances dictate the importance of refining methodological approaches to the assessment of toxic injury in the peripheral nervous system.AIM. The study aimed to analyse the current methodological level of clinical and functional tests for assessing the toxic effects of pharmacologically active substances on the structures of the peripheral nervous system, as well as to formulate practical recommendations for using these tests in preclinical studies in rodents.DISCUSSION. Rodents are considered the optimal test system for preclinical studies of pharmacologically active substances, but it is impossible to reproduce the entire neurological examination that is conducted to identify clinical equivalents of neurotoxicity in humans using these animals. This article presents a systematic approach to using available diagnostic tests to increase the translatability of data. The article briefly describes the neurological deficits due to adverse drug reactions in humans, as well as the main toxidromes that can also occur in animals. Based on a literature review and experience, the authors provide practical recommendations for performing basic tests to study the strength and tone of muscles, the state of physiological reflexes, the coordination of movements, and various types of sensitivities in rodents. The article provides a brief overview of the diagnostic utility of electrophysiological testing for identifying toxic damage to the peripheral nervous system. The following tests are recommended as a minimum list of primary screening techniques for detecting neurotoxic side effects in study animals: a resting posture assessment, the beam walking test, the horizontal bar test, the digit abduction score assay, the tail flick test, and the Preyer reflex test.CONCLUSIONS. The results of a comprehensive assessment of neurological deficits in rodent experiments should be analysed from a clinically relevant perspective— that is, with a focus on topical diagnosis and common pathological process components. It is advisable to verify the pathological process at the level of the peripheral nervous system using a set of electrophysiological techniques.

The coronavirus disease 2019 (COVID-19) emerged as a major global health crisis, posing significant health, economic, and social challenges. Vaccine development has been a crucial response to the severe-acute-respiratory-syndrome-related coronavirus-2 pandemic owing to the critical role of immunization in controlling infectious diseases, leading to the expedited development of several effective vaccines. Although mRNA platform-based COVID-19 vaccines authorized under emergency-use authorization have been administered globally, concerns regarding the vaccines have increased owing to the occurrence of various side effects. The present study aimed to evaluate the safety of a non-replicating recombinant baculovirus expressing the human endogenous retrovirus envelope gene (AcHERV) vaccine encoding SARS-CoV-2 antigens. Owing to the limited number of existing safety pharmacology studies on AcHERV as a viral vector vaccine, we conducted neurobehavior (Modified Irwin’s Test), body temperature, and respiratory function studies in rats and cardiovascular system studies in male beagle dogs, which were administered the AcHERV-COVID-19 vaccine using telemetry. The safety assessment revealed no significant toxicological alterations. However, in rats, both sexes administered with the AcHERV-COVID-19 vaccine exhibited a temporary increase in body temperature, which normalized or showed signs of recovery. In conclusion, AcHERV-COVID-19 demonstrates a sufficient safety profile that supports its potential evaluation in future clinical trials.

Taurine is a nonessential amino acid that has been increasingly consumed due to its various beneficial biological effects. Excessive taurine intake has been linked to the positive regulation of inflammatory responses and endoplasmic reticulum stress through the modulation of intracellular calcium levels. However, research on the potential adverse effects of taurine consumption on the respiratory system is limited. To address this, we investigated the respiratory responses of 6-week-old male Sprague-Dawley rats to taurine administered orally at 0, 100, 200, and 400 mg/kg. Respiratory rate, tidal volume, and minute volume were monitored in accordance with the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) Harmonized Tripartite Guideline S7A for Safety Pharmacology Studies for Human Pharmaceuticals. We found that taurine administration did not significantly alter respiratory rate or tidal volume; however, a significant increase in minute volume was observed 6 h after administration of 200 mg/kg taurine. [ABSTRACT FROM AUTHOR]

Background and Purpose: Drug‐induced reduction of the rapid delayed rectifier potassium current carried by the human Ether‐à‐go‐go‐Related Gene (hERG) channel is associated with increased risk of arrhythmias. Recent updates to drug safety regulatory guidelines attempt to capture each drug's hERG binding mechanism by combining in vitro assays with in silico simulations. In this study, we investigate the impact on in silico proarrhythmic risk predictions due to uncertainty in the hERG binding mechanism and physiological hERG current model. Experimental Approach: Possible pharmacological binding models were designed for the hERG channel to account for known and postulated small molecule binding mechanisms. After selecting a subset of plausible binding models for each compound through calibration to available voltage‐clamp electrophysiology data, we assessed their effects, and the effects of different physiological models, on proarrhythmic risk predictions. Key Results: For some compounds, multiple binding mechanisms can explain the same data produced under the safety testing guidelines, which results in different inferred binding rates. This can result in substantial uncertainty in the predicted torsade risk, which often spans more than one risk category. By comparison, we found that the effect of a different hERG physiological current model on risk classification was subtle. Conclusion and Implications: The approach developed in this study assesses the impact of uncertainty in hERG binding mechanisms on predictions of drug‐induced proarrhythmic risk. For some compounds, these results imply the need for additional binding data to decrease uncertainty in safety‐critical applications. [ABSTRACT FROM AUTHOR]

