Prediction of the dose range for adverse neurological effects of amiodarone in patients from an in vitro toxicity test by in vitro-in vivo extrapolation.

Amiodarone is an antiarrhythmic agent inducing adverse effects on the nervous system, among others. We applied physiologically based pharmacokinetic (PBPK) modeling combined with benchmark dose modeling to predict, based on published in vitro data, the in vivo dose of amiodarone which may lead to adverse neurological effects in patients. We performed in vitro-in vivo extrapolation (IVIVE) from concentrations measured in the cell lysate of a rat brain 3D cell model using a validated human PBPK model. Among the observed in vitro effects, inhibition of choline acetyl transferase (ChAT) was selected as a marker for neurotoxicity. By reverse dosimetry, we transformed the in vitro concentration-effect relationship into in vivo effective human doses, using the calculated in vitro area under the curve (AUC) of amiodarone as the pharmacokinetic metric. The upper benchmark dose (BMDU) was calculated and compared with clinical doses eliciting neurological adverse effects in patients. The AUCs in the in vitro brain cell culture after 14-day repeated dosing of nominal concentration equal to 1.25 and 2.5 µM amiodarone were 1.00 and 1.99 µg*h/mL, respectively. The BMDU was 385.4 mg for intravenous converted to 593 mg for oral application using the bioavailability factor of 0.65 as reported in the literature. The predicted dose compares well with neurotoxic doses in patients supporting the hypothesis that impaired ChAT activity may be related to the molecular/cellular mechanisms of amiodarone neurotoxicity. Our study shows that predicting effects from in vitro data together with IVIVE can be used at the initial stage for the evaluation of potential adverse drug reactions and safety assessment in humans.

Safety assessment of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance 'phosphorous acid, triphenyl ester, polymer with 1,4-cyclohexanedimethanol and polypropylene glycol, C10-16 alkyl esters', when used as an additive in all types of polyolefins. The substance is a polymer containing ≤ 13% w/w of a low molecular weight fraction (LMWF, < 1000 Da). A polyethylene sample with 0.15% w/w of the substance was used in a comprehensive set of migration tests with food simulants. The specific migration was up to 0.014 and 0.023 mg/kg in 4% acetic acid and 10% ethanol, respectively. Migration into olive oil was estimated by the Panel to be up to 5.3 mg/kg under worst-case conditions of use. The migrating LMWF species were comprehensively identified. Those without phosphorous were either without alerts for genotoxicity or listed in Regulation (EU) 10/2011 with worst-case migrations well below their respective specific migration limits. Toxicological studies were performed using phosphite and phosphate versions of the substance enriched in its LMWF. The substance does not raise a concern for genotoxicity. From a repeated dose 90-day oral toxicity study in rats with a 50:50 phosphite:phosphate blend, the Panel identified a NOAEL of 250 mg/kg bw per day for each component of the blend. No delayed neurotoxicity in hens was observed. The CEP Panel concluded that the substance does not raise a safety concern for the consumer if its LMWF is not higher than 13% w/w, if it is used at up to 0.15% w/w in polyolefin materials and articles intended for contact with all food types, except for infant formula and human milk, for long-term storage at room temperature and below, after hot-fill and/or heating up to 100°C for up to 2 h, and if its migration does not exceed 5 mg/kg food.

