This review examines the historical development of biological warfare from premodern contamination practices to twentieth-century state programs, post-9/11 bioterrorism, and the renewed prominence of biological risk in the COVID-19 era. Drawing on historical, policy, and public-health scholarship, it shows how disease came to be understood not only as a natural threat but also as a strategic instrument shaped by scientific knowledge, military organization, and administrative secrecy. The review traces the transition from empirical uses of contamination in siege warfare and colonial settings to laboratory-based weaponization in the 20th century, including German sabotage during the First World War, Imperial Japan's Unit 731, British anthrax trials on Gruinard Island, and the expansion of United States and Soviet biological warfare programs during the Cold War. It also evaluates the limits of international restraint through the 1925 Geneva Protocol and the 1972 Biological Weapons Convention, emphasizing the persistent problem of verification illustrated by the 1979 Sverdlovsk anthrax outbreak. The analysis then follows the shift from state arsenals to public fear through Aum Shinrikyo and the 2001 anthrax letters before situating epidemic and pandemic disease within the broader politics of biological vulnerability. COVID-19 and gain-of-function research are treated as cases of intensified scrutiny of biosafety, uncertainty, and public mistrust, rather than evidence for any single-origin hypothesis. The review concludes that biological warfare is best understood not solely as the deliberate use of pathogens but as a broader political and institutional phenomenon emerging where scientific capacity, strategic fear, concealment, and social vulnerability converge.
The Expert Panel for Cosmetic Ingredient Safety (Panel) considered whether the safety of Glyceryl Isostearates and Glyceryl Stearate/Acetate as used in cosmetics should be reassessed. The Panel reviewed newly available safety data related to these ingredients. The Panel concluded, based on the available data contained in the report, that these two ingredients are safe as cosmetic ingredients in the present practices of use and concentration as described in the report.
The FDA has recently approved a medical device which determines a glomerular filtration rate assessment at the point-of-care by transdermal detection of the fluorescent tracer agent relmapirazin. Previous in vitro and in vivo studies on this agent yielded negligible safety/toxicology concern resulting in advancement to phase I, II, and III human clinical studies. Now that clinical use is occurring, herein we investigated possible interference this agent may induce with typical clinical diagnostic assays given to incoming and hospitalized patients. The testing methodology followed the CLSI EP07-A3 Interference Testing in Clinical Chemistry guideline for determination of interference. No interference from relmapirazin was detected in the suite of metabolic and cardiac assays evaluated.
Artificial intelligence (AI) and machine learning are increasingly used in toxicological risk assessment to predict chemical toxicity, identify hazardous compounds, and support regulatory decision-making. However, the widespread adoption of these models is limited by their "black-box" nature, which reduces interpretability, transparency, and regulatory confidence. Explainable artificial intelligence (XAI) has emerged as a promising approach to address these challenges by revealing how input features, including chemical structures, exposure levels, and biological pathways, contribute to toxicity predictions. Techniques such as SHAP (SHapley Additive exPlanations) and LIME (Local Interpretable Model-agnostic Explanations) provide interpretable insights into model decision-making and enhance trustworthiness, accountability, and mechanistic understanding. Despite these advances, most XAI applications in toxicology remain at the computational or preclinical stage, with limited clinical and regulatory translation. This review summarizes current AI-based approaches for toxicity prediction, examines the interpretability challenges that hinder their practical implementation, and highlights the emerging role of XAI in bridging the gap between computational prediction and clinical application. Greater standardization, integration of human data, and collaboration among academia, industry, and regulatory agencies will be essential for advancing transparent and clinically actionable toxicology models.