OBJECTIVES: During the past few decades, various compounds have been researched for their potential as radioprotectants, and many of them were found to be safe and effective in several preclinical models. However, many of these compounds were found to have serious adverse effects when evaluated in clinical settings, thereby making them unsuitable for human applications. 5-hydroxytryptophan (5-HTP) and S-(2-aminoethyl) isothiouronium bromide hydrobromide (AET) act in a synergistic fashion to promote radioprotection. The present study primarily emphasizes the safety of fixed dose of 5-HTP + AET in the lungs of C57BL/6 mice, a well-known model used in drug safety studies. MATERIALS AND METHODS: Post-administration of the combination of HTP+AET at specific time points, blood and bronchoalveolar lavage fluid (BALF) were collected for the analysis of inflammatory and oxidative stress markers of the lungs. Thereafter, the mice were sacrificed and the lungs were dissected out, weighed, and fixed in formalin for histopathological studies. RESULTS: The inflammatory biomarkers: tumor necrosis factor-alpha and interleukin-10 and oxidative stress biomarkers: 8-isoprostane and 8-hydroxy-2'-deoxyguanosine were found to have normal levels in blood and BALF in both control and treatment groups, which was further supported by normal histological findings. In addition, other endpoints such as food and water intake were found to be within normal limits. CONCLUSION: The present safety study reflects that the combination has no adverse effects on the lungs of the experimental mouse. Further, evaluation in higher mammals including nonhuman primates is essential prior to validation of the safety of the combination in humans. [ABSTRACT FROM AUTHOR]

It is strategically critical to secure pharmaceutical independence for Russia by developing the industry using the latest achievements in science and technology. The development of nationally and internationally competitive medicines calls for the harmonisation of national and international requirements for non-clinical and clinical studies.In this interview, Alexander A. Spasov, Academician of the Russian Academy of Sciences, Doctor of Medical Sciences, Full Professor, Head of the Department of Pharmacology and Bioinformatics of the Volgograd State Medical University, voices his authoritative opinion on the changes to the regulatory requirements for non-clinical and clinical studies of medicinal products that are related to the transition of the Russian Federation to the Eurasian Economic Union marketing authorisation requirements. Alexander A. Spasov touches upon the development and application potential of cutting-edge research methods (in silico, human cell-based and alternative animal-based methods) for the creation and implementation of more reliable and rapid test systems for pharmacology and toxicity studies.

Recently, there has been an increase in cannabis‐derived products being marketed as foods, dietary supplements, and other consumer products. Cannabis contains over a hundred cannabinoids, many of which have unknown physiological effects. Since there are large numbers of cannabinoids, and many are not commercially available for in vitro testing, an in silico tool (Chemotargets Clarity software) was used to predict binding between 55 cannabinoids and 4,799 biological targets (enzymes, ion channels, receptors, and transporters). This tool relied on quantitative structure activity relationships (QSAR), structural similarity, and other approaches to predict binding. From this screening, 827 cannabinoid‐target binding pairs were predicted, which included 143 unique targets. Many cannabinoids sharing core structures (cannabinoid "types") had similar binding profiles, whereas most cannabinoids containing carboxylic acid groups were similar without regards to their core structure. For some of the binding predictions (43), in vitro binding data were available, and they agreed well with in silico binding data (median fourfold difference in binding concentrations). Finally, clinical adverse effects associated with 22 predicted targets were identified from an online database (Clarivate Off‐X), providing important insights on potential human health hazards. Overall, in silico biological target predictions are a rapid means to identify potential hazards due to cannabinoid‐target interactions, and the data can be used to prioritize subsequent in vitro and in vivo testing. There has been an increase in cannabis‐derived products being marketed as consumer products. Cannabis contains over a hundred cannabinoids, many of which have unknown physiological effects. Therefore, binding between 55 cannabinoids and 4,799 biological targets (receptors, ion channels, transporters, and enzymes) was predicted using a commercial in silico tool. These in silico biological target predictions are a rapid means to identify potential hazards, and the data can be used to prioritize subsequent in vitro and in vivo testing. [ABSTRACT FROM AUTHOR]

It is imperative to develop better approaches to predict how antiarrhythmic drugs with multiple interactions and targets may alter the overall electrical and/or mechanical function of the heart. Safety Pharmacology studies have provided new insights into the multi-target effects of many different classes of drugs and have been aided by the addition of robust new in vitro and in silico technology. The primary focus of Safety Pharmacology studies has been to determine the risk profile of drugs and drug candidates by assessing their effects on repolarization of the cardiac action potential. However, for decades experimental and clinical studies have described substantial and potentially detrimental effects of Na+ channel blockers in addition to their well-known conduction slowing effects. One such side effect, associated with administration of some Na+ channel blocking drugs is negative inotropy. This reduces the pumping function of the heart, thereby resulting in hypotension. Flecainide is a well-known example of a Na+ channel blocking drug, that exhibits strong rate-dependent block of INa and may cause negative cardiac inotropy. While the phenomenon of Na+ channel suppression and resulting negative inotropy is well described, the mechanism(s) underlying this effect are not. Here, we set out to use a modeling and simulation approach to reveal plausible mechanisms that could explain the negative inotropic effect of flecainide. We utilized the Grandi-Bers model [1] of the cardiac ventricular myocyte because of its robust descriptions of ion homeostasis in order to characterize and resolve the relative effects of QRS widening, flecainide off-target effects and changes in intracellular Ca2+ and Na+ homeostasis. The results of our investigations and predictions reconcile multiple data sets and illustrate how multiple mechanisms may play a contributing role in the flecainide induced negative cardiac inotropic effect.

Many classes of drugs can induce fatal cardiac arrhythmias by disrupting the electrophysiology of cardiomyocytes. Safety guidelines thus require all new drugs to be assessed for pro-arrhythmic risk prior to conducting human trials. The standard safety protocols primarily focus on drug blockade of the delayed-rectifier potassium current (IKr). Yet the risk is better assessed using four key ion currents (IKr, ICaL, INaL, IKs). We simulated 100,000 phenotypically diverse cardiomyocytes to identify the underlying relationship between the blockade of those currents and the emergence of ectopic beats in the action potential. We call that relationship the axis of arrhythmia. It serves as a yardstick for quantifying the arrhythmogenic risk of any drug from its profile of multi-channel block alone. We tested it on 109 drugs and found that it predicted the clinical risk labels with an accuracy of 88.1–90.8%. Pharmacologists can use our method to assess the safety of novel drugs without resorting to animal testing or unwieldy computer simulations.