Safety assessment of mixtures of 1,9-nonanediamine (NMDA) and 2-methyl-1,8-octanediamine (MODA), for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of mixtures of 1,9-nonanediamine (NMDA) and 2-methyl-1,8-octanediamine (MODA) when used to produce polyamide food contact materials for contact with all food types for long-term storage at room temperature and below, including heating up to 121°C for up to 2 h. The polyamide material is also intended to be used for repeated use up to 121°C with short contact (up to 30 min). The polymer typically contains ■■■■■ of a low molecular weight fraction (LMWF, < 1000 Da). The specific migration was measured with polyamide samples in a set of migration tests with 3% acetic acid and 10% ethanol. NMDA and MODA were not detected at ■■■■■, respectively. The specific migration of the LMWF consisting of NMDA/MODA-related species was up to ■■■■■. The overall migration in olive oil was below the detection limit (3 mg/dm2). The most abundant migrating LMWF oligomers were identified. Toxicological studies were performed with NMDA, MODA and with polyamide formulations enriched in the LMWF. The results of genotoxicity assays did not raise a concern. From a repeated-dose oral 90-day toxicity study in rats, the Panel identified a no observed adverse effect level (NOAEL) of 1000 mg/kg body weight per day for the migrating LMWF. The CEP Panel concluded that NMDA/MODA mixtures do not raise a safety concern for the consumer when used as comonomer with terephthalic acid to manufacture polyamide articles intended for contact with all food types, except for infant formula and human milk, if the migration of NMDA and MODA does not exceed 0.05 mg/kg food (as a sum of the two substances) and if the migration of the LMWF consisting of NMDA/MODA-related species does not exceed 5 mg/kg food.

Safety assessment of the substance calcium tert-butylphosphonate for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids assessed the safety of calcium tert-butylphosphonate, which is intended to be used as a nucleating agent up to 0.15% w/w for the manufacture of polyolefin food contact materials (FCM) and articles for single and repeated use, in contact with all types of food, including infant formula and human milk. Specific migration was tested using polyethylene samples in 10% ethanol, 3% acetic acid and 95% ethanol for 2 h at 100°C, followed by 238 h at 40°C. Results for all three simulants were near or below the limit of detection of 10 µg/kg. As the solubility of the substance is far above the reported migration and above 60 mg/kg food, no assessment of the particle fraction was needed, and the conventional risk assessment was followed. The substance did not induce gene mutations in bacterial cells and structural chromosomal aberrations in mammalian cells, thus, did not raise concern for genotoxicity. The Panel considered that the use of the substance did not give rise to safety concern related to neurotoxicity for the general population, but this conclusion could not be applied to infants below 16 weeks of age, due to their specific sensitivity and the absence of dedicated data. The Panel concluded that calcium tert-butylphosphonate does not raise a safety concern for the consumer if it is used as a nucleating agent up to 0.15% w/w in the manufacture of polyolefin FCM that are intended to be in contact with all types of food for storage above 6 months at room temperature and below, including temperatures up to 100°C for maximum 2 h and up to 130°C for short durations. The Panel could not evaluate the safety of use to manufacture FCM for contact with infant formula and human milk.

Safety assessment of the substance amines, di-C14-C20-alkyl, oxidised, from hydrogenated vegetable oil, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of amines, di-C14-C18-alkyl, oxidised, renamed by the Panel as amines, di-C14-C20-alkyl, oxidised, from hydrogenated vegetable oil. The substance amines, bis(hydrogenated tallow alkyl) oxidised, consisting of the same components, but originating from tallow, is currently authorised as FCM substance No 768. The vegetable-sourced substance is intended to be used at up to 0.1% w/w as antioxidant and/or stabiliser in the manufacture of polyolefin food contact materials (FCM) and articles intended for contact with dry, aqueous and acidic foods. The substance is a mixture consisting of linear N,N-dialkyl hydroxylamines and their corresponding amine, nitrone and oxime derivatives, as well as further components: tert-N-oxides, secondary amides and carboxylic acids. Specific migration was tested from polyethylene samples in 10% ethanol and 3% acetic acid for 2 h at 100°C followed by 10 days at 60°C. None of the non-authorised components were detected to migrate at detection limits (LoD) in the range 0.003-0.029 mg/kg. The LoD of authorised carboxylic acids was 0.35 mg/kg. The Panel reassessed the genotoxicity studies carried out on FCM No 768 and evaluated two new bacterial reverse mutation tests on the nitrone and oxime derivatives as well as new (qualitative/quantitative) structure-activity relationship (Q)SAR analyses on other components. The Panel concluded that the substance did not raise a concern for genotoxicity. The Panel concluded that the substance is not of safety concern for the consumers if it is used as an additive at 0.1% w/w in the manufacture of polyolefin FCM intended to be in contact with foods simulated by food simulants A, B, C and E, except for infant formula and human milk, for storage above 6 months at room temperature and below, including hot-fill conditions and heating up to 100°C for 2 h.