Novel Psychoactive Substances (NPSs) and other psychoactive or misuse-relevant compounds present a persistent global public health threat, underscoring the critical need for real-time crawling and monitoring tools to investigate and provide valuable information assisting in the management and preparedness against that dynamic and evolving threat. This study utilized the NPS finder ® web crawler to analyze NPS trends during the post-pandemic period, with data collected from selected highly trafficked psychonaut websites continuously monitored between January and September 2023. Following a comprehensive filtering process of screening, assessment, and evaluation, the dataset provided insights into the availability and characteristics of recently reported NPSs. Three hundred and sixty-eight molecules were analyzed, of which 158 were newly captured NPSs, suitable for inclusion in the NPS finder ® database. Those substances were classified based on their chemical structure, pharmacological mechanism of action, therapeutic indication, if any, and abuse liability. The main NPS classes identified were natural origin/herbal substances (25; 16%), cannabinoids (23; 15%), prescribed medications (23; 15%), synthetic opioids (20; 13%), phenethylamines (14; 9%), cathinones (11; 7%), and anabolic substances (8; 5%). The findings highlight ongoing diversification in substances identified across selected online sources during the post-pandemic period. The study benefits from a timely focus, a substantial and systematically curated dataset, and the application of a continuous web-crawling methodology enabling near real-time detection of emerging substances. The integration of pharmacological and chemical classification further enhances the interpretability and potential clinical relevance of the findings. However, results should be interpreted cautiously. The reliance on predominantly English-language, open-web sources may introduce selection bias and limit geographic generalizability, and the descriptive design does not allow inference regarding prevalence, user behavior, or causal trends. Within these constraints, web-crawling approaches may serve as valuable complementary tools to established early warning systems, supporting early signal detection and informing future toxicological and public health responses.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of Polyhydroxystearic Acid, Poly(3-Hydroxyoctanoic Acid), and Polylactic Acid as used in cosmetic formulations. These ingredients are reported to function in cosmetics as a non-surfactant dispersing agent, a skin-conditioning agent, and an abrasive agent, respectively. The Panel reviewed the available data to determine the safety of these ingredients and concluded that these ingredients are safe in cosmetics in the present practices of use and concentrations described in this safety assessment.
We identified an assay-dependent, artifactual prolongation of activated partial thromboplastin time (aPTT) during nonclinical safety studies of an enzyme biologic conjugated with a next-generation polyethylene glycol (PEG)-like stealth polymer, poly(oligoethylene glycol) methyl ether methacrylate (POEGMA), in cynomolgus monkeys. Two repeat-dose studies (8 and 13 weeks) with twice-weekly subcutaneous dosing evaluated pharmacokinetic/toxicokinetic (PK/TK) and pharmacodynamic (PD) assessments, clinical pathology, and gross/histopathology. The 8-week study used a single silica-based aPTT assay; the 13-week study used both silica-based and kaolin-based assays. In the 8-week study, the silica-based assay showed time- and dose-dependent aPTT prolongation at Weeks 4 and 8. PK/PD effects were most evident in Weeks 1-2, decreased thereafter, likely due to immunogenicity, and did not correlate with aPTT changes. Other coagulation parameters (eg, prothrombin time and fibrinogen) were unremarkable, and histopathology showed no bleeding or coagulopathy. In the 13-week study, aPTT prolongation again occurred only with the silica-based assay, whereas the kaolin-based assay showed no effect. Ex vivo aPTT testing used naïve monkey plasma spiked with either the biologic or POEGMA alone; neither component prolonged aPTT with either assay, indicating no direct interference. Collectively, these data indicate that the observed aPTT changes were assay-dependent artifacts related to the silica activator, rather than true pharmacologic or toxicologic effects. In contrast, such artifactual aPTT prolongation was not induced by the same enzyme biologic when conjugated with conventional 20-kDa PEG, indicating a POEGMA-conjugate-specific artifact.