Aims: The aim of this study is to compare the Liverpool Causality Assessment Tool vs. Naranjo Scale for screening suspected adverse drug reaction (ADR) cases. Methods: We retrospectively reviewed patient charts with a history of suspected ADR, scored using both tools, and determined how each correlates with laboratory and other investigations. A total of 924 charts from the Clinical Pharmacology Clinic at the London Health Sciences Centre were reviewed, and 529 charts contained objective findings to support or against the diagnosis of ADR. The participant age ranged from 1 month to 93 years. We determined that the sensitivity (SN) and specificity (SP) of Liverpool and Naranjo tools for predicting ADRs with scores ranging from Possible to Definite were considered positive and Unlikely/Doubtful as negative for ADR. These results were confirmed by laboratory or clinical (re‐challenge) testing in 529 cases. Results: Liverpool causality tool had SN of 97.2 ± 2.4% and SP of 2.3 ± 1.57%. The positive (PPV) and negative predictive values (NPV) were 34.1 and 61.5%, respectively. The Naranjo Scale had SN of 81.2 ± 5.69% and SP of 13.2 ± 3.56%. PPV and NPV were 32.7 and 57.5%, respectively. Conclusion: The Liverpool Causality Assessment Tool is a more sensitive tool than the Naranjo Scale in the assessment of possible ADRs, but both tools have poor SP. The Liverpool Tool can be a useful screening tool in settings where other tests may not be readily available. However, the low PPV and NPV of both tools suggest that to pursue further testing is needed to confirm or deny an ADR. [ABSTRACT FROM AUTHOR]

Imatinib has been reported to induce heart failure and/or QTc prolongation. To better understand their underlying mechanisms, we assessed its effects on cardiohemodynamic, electrocardiographic and echocardiographic variables along with biomarkers of myocardial damage. Imatinib mesylate in doses of 1 and 10 mg/kg was intravenously administered to the halothane-anesthetized beagle dogs (n = 4). Effects of imatinib on each phase of isovolumetric contraction, ejection, isovolumetric relaxation and filling were studied, whereas its electrophysiological effects on early and late repolarization were analyzed by measuring J-Tpeak and Tpeak-Tend, respectively. The low and high doses of imatinib provided peak plasma concentrations of 3.23 and 17.39 μg/mL, reflecting clinically-relevant and supratherapeutic concentrations, respectively. Neither lethal ventricular tachyarrhythmia nor cardiohemodynamic collapse was observed. Imatinib decreased amplitude of peak −dP/dt, indicating suppression of isovolumetric relaxation, whereas no significant change was detected in the other phases. Imatinib prolonged QTc and J-Tpeakc without altering Tpeak-Tend, indicating increase of net inward current, which leads to intracellular Ca2+ overload. Thus, imatinib suppressed ventricular active relaxation and early repolarization, which may suggest the association of mitochondrial dysfunction-associated inhibition of ATP production. Since those findings were also reported for dasatinib, sunitinib and lapatinib, they could be common cardiac phenotype of tyrosine kinase inhibitors in vivo.

Medicinal properties of curcumin are widely published. Previously, researchers used curcuminoid mixture comprising three chemical forms, out of which, the highest quantity is the most active molecule—dimethoxy curcumin (DMC). Reduced bioavailability, poor aqueous solubility, and quick hydrolytic degradation of DMC have projected challenges limiting its therapeutic value. However, selective conjugation of DMC with human serum albumin (HSA) enhances drug stability and solubility by several folds. Studies using animal models demonstrated potential anti-cancer/anti-inflammatory effects of DMCHSA; both studies showed results of local administration in peritoneal cavity and rabbit knee joint. DMC has prospects as intravenous therapeutic agent because carrier is HSA. However, before in vivo testing, important preclinical data required are toxicological safety and bioavailability of soluble forms of DMC. This study evaluated absorption, distribution, metabolism, and excretion of DMCHSA. Imaging technology and molecular analysis proved bio-distribution. The study also assessed the pharmacological safety of DMCHSA in mice in terms of its acute and sub-acute toxicity, complying with regulatory toxicology. Overall, the study demonstrated the safety pharmacology of DMCHSA upon intravenous infusion. This is a novel study establishing the safety of highly soluble and stable formulation of DMCHSA, qualifying it for intravenous administration and further efficacy evaluation in suitable disease models. [ABSTRACT FROM AUTHOR]

Pulsatile hemodynamics analyses provide important information about the ventricular‐arterial system which cannot be inferred by standard blood pressure measurements. Pulse wave analysis (PWA), wave separation analysis (WSA), and wave power analysis (WPA) characterize arterial hemodynamics with limited preclinical applications. Integrating these tools into preclinical testing may enhance understanding of disease or therapeutic effects on cardiovascular function. We used a canine rapid ventricular pacing (RVP) heart failure model to: (1) Characterize hemodynamics in response to RVP and (2) assess analyses from flow waveforms synthesized from pressure compared to those derived from measured flow. Female canines (n = 7) were instrumented with thoracic aortic pressure transducers, ventricular pacing leads, and an ascending aortic flow probe. Data were collected at baseline, 1 week, and 1 month after RVP onset. RVP progressively reduced stroke volume (SV), the PWA SV estimator, and WSA and WPA pulsatility and wave reflection indices. Indices derived from synthesized flow exhibited similar directional changes and high concordance with measured flow calculations. Our data demonstrate the value of analytical hemodynamic methods to gain deeper insight into cardiovascular function in preclinical models. These approaches can provide complementary value to standard endpoints in evaluating potential effects of pharmaceutical agents intended for human use. [ABSTRACT FROM AUTHOR]