Prediction of in vivo prenatal chlorpyrifos exposure leading to developmental neurotoxicity in humans based on in vitro toxicity data by quantitative in vitro-in vivo extrapolation.

Introduction: Epidemiological studies in children suggested that in utero exposure to chlorpyrifos (CPF), an organophosphate insecticide, may cause developmental neurotoxicity (DNT). We applied quantitative in vitro-in vivo extrapolation (QIVIVE) based on in vitro concentration and non-choline esterase-dependent effects data combined with Benchmark dose (BMD) modelling to predict oral maternal CPF exposure during pregnancy leading to fetal brain effect concentration. By comparing the results with data from epidemiological studies, we evaluated the contribution of the in vitro endpoints to the mode of action (MoA) for CPF-induced DNT. Methods: A maternal-fetal PBK model built in PK-Sim® was used to perform QIVIVE predicting CPF concentrations in a pregnant women population at 15 weeks of gestation from cell lysate concentrations obtained in human induced pluripotent stem cell-derived neural stem cells undergoing differentiation towards neurons and glia exposed to CPF for 14 days. The in vitro concentration and effect data were used to perform BMD modelling. Results: The upper BMD was converted into maternal doses which ranged from 3.21 to 271 mg/kg bw/day. Maternal CPF blood levels from epidemiological studies reporting DNT findings in their children were used to estimate oral CPF exposure during pregnancy using the PBK model. It ranged from 0.11 to 140 µg/kg bw/day. Discussion: The effective daily intake doses predicted from the in vitro model were several orders of magnitude higher than exposures estimated from epidemiological studies to induce developmental non-cholinergic neurotoxic responses, which were captured by the analyzed in vitro test battery. These were also higher than the in vivo LOEC for cholinergic effects. Therefore, the quantitative predictive value of the investigated non-choline esterase-dependent effects, although possibly relevant for other chemicals, may not adequately represent potential key events in the MoA for CPF-associated DNT.

Safety assessment of 'waxes, paraffinic, refined, derived from petroleum-based or synthetic hydrocarbon feedstock, low viscosity' for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) assessed the safety of the 'waxes, paraffinic, refined, derived from petroleum-based or synthetic hydrocarbon feedstock, low viscosity' (FCM No. 93), for which the uses were requested to be extended for articles in contact with fatty foods. Migration from low-density polyethylene samples containing 1% w/w of a representative wax was tested in food simulants. In fatty food simulants, the migration of mineral oil saturated hydrocarbons (MOSH) ≤ C35 was 142 mg/kg food, exceeding the overall migration limit for plastic FCM. Mineral oil aromatic hydrocarbons (MOAH) with at least two rings are largely removed during the manufacturing process. Based on various lines of evidence, the Panel concluded that any concern for the potential presence of MOAH with two or more conjugated aromatic rings can be ruled out. Based on the genotoxicity studies and on the content of polycyclic aromatic hydrocarbons (PAHs), the substance does not raise a concern for genotoxicity. Available toxicokinetic data showed a limited accumulation of MOSH. No adverse effects were observed up to the highest tested dose of 9 g/kg body weight per day in a 90-day repeated oral toxicity study in Sprague-Dawley rats. The available results showed that FCM No. 93 is devoid of endocrine activity. The provided information on chronic toxicity and carcinogenicity was limited and inadequate to reach conclusions on these endpoints. Therefore, the CEP Panel concluded that under the intended and tested conditions of uses, the substance does not raise safety concern for the consumer if used to a level ensuring that its migration into food is no more than 5 mg/kg.