In a 4-week rat study, a nucleotide prodrug antiviral agent containing a synthetic non-natural amino acid (C-331) induced a dose-related vacuolation in the brain's white matter tracts without concurrent neuronal loss, gliosis, or neurological deficits. Routine safety pharmacology studies showed no effects. Penetration of the drug through the blood-brain barrier was negligible. Rat-specific metabolites were not evident. A follow-up 13-week rat study with a 4-week interim assessment was performed using oral doses of 0, 100, 300, or 1000 mg/kg/day for 4 or 13 weeks. Intermittent, transient clonic convulsions (<1 min) occurred in 1 male rat at 100 mg/kg/day (3 observations) and 5 animals at 1000 mg/kg/day during the dosing phase but were not observed during recovery; their relationship to brain vacuolation remains uncertain. No test article-related neurobehavioral or open-field changes, or ophthalmic abnormalities were noted. In all treated groups, widespread vacuolation predominantly affecting white matter was observed in the cerebellum, thalamus, and striatum. The severity of vacuolation increased over time and persisted after the 4-week recovery period. Based on ultrastructural evaluation, the vacuolation resulted from myelin sheath splitting (intramyelinic edema) without axonal degeneration. The vacuolation was considered to be an adverse effect based on the severity and extent of the changes and the potential for causing oligodendrocyte dysfunction. An NOAEL in the rat was not identified. Because of multiple unknowns, including the lack of consistent neurobehavioral signs, species specificity, low exposure multiples, and the potential human significance, further development of C-331 was terminated. The study describes the unusual presentation of species-specific, drug-induced splitting of myelin sheaths/intramyelinic edema without clear correlative neurofunctional effects.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 8 Melaleuca alternifolia (tea tree)-derived ingredients as used in cosmetic formulations; 5 of these ingredients are reported to function in cosmetics as skin-conditioning agents. Because final product formulations may contain multiple botanicals, each containing the same constituents of concern, formulators are advised to be aware of these constituents and to avoid reaching levels that may be hazardous to consumers. Industry should use good manufacturing practices to minimize impurities that could be present in botanical ingredients. The Panel noted that oxidized tea tree oil could be a sensitizer, and stated that industry should employ methods to minimize oxidation of the oil in the final cosmetic product. The Panel considered all the data and concluded that these ingredients are safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-sensitizing.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 7 radish root-derived ingredients, most of which are reported to function as hair and skin conditioning agents in cosmetic products. Because final product formulations may contain multiple botanicals, each containing similar constituents of concern, formulators are advised to be aware of these constituents and to avoid reaching levels that may be hazardous to consumers. With radish root-derived ingredients, the Panel was concerned about the presence of anthocyanins and isothiocyanates in cosmetics. Industry should use current good manufacturing practices to minimize impurities that could be present in botanical ingredients. The Panel reviewed the available data and concluded that these ingredients are safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-sensitizing.
Complement-dependent cytotoxicity (CDC) is critical for tumor cell proliferation. Previous work has revealed that epalrestat (EPA), an inhibitor of aldose reductase, plays a crucial role in tumor cell proliferation. However, whether CDC is involved in EPA-mediated inhibition of cancer cell proliferation remains unclear. This study evaluates reactive oxygen species (ROS) levels, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, and Cell Counting Kit-8 assay to determine the effect of EPA on cell proliferation in colorectal cancer cells. Quantitative real-time PCR, immunoblotting, rescue experiments combined with luciferase reporter assay, and chromatin immunoprecipitation (ChIP) assay were performed to explore the mechanism of EPA on CDC. In the present study, we observed that EPA significantly downregulates cell proliferation characterized by enhanced ROS levels and reduced EdU+ positive cells, which was attributed to the decreased CD46 expression. Ectopic CD46 expression reversed the above EPA-induced phenomenon. Mechanistically, EPA treatment suppressed protein kinase D (PKD)/signal transducer and activator of transcription 3 (STAT3) phosphorylation, leading to reduce the binding ability of STAT3 to the CD46 promoter, further attenuating CD46 transactivation. Activation of PKD by phorbol 12-myristate 13-acetate largely blocked the effect of EPA-mediated CD46 transactivation. Together, the current findings revealed a novel mechanism whereby EPA modulates CDC to inhibit the proliferation of cancer cells, broadening the pharmacological functions of EPA in anti-tumor therapy.
The Expert Panel for Cosmetic Safety (Panel) assessed the safety of 8 naturally-sourced clay ingredients, of which 6 were previously reviewed, as used in cosmetic formulations. All of these ingredients are reported to function in cosmetics as absorbents and bulking agents; other cosmetic functions are also reported. The Panel reviewed all relevant data and concluded that Kaolin is safe in cosmetics in the present practices of use and concentration described in this safety assessment. The remaining 7 naturally-sourced clay ingredients are safe in cosmetics in the present practices of use and concentration, with the exception that the available data are insufficient to make a determination that these ingredients are safe in products that may be incidentally inhaled.