The cardiotoxicity risk of hydroxychloroquine (HCQ) and azithromycin (AZM) has been the subject of intensive research triggered by safety concerns in COVID-19 patients. HCQ and AZM have been associated with QT interval prolongation and drug-induced arrhythmias, however other cardiotoxicity mechanisms remain largely unexplored. Our group has pioneered the living heart slice preparation, an ex-vivo platform that maintains native cardiac tissue architecture and physiological electrical and contractile properties. Here, we evaluated the cardiotoxic effect of HCQ and AZM applied alone or in combination on cardiac contractility by measuring contractile force and contraction kinetics in heart slices prepared from porcine hearts.Our results show that clinically relevant concentrations of HCQ monotherapy (1-10 µM) reduced contractile force and contraction kinetics in porcine slices in a dose-dependent manner. However, AZM monotherapy decreased contractile force and contraction kinetics only at higher concentrations (30 µM).Combination ofHCQand AZM induced a dose-dependent effect similar to HCQ alone. Furthermore, pre-treating porcine heart sliceswith the L-type calcium channel agonist Bay K8644 prevented the effect of both drugs, while administration of Bay K8644 after drugs interventions largely reversed the effects, suggesting a mechanism involving inhibition of L-type calcium channels. These findings indicate that HCQ and AZM alter cardiac function beyond QT prolongation with significant contractile dysfunction in intact cardiac tissue. Our porcine heart slices provide a powerful platform to investigate mechanisms of drug cardiotoxicity. [ABSTRACT FROM AUTHOR]

Abstract Pulsatile hemodynamics analyses provide important information about the ventricular‐arterial system which cannot be inferred by standard blood pressure measurements. Pulse wave analysis (PWA), wave separation analysis (WSA), and wave power analysis (WPA) characterize arterial hemodynamics with limited preclinical applications. Integrating these tools into preclinical testing may enhance understanding of disease or therapeutic effects on cardiovascular function. We used a canine rapid ventricular pacing (RVP) heart failure model to: (1) Characterize hemodynamics in response to RVP and (2) assess analyses from flow waveforms synthesized from pressure compared to those derived from measured flow. Female canines (n = 7) were instrumented with thoracic aortic pressure transducers, ventricular pacing leads, and an ascending aortic flow probe. Data were collected at baseline, 1 week, and 1 month after RVP onset. RVP progressively reduced stroke volume (SV), the PWA SV estimator, and WSA and WPA pulsatility and wave reflection indices. Indices derived from synthesized flow exhibited similar directional changes and high concordance with measured flow calculations. Our data demonstrate the value of analytical hemodynamic methods to gain deeper insight into cardiovascular function in preclinical models. These approaches can provide complementary value to standard endpoints in evaluating potential effects of pharmaceutical agents intended for human use.

The therapeutic use of many pharmaceuticals, including small molecules and biological therapies, has been associated with the onset of psychiatric and psychological adverse events (PPAEs), posing substantial concerns to patients' health and safety. These events, which encompass mood (e.g., depression, schizophrenia, suicidal ideation) and cognitive changes (e.g., learning and memory impairment, dementia) often remain undetected until advanced stages of clinical trials or pharmacovigilance, mostly because the mechanisms underlying the onset of PPAEs remain poorly understood. In recent years, the role of neuroimmune modulation (comprising an intricate interplay between various cell types and signaling pathways) in PPAEs has garnered substantial interest. Indeed, understanding these complex interactions would substantially contribute to increase the ability to predict the potential onset of PPAEs during preclinical stages of a new drug's R&D. This review provides a comprehensive summary of the most recent advances in neuroimmune modulation-related mechanisms contributing to the onset of PPAEs and their association with specific pharmaceuticals. Reported data strongly support an association between neuroimmune modulation and the onset of PPAEs. Pharmaceuticals may target specific molecular pathways and pathway elements (e.g., cholinergic and serotonergic systems), which in turn may directly or indirectly impact the inflammatory status and the homeostasis of the brain, regulating inflammation and neuronal function. Also, modulation of the peripheral immune system by pharmaceuticals that do not permeate the blood-brain barrier (e.g., monoclonal antibodies) may alter the neuroimmunomodulatory status of the brain, leading to PPAEs. In summary, this review underscores the diverse pathways through which drugs can influence brain inflammation, shedding light on potential targeted interventions. [Display omitted] • Many pharmaceuticals may trigger Psychiatric/Psychological Adverse Events (PPAEs). • Mechanisms underlying PPAEs are mostly unknown, hampering their early detection. • Evidence supports an association between neuroimmune modulation and PPAEs. • Pharmaceuticals may directly or indirectly impact neuroimmune modulation. • Understanding the mechanisms underlying PPAEs is important when developing new drugs. [ABSTRACT FROM AUTHOR]

Assessing the magnitude of QTc prolongation is crucial in drug development due to its association with Torsades de Pointes. Inhibition of the hERG channel, pivotal in cardiac repolarization, is a key factor in evaluating this risk. In this study, the relationship between hERG inhibition and QTc prolongation magnitude was investigated, with the aim to derive simple guidance on the required hERG margin to avoid a large (>20 ms) QTc prolongation. Data from literature and FDA sources were searched for compounds with hERG IC 50 values alongside clinical QTc data with paired plasma concentrations, or compounds demonstrating a clinical concentration-QTc relationship. Relationships between hERG inhibition, hERG IC 50 margin to unbound plasma C max , and QTc prolongation magnitude were calculated. Analysis of 148 clinical QTc observations from 98 compounds revealed that compounds associated with QTc prolongation >10 ms typically exhibited hERG margins of ≤33-fold, while those exceeding 20 ms were generally associated with margins of ≤24-fold. QTc increases above 10 ms were not observed at hERG margins >100-fold. Based on 53 clinical concentration-QTc datasets, modest hERG inhibition levels of ∼ 4–6 % correlated with a 10 ms QTc prolongation, while ∼ 10–13 % inhibition corresponded to a 20 ms prolongation. This study enhances understanding of the relationship between hERG inhibition and QTc prolongation magnitude, by conducting analysis across a wide range of 98 compounds. This information can be used to determine the optimal hERG margin, particularly for drug discovery projects with limited scope to completely design-out hERG activity. • Understanding the relationship between plasma concentration, hERG inhibition and QTc prolongation is a fundamental aspect of non-clinical and clinical risk assessment. • Clinical QTc data indicates QTc prolongation >10 ms occurs at hERG margins of ≤33-fold, while QTc >20 ms was associated with margins of ≤24-fold. • QTc increases above 10 ms were not observed at hERG margins >100-fold • Modest hERG inhibition levels of 4–6 % correlated with a 10 ms QTc prolongation, while 10–13 % inhibition corresponded to a 20 ms prolongation. • This information can be used to determine the optimal hERG margin, particularly for drug discovery projects with limited scope to completely design-out hERG activity. [ABSTRACT FROM AUTHOR]

Laura Kreckler,1 Mark Osinski,1 Scott Williams,1 Roger Whiting2 1Covance Laboratories Inc., Madison, WI, 53704-2523, USA; 2Altos Therapeutics LLC, Los Altos, CA, 94022, USACorrespondence: Laura Kreckler, AbbVie, 1 North Waukegan Road, North Chicago, IL, 60064, USA, Tel +1 847 937 5744, Fax +1 847 938 3076, Email laura.kreckler@abbvie.comBackground: Gastroparesis is characterized by delayed gastric emptying in the absence of mechanical obstruction. Owing to the potential for serious side effects, current treatments have restrictions on their use and there is a need for novel compounds with favorable safety profiles. Trazpiroben (previously TAK-906) is a peripherally selective dopamine D2/D3 receptor antagonist being developed to treat chronic gastroparesis. Effects of trazpiroben on the central nervous system and pulmonary system in rats and on the cardiovascular system in dogs were assessed.Methods: Functional observational battery and locomotion assessments were conducted in groups of eight female rats receiving 0 (control), 100, 300, or 1000 mg/kg/day oral trazpiroben for 2 days. Assessments were performed at baseline (pre-dosing) and 0.5 hours post-dose on day 2 of dosing. Pulmonary safety: following administration of the same trazpiroben doses, groups of eight male rats underwent heads-out plethysmography at baseline, through 6 hours post-dose, and approximately 24 hours post-dose on day 1. Four telemetry-instrumented male beagle dogs received 0 (control), 1, 10, or 30 mg/kg of oral trazpiroben in a Latin square crossover design on days 1, 4, 8, and 11. Relevant parameters were continuously measured for approximately 18 hours post-dose.Results: No clinically meaningful effects on central nervous system, pulmonary, or cardiovascular assessments were observed at any trazpiroben dose. Significantly decreased locomotion occurred with increasing dose, including reduced horizontal/vertical ambulation at ≥ 300 mg/kg/day. Small transient decreases in systolic and pulse pressure at ≥ 10 mg/kg/day were observed, with compensatory increases in heart rate at 30 mg/kg/day. No trazpiroben-related effects on cardiovascular parameters (including QT interval corrected for heart rate) or body temperature were noted. No trazpiroben-related qualitative electrocardiogram abnormalities were observed.Discussion: Our results suggest that trazpiroben has limited central nervous system effects and a favorable cardiac safety profile.Keywords: dopamine D2/D3 selective receptor antagonist, gastroparesis, methods, safety pharmacology

This study aimed to extend the body of preclinical research on prototype dual-acting compounds combining the pharmacophores relevant for inhibiting cyclic nucleotide phosphodiesterase 10 (PDE10A) and serotonin 5-HT1A/5-HT7 receptor (5-HT1AR/5-HT7R) activity into a single chemical entity (compounds PQA-AZ4 and PQA-AZ6). After i.v. administration of PQA-AZ4 and PQA-AZ6 to rats, the brain to plasma ratio was 0.9 and 8.60, respectively. After i.g. administration, the brain to plasma ratio was 5.7 and 5.3, respectively. An antidepressant-like effect was observed for PQA-AZ6 in the forced swim test, after chronic 21-day treatment via i.p. administration with 1 mg/kg/day. Both compounds revealed an increased level of brain-derived neurotrophic factor (Bdnf) mRNA in the hippocampus and prefrontal cortex. Moreover, PQA-AZ4 and PQA-AZ6 completely reversed (+)-MK801-induced memory disturbances comparable with the potent PDE10 inhibitor, compound PQ-10. In the safety profile that included measurements of plasma glucose, triglyceride, and total cholesterol concentration, liver enzyme activity, the total antioxidant activity of serum, together with weight gain, compounds exhibited no significant activity. However, the studied compounds had different effects on human normal fibroblast cells as revealed in in vitro assay. The pharmacokinetic and biochemical results support the notion that these novel dual-acting compounds might offer a promising therapeutic tool in CNS-related disorders. [ABSTRACT FROM AUTHOR]

Adverse effects due to off-target activity can be predicted by careful comparison of the relationship between expected plasma concentration and off-target activity of the test compound with that of reference drugs targeting that receptor for their therapeutic efficacy. The ratio between plasma concentration (unbound) and the K i at the receptor is a surrogate measure reflecting receptor occupancy. Where data are available for reference drugs, we have curated and evaluated this at 100 receptors, 72 of which can involve both negative and positive modulations by drugs: a total of 172 'receptor modulations'. This provides a quantitative framework upon which to achieve consistent risk assessment of off-target interactions across receptors, across compounds and between assessors. It therefore achieves a significant departure from an opinion-based to an evidence-based approach to secondary pharmacology. Demonstration of proof-of-principle was achieved for one of the receptor interactions (α 1A -adrenoceptor antagonism leading to postural hypotension in clinical use) due to the availability of high-quality off-target K i data for >30 drugs at this receptor., Competing Interests: Declaration of competing interest All authors are or were employees of Certara UK Ltd. with the exception of LRR, KHP and HV., (Copyright © 2024. Published by Elsevier Inc.)