War and terrorism demonstrate the need for an improved antidote against nerve agents that cause brain damage following inhibition of acetylcholinesterase (AChE). Our laboratories invented substituted phenoxyalkyl pyridinium oxime AChE reactivators (US patent 9,227,937) that demonstrate the ability to cross the blood-brain barrier in in vivo rat tests with a sarin surrogate by reducing time to cessation of seizure-like behaviors, glial fibrillary acidic protein levels, and neuropathology, compared to the FDA-approved oxime, 2-pyridine aldoxime methyl chloride (2-PAM). This study investigated the safety profile of novel oximes through evaluation of their cytotoxicity and genotoxicity. Cytotoxicity was evaluated in mouse areolar fibroblasts using a lactate dehydrogenase (LDH) assay and an MTS assay. All novel oximes showed no toxicity in the LDH assay from 1.25 nM to 5 mM, whereas 2-PAM did; novel oximes were significantly different from 2-PAM (P < .00001). The MTS assay demonstrated that novel oximes at 2 µM to 500 µM significantly reduced the metabolic activity of fibroblasts compared to 2-PAM (P = .00001). A modified Ames assay using 5 bacterial strains with and without S9 assessed the genotoxicity of the lead compound, Oxime 20, at concentrations from 100 µM to 10 mM. No concentration, whether with S9 or without, showed any genotoxicity. The LDH and Ames results indicated no cytotoxicity or genotoxicity was caused by the novel oximes.
Siamenoside I, a cucurbitane glycoside 300 times sweeter than sucrose, is found in monk fruit ( Siraitia grosvenorii ). The triterpene glycosides in monk fruit, such as mogroside V, siamenoside I, and mogroside III, comprise around 1% of the fruit flesh. These mogrosides share a core structure, mogrol, with varying numbers of glucose units attached to carbon-3 of the cucurbitane backbone and/or carbon-24 of the triterpene side chain. Previous in vitro fecal homogenate metabolism and in vivo pharmacokinetic research indicated that mogrosides are deglycosylated to a common metabolite, the aglycone mogrol, by intestinal flora prior to absorption. This study was conducted using a purified siamenoside I produced via fermentation and a monk fruit extract in an in vitro human fecal homogenate system to confirm the deglycosylation of siamenoside I by intestinal microflora to the common metabolic intermediate, mogrol. The rates of deglycosylation of siamenoside I and monk fruit extract showed essentially complete metabolism to mogrol within 8 h at 0.2 mg/mL and 2 mg/mL for siamenoside I, and 8 h at 0.2 mg/mL and 16 h at 2 mg/mL for monk fruit extract, in both male and female pooled fecal homogenates with no apparent sex differences. Overall, no difference was observed in the deglycosylation rates of purified siamenoside I or siamenoside I present in monk fruit extract to the mogrol metabolite further confirming the deglycosylation of mogrosides in the lower gastrointestinal tract.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of Diatomaceous Earth as used in cosmetic formulations. It is reported to function as an abrasive, absorbent, anticaking agent, bulking agent, and opacifying agent in cosmetic products. The Panel reviewed all relevant data, and concluded that Diatomaceous Earth is safe in cosmetics in the present practices of use and concentration described in this safety assessment.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 5 glycolactone ingredients. Glucoheptonolactone and Gluconolactone are reported to function in cosmetics as skin-conditioning agents-miscellaneous, and Gluconolactone is also reported to function as a chelating agent. No functions are reported for the other 3 ingredients. The Panel considered the available data and concluded that Gluconolactone is safe in cosmetics in the present practices of use and concentration described in this safety assessment; however, the Panel concluded the available data are insufficient to make a determination that Galactonolactone, Glucarolactone, Glucoheptonolactone, and Ribonolactone are safe under the intended conditions of use in cosmetic formulations.