Intrathecal drug administration represents a promising method to deliver biologics effectively to the central nervous system (CNS). However, little is known about the tolerability and pharmacokinetics of intrathecally applied antibodies. Hence, the focus of this study was to evaluate the toxicity, pharmacokinetic, and pharmacodynamic properties of an intrathecally administered human monoclonal antibody against the growth inhibitory CNS membrane protein Nogo-A in the non-human primate (NHP). The antibody was repeatedly injected into the lumbar cerebrospinal fluid (CSF) sack of NHPs, Macaca fascicularis (N ​= ​18), at three dose levels (placebo, 75 and 150 ​mg antibody/injection, n ​= ​6/group). CSF and serum samples were collected for pharmacokinetic analysis. The health status was constantly monitored to detect any treatment-related abnormalities. After sacrifice, the CNS tissues were evaluated by immunohistochemistry and biochemistry to study the antibody distribution and target interaction in the spinal cord and brain. No treatment-related side effects were observed, and the treatment was well tolerated by NHPs. After administration, the antibody was rapidly cleared from the CSF with a half-life of 6.4 ​h and accumulated in the serum where it showed a half-life of 13.7 days. The antibody distributed over the spinal cord and brain, penetrated into the CNS parenchyma where it bound to Nogo-A expressing neurons and oligodendrocytes, and induced significant (P ​< ​0.05) downregulation of the target antigen Nogo-A. Collectively, these results support the direct administration of therapeutic antibodies into the CSF and are of relevance for the antibody-based therapeutics currently in development for different CNS diseases., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Martin Ernst Schwab reports a relationship with Novago Therapeutics AG that includes: board membership, employment, and equity or stocks. Pascal Benjamin Kunz reports a relationship with Novago Therapeutics AG that includes: employment. Michael Andreas Maurer reports a relationship with Novago Therapeutics AG that includes: employment. Jannik Vollmer reports a relationship with LYO-X AG that includes: employment. Matthias Machacek reports a relationship with LYO-X AG that includes: employment. Jelena Klisic reports a relationship with Novago Therapeutics AG that includes: employment. Oliver Weinmann reports a relationship with Novago Therapeutics AG that includes: employment. Michael Andreas Maurer has patent #WO 2021/079,002 A2 pending to NovaGo Therapeutics AG. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

COVID-19 is a potentially fatal infection caused by the SARS-CoV-2 virus. The SARS-CoV-2 3CL protease (Mpro) is a viral enzyme essential for replication and is the target for nirmatrelvir. Paxlovid (nirmatrelvir co-administered with the pharmacokinetic enhancer ritonavir) showed efficacy in COVID-19 patients at high risk of progressing to hospitalization and/or death. Nonclinical safety studies with nirmatrelvir are essential in informing benefit-risk of Paxlovid and were conducted to support clinical development. In vivo safety pharmacology assessments included a nervous system/pulmonary study in rats and a cardiovascular study in telemetered monkeys. Potential toxicities were assessed in repeat dose studies of up to 1 month in rats and monkeys. Nirmatrelvir administration (1,000 mg/kg, p.o.) to male rats produced transient increases in locomotor activity and respiratory rate but did not affect behavioral endpoints in the functional observational battery. Cardiovascular effects in monkeys were limited to transient increases in blood pressure and decreases in heart rate, observed only at the highest dose tested (75 mg/kg per dose b.i.d; p.o.). Nirmatrelvir did not prolong QTc-interval or induce arrhythmias. There were no adverse findings in repeat dose toxicity studies up to 1 month in rats (up to 1,000 mg/kg daily, p.o.) or monkeys (up to 600 mg/kg daily, p.o.). Nonadverse, reversible clinical pathology findings without clinical or microscopic correlates included prolonged coagulation times at ≥60 mg/kg in rats and increases in transaminases at 600 mg/kg in monkeys. The safety pharmacology and nonclinical toxicity profiles of nirmatrelvir support clinical development and use of Paxlovid for treatment of COVID-19. [ABSTRACT FROM AUTHOR]

Abstract Background Subtilisin QK is a serine protease in the subtilisin family, and is fermented by Bacillus subtilis QK02. The fibrinolytic activity of subtilisin QK was measured by detecting low molecular weight degradation products using a spectrophotometric method developed by Japan Bio Science Laboratory Co., Ltd. Subtilisin QK powder can maintain its fibrinolytic activity for more than 24 months when it is stored at room temperature and protected from light. Our previous results showed that subtlisin QK directly degraded cross-linked fibrins in the fibrin plate assay and effectively inhibited thrombosis in the mouse thrombus model. The aim of this study was to determine the acute toxicity, potential subchronic toxicity, and safety pharmacology of subtilisin QK in Sprague–Dawley (SD) rats. Methods In the acute toxicity study, a single oral dose of 100,000 FU/kg was administered to 10 female and 10 male SD rats. In the 28-day subchronic toxicity, 60 female and 60 male SD rats were randomly assigned to four experimental groups (daily oral dose of 0, 2500, 7500 and 25,000 FU/kg). In the safety pharmacology study, 20 female and 20 male SD rats were randomly assigned to four experimental groups (single oral dose of 0, 500, 1500 and 5000 FU/kg). Results No death occurred and no adverse effects were observed in the acute toxicity study at a dose of 100,000 FU/kg. In the 28-day subchronic toxicity study, several hematological and blood biochemical parameters showed increases or decreases; however, due to the lack of a dose–response relationship, these differences were considered unrelated to treatment. In the safety pharmacology study, no adverse effects were observed on the central nervous of SD rats post-administration up to a dose of 5000 FU/kg subtilisin QK. Conclusion The results showed that oral consumption of subtilisin QK is of low toxicological concern. No adverse effects were observed at doses of 2500, 7500, and 25,000 FU/kg in the 28-day subchronic toxicity, and the no-observed-adverse-effect level (NOAEL) of subtilisin QK was 25,000 FU/kg.

Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) have found utility for conducting in vitro drug screening and disease modelling to gain crucial insights into pharmacology or disease phenotype. However, diseases such as atrial fibrillation, affecting >33 M people worldwide, demonstrate the need for cardiac subtype-specific cells. Here, we sought to investigate the base characteristics and pharmacological differences between commercially available chamber-specific atrial or ventricular hiPSC-CMs seeded onto ultra-thin, flexible PDMS membranes to simultaneously measure contractility in a 96 multi-well format. We investigated the effects of GPCR agonists (acetylcholine and carbachol), a Ca2+ channel agonist (S-Bay K8644), an HCN channel antagonist (ivabradine) and K+ channel antagonists (4-AP and vernakalant). We observed differential effects between atrial and ventricular hiPSC-CMs on contractile properties including beat rate, beat duration, contractile force and evidence of arrhythmias at a range of concentrations. As an excerpt of the compound analysis, S-Bay K8644 treatment showed an induced concentration-dependent transient increase in beat duration of atrial hiPSC-CMs, whereas ventricular cells showed a physiological increase in beat rate over time. Carbachol treatment produced marked effects on atrial cells, such as increased beat duration alongside a decrease in beat rate over time, but only minimal effects on ventricular cardiomyocytes. In the context of this chamber-specific pharmacology, we not only add to contractile characterization of hiPSC-CMs but propose a multi-well platform for medium-throughput early compound screening. Overall, these insights illustrate the key pharmacological differences between chamber-specific cardiomyocytes and their application on a multi-well contractility platform to gain insights for in vitro cardiac liability studies and disease modelling. [ABSTRACT FROM AUTHOR]

Background and Purpose: Hydroxychloroquine, chloroquine and azithromycin are three drugs that were proposed to treat coronavirus disease 2019 (COVID‐19). While concern already existed around their proarrhythmic potential, there are little data regarding how altered physiological states encountered in patients such as febrile state, electrolyte imbalances or acidosis might change their risk profiles. Experimental Approach Potency of human ether‐à‐go‐go related gene (hERG) block was measured using high‐throughput electrophysiology in the presence of variable environmental factors. These potencies informed simulations to predict population risk profiles. Effects on cardiac repolarisation were verified in human induced pluripotent stem cell‐derived cardiomyocytes from multiple individuals. Key Results: Chloroquine and hydroxychloroquine blocked hERG with IC50 of 1.47 ± 0.07 and 3.78 ± 0.17 μM, respectively, indicating proarrhythmic risk at concentrations effective against severe acute respiratory syndrome‐coronovirus‐2 (SARS‐CoV‐2) in vitro. Hypokalaemia and hypermagnesaemia increased potency of chloroquine and hydroxychloroquine, indicating increased proarrhythmic risk. Acidosis significantly reduced potency of all drugs, whereas increased temperature decreased potency of chloroquine and hydroxychloroquine against hERG but increased potency for azithromycin. In silico simulations demonstrated that proarrhythmic risk was increased by female sex, hypokalaemia and heart failure and identified specific genetic backgrounds associated with emergence of arrhythmia. Conclusion and Implications: Our study demonstrates how proarrhythmic risk can be exacerbated by metabolic changes and pre‐existing disease. More broadly, the study acts as a blueprint for how high‐throughput in vitro screening, combined with in silico simulations, can help guide both preclinical screening and clinical management of patients in relation to drugs with potential to prolong repolarisation. [ABSTRACT FROM AUTHOR]

Animal models are essential for assessing cardiovascular responses to novel therapeutics. Cardiovascular safety liabilities represent a leading cause of drug attrition and better preclinical measurements are essential to predict drug-related toxicities. Presently, radiotelemetric approaches recording blood pressure are routinely used in preclinical in vivo haemodynamic assessments, providing valuable information on therapy-associated cardiovascular effects. Nonetheless, this technique is chiefly limited to the monitoring of blood pressure and heart rate alone. Alongside these measurements, Doppler flowmetry can provide additional information on the vasculature by simultaneously measuring changes in blood flow in multiple different regional vascular beds. However, due to the time-consuming and expensive nature of this approach, it is not widely used in the industry. Currently, analysis of waveform data obtained from telemetry and Doppler flowmetry typically examines averages or peak values of waveforms. Subtle changes in the morphology and variability of physiological waveforms have previously been shown to be early markers of toxicity and pathology. Therefore, a detailed analysis of pressure and flowmetry waveforms could enhance the understanding of toxicological mechanisms and the ability to translate these preclinical observations to clinical outcomes. In this review, we give an overview of the different approaches to monitor the effects of drugs on cardiovascular parameters (particularly regional blood flow, heart rate and blood pressure) and suggest that further development of waveform analysis could enhance our understanding of safety pharmacology, providing valuable information without increasing the number of in vivo studies needed. [ABSTRACT FROM AUTHOR]