The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of Basic Yellow 87, which is reported to function as a hair dye in cosmetic products. The Panel reviewed the available data to determine the safety of this ingredient. The Panel concluded that Basic Yellow 87 is safe for use as a hair dye ingredient in the present practices of use and concentration described in this safety assessment.
Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, was first approved by the US FDA as KETALAR® for induction and maintenance of general anesthesia. Ketamine has been used off-label for depression treatment, while its S-enantiomer, esketamine (SPRAVATO®), is approved for treatment-resistant depression and major depressive disorder with acute suicidal ideation or behavior. High doses of ketamine have been linked to neurotoxicity. The effects of acute ketamine exposure on brain development during childhood and adolescence in humans remain poorly understood. To better characterize the safety of ketamine, we treated juvenile (postnatal day (PND) 21, 30, 35) and adult rats (PND 90) with a single subcutaneous dose of ketamine (50, 75, and 100 mg/kg). Seventy-two hours later, tissue samples were collected. Tissue samples were processed, mounted as 5-µm-thick sections, and stained with H&E for neurohistopathological evaluation. Additionally, key pharmacokinetic parameters of ketamine were determined. Neuronal necrosis was detected in the retrosplenial cortex in adult female rats treated with ketamine (100 mg/kg), while no histological changes were observed in any other groups. These data are the first to demonstrate that acute ketamine can cause neuronal necrosis in adult animals and do not support juvenile rats as having an increased susceptibility to ketamine-induced neuronal death. Adult female rats showed a marked increase in norketamine, the primary metabolite of ketamine in serum. We hypothesize that the elevated levels of norketamine may contribute to these sex- and age-specific histopathological changes.
Advances in the delivery and safety of nucleic acid-based therapeutics are enabling tissue-selective targeting and broadening the reach of genetic medicines. In addition to GalNAc-conjugated oligonucleotides, newer modalities-predominantly antibody- and peptide-conjugated oligonucleotides-combine innovative components with complex and often multimodal mechanisms of action. These constructs may require tailored nonclinical testing strategies to evaluate pharmacology, biodistribution, and component- and construct-driven toxicities. Here, we review the current state of these molecules, collectively termed here as bioconjugated oligonucleotide (BCO) therapeutics, summarize key safety liabilities across the protein scaffold, linker, and oligonucleotide payload, and highlight nonclinical approaches, including predictive safety assessments and in vivo toxicity studies that can support human clinical trials. We also discuss risk-based regulatory considerations that may differ from traditional biologics or small molecules.
Nalmefene is an opioid antagonist used in OPVEE® nasal spray approved for use in patients 12 years of age and older. To support future clinical studies in younger pediatric populations, 2 GLP juvenile rat studies were conducted to assess the safety of nalmefene and its associated systemic exposure. Nalmefene was administered daily via intranasal instillation from postnatal day (PND) 7 to PND 28 (corresponding to birth through approximately 3 years) with recovery to PND 91, or from PND 22 to PND 70 (2 years to adolescent) with recovery to PND 114. Exposures on PND 7 were 28-40 times higher than those on PND 28, and exposures on PND 22 were 3-5 times higher than those on PND 70. Exposures on PND 28 were comparable to those on PND 70, attaining adult levels. Considering the extensive metabolism and urinary clearance of nalmefene, these findings are consistent with the maturation of metabolic and urinary clearance pathways during early development. No effects were observed on clinical signs, ophthalmology, food consumption, femur length, sperm parameters, immune responses, or neurodevelopment as assessed by neurohistopathology and neurobehavioral testing for locomotor activity, sensory function, or learning and memory. There were no macroscopic or microscopic findings indicative of target organ, systemic, or neurotoxicity. The NOAELs were 4.25 mg/dose, the highest doses tested. On PND 28, Cmax (224 ng/mL) and AUC (311 ng·hr/mL) were 21- and 8-fold higher than those reported in human adults, respectively. The AUC-based safety margins in pediatric patients were estimated to range from 1.5 to 12, depending on the age group (birth-12 years; 3-40 kg).