Objective: To provide the reference resource for the safe clinical use of the compound of diphenhydramine hydrochloride and caffeine by observing its effects on the nervous system, cardiovascular system and respiratory system in experimental animals. Methods: Single dose of the compound of diphenhydramine hydrochloride and caffeine was given to animals orally. The effects on climbing ability of mice and blood pressure, electrocardiogram, respiration rate and amplitude in beagle dogs were observed and recorded. Results: With the dosage of the compound of diphenhydramine hydrochloride and caffeine (diphenhydramine hydrochloride / caffeine ratio is 1/2.4) at 51, 102, 204 mg/kg, there was no significant effect on the climbing ability in mice. With the dosages of 14.2, 28.3, 56.6 mg/kg for male Beagle dogs and 5.66, 14.2, 28.3 mg/kg for female Beagle dogs, no significant effects were observed in systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, ECG（P wave, R wave, T wave, QRS time, PR interval, QT interval), respiratory rate and amplitude. Conclusion: Under the experimental conditions, single oral dose of the compound of diphenhydramine hydrochloride and caffeine has no significant effect on the nervous system, cardiovascular system and respiratory system in experimental animals. Those results suggest that the compound of diphenhydramine hydrochloride and caffeine is a safe agent for clinical use. [ABSTRACT FROM AUTHOR]

UV-4 (N-(9-methoxynonyl)-1-deoxynojirimycin) is a broad-spectrum antiviral drug candidate with demonstrated activity in vitro and in vivo against multiple, diverse viruses. Nonclinical safety pharmacology studies were conducted to support the filing of an Investigational New Drug (IND) application. Preliminary in vitro pharmacology testing evaluating potential for binding to "off-target" receptors and enzymes indicated no significant liability for advanced development of UV-4. The safety pharmacology of UV-4 was evaluated in the in vitro human ether-à-go-go-related gene (hERG) assay, in a central nervous system (CNS) study in the mouse (modified Irwin test), in a respiratory safety study in conscious mice using whole body plethysmography, and in a cardiovascular safety study in conscious, radiotelemetry-instrumented beagle dogs. There were no observed adverse treatment-related effects following administration of UV-4 as the hydrochloride salt in the hERG potassium channel assay, on respiratory function, in the CNS study, or in the cardiovascular assessment. Treatment-related cardiovascular effect of decreased arterial pulse pressure after 50 or 200 mg of UV-4/kg was the only change outside the normal range, and all hemodynamic parameters returned to control levels by the end of the telemetry recording period. These nonclinical safety pharmacology assessments support the evaluation of this host-targeted broad-spectrum antiviral drug candidate in clinical studies. [ABSTRACT FROM AUTHOR]

• We identified the current challenges in the development of vaccines and propose revision of the guidelines for the non-clinical studies of vaccines. • The results of repeated-dose toxicity studies can be used to decide whether safety pharmacology studies are required. • The studies to evaluate toxicity due to systemic effects may not be necessary for both intramuscular and subcutaneous administration. • Women of childbearing potential could be included in clinical trials with appropriate pregnancy avoidance prior to the reproductive toxicity studies. The efficacy and safety of vaccines for the prevention of infectious diseases are mostly evaluated based on the induction of an immune response against antigens, and do not necessarily depend on the dose administered. Therefore, there are some specific aspects that need to be considered in the development of vaccines and have been described in "The Guidelines for the non-clinical studies of vaccines for the prevention of infectious disease" in Japan. Recent changes in the vaccine development field, such as the introduction of vaccines developed overseas in Japan and vaccine development on a global scale have increased the need for revision of these guidelines. In this study, we identified the current challenges in the development of vaccines through comparison of Japanese and international guidelines. We conducted a questionnaire-based survey of pharmaceutical industries in Japan, and found issues related to non-clinical studies, such as the necessity of safety pharmacology studies and repeated-dose toxicity studies for each route of administration. We examined international guidelines on these issues as well as review reports by regulatory authorities, and determined that the results of repeated-dose toxicity studies can be used to decide whether safety pharmacology studies are required, and that studies to evaluate toxicity due to systemic effects may not be necessary for both intramuscular and subcutaneous administration. We propose revision of the guidelines for the non-clinical studies of vaccines in Japan taking international harmonizaion into account. We expected that the revised guidelines will promote smooth and rational vaccine development. [ABSTRACT FROM AUTHOR]

The present safety pharmacology core battery studies (neurobehavior, respiratory, cardiovascular system, and human ether a-go-go (hERG) channel current) investigated the potential harmful effects of self-assembled-micelle inhibitory RNA-targeting amphiregulin (SAMiRNA-AREG). The SAMiRNA-AREG was administered by single intravenous injection at up to 300 mg/kg and 100 mg/kg in mice and monkeys, respectively. The hERG assay was performed in Chinese hamster ovary (CHO) cells at SAMiRNA-AREG concentrations of up to 200 μg/mL. In the evaluation on neurobehavior, a transient decrease in body temperature was found at 0.5 h (30 min) post-dose at both sexes in mice, with a single 300 mg/kg dose of SAMiRNA-AREG. However, these effects had returned to normal at 1 h post-dose. In the evaluation on hERG channel current, there were statistically significant differences in the inhibition of peak hERG potassium channel current between the 20, 100, and 200 μg/mL SAMiRNA-AREG treatment groups and the vehicle control group. However, these effects were less potent than that of E-4031, a positive control article. For the respiratory and cardiovascular systems, no treatment-related changes were observed in mice or monkeys. Thus, under these experimental conditions, these studies suggest that SAMiRNA-AREG showed no adverse effects on the neurobehavior, respiratory, and cardiovascular function.