Safety assessment of the substance poly(2-hydroxypropanoic acid), n-octyl/n-decyl esters, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of poly(2-hydroxypropanoic acid), n-octyl/n-decyl esters (OLA8), which is intended to be used as a plasticiser into polylactic acid (PLA) in contact with non-fatty foods. OLA8 is intended to be used at up to 5% and 15% w/w with or without starch, respectively (or with other additives with similar function). The migration for 10 days at 40°C from the film without starch was 0.16 mg/kg in 10% ethanol and 0.01 mg/kg in 3% acetic acid, while from the film with the starch it was well above 0.05 mg/kg food in all simulants. Some of the testing conditions were inconsistently reported. The substance did not induce gene mutations in bacterial cells and did not induce structural chromosomal aberrations or polyploidy in mammalian cells, thus, does not raise concern for genotoxicity. Instead of providing a 90-day oral toxicity study, a hydrolysis study in ■■■■■ was submitted to read-across from the authorised starting substances, ■■■■■ and the ■■■■■. However, the data provided did not allow to perform the read-across, thus no appropriate toxicological data were provided to support migration above 0.05 mg/kg food (including for contact with 10% ethanol and use in combination with starch). The Panel concluded that OLA8 does not raise a safety concern for the consumer if it is used as an additive at up to 15% w/w in the manufacture of PLA articles that do not contain starch (and other additives with similar function), that are intended to be in contact for 10 days at 40°C with foods simulated by 3% acetic acid and from which the migration does not exceed 0.05 mg/kg food.

In Vitro-In Vivo Extrapolation by Physiologically Based Kinetic Modeling: Experience With Three Case Studies and Lessons Learned.

Physiologically based kinetic (PBK) modeling has been increasingly used since the beginning of the 21st century to support dose selection to be used in preclinical and clinical safety studies in the pharmaceutical sector. For chemical safety assessment, the use of PBK has also found interest, however, to a smaller extent, although an internationally agreed document was published already in 2010 (IPCS/WHO), but at that time, PBK modeling was based mostly on in vivo data as the example in the IPCS/WHO document indicates. Recently, the OECD has published a guidance document which set standards on how to characterize, validate, and report PBK models for regulatory purposes. In the past few years, we gained experience on using in vitro data for performing quantitative in vitro-in vivo extrapolation (QIVIVE), in which biokinetic data play a crucial role to obtain a realistic estimation of human exposure. In addition, pharmaco-/toxicodynamic aspects have been introduced into the approach. Here, three examples with different drugs/chemicals are described, in which different approaches have been applied. The lessons we learned from the exercise are as follows: 1) in vitro conditions should be considered and compared to the in vivo situation, particularly for protein binding; 2) in vitro inhibition of metabolizing enzymes by the formed metabolites should be taken into consideration; and 3) it is important to extrapolate from the in vitro measured intracellular concentration and not from the nominal concentration to the tissue/organ concentration to come up with an appropriate QIVIVE for the relevant adverse effects.

Safety assessment of the active substances cyclooctene homopolymer and cobalt stearate in combination for use in active food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the combined use of cyclooctene homopolymer (PCOE) and cobalt stearate (CoS) intended as a oxygen scavenger in the packaging of all kinds of food stored at room temperature or below for up to 6 months. The CoS is the oxidation catalyst and the PCOE is intentionally oxidised for the oxygen scavenging function. They are incorporated into a plastic layer that is intended to be either in direct or indirect contact with the food. The potential migration of cobalt and cyclooctene monomer were below their respective specific migration limit (SML). The potential migration of PCOE non-oxidised oligomeric low molecular weight fraction (LMWF) < 1,000 Da was estimated to be up to ■■■■■ The Panel concluded that this fraction does not raise concern for genotoxicity potential and that the no observed adverse effect level (NOAEL) derived from a subchronic toxicity study would ensure a margin of exposure large enough to not raise a safety concern. However, the Panel considered the analysis of the oxidised PCOE LMWF not sufficiently comprehensive, i.e. that additional oxidation products of different nature may be formed, and that the limit of detection corresponding to ca. ■■■■■ for individual substances is too high. The oxidised PCOE LMWF was not covered by the genotoxicity tests or the 90-day study on the PCOE oligomers. The assessment of the identified potential oxidised migrants was considered conclusive, but not that of the migrants having remained undetected. Therefore, the CEP Panel was not able to conclude on the safety of the proposed use of cyclooctene homopolymer and cobalt stearate together as active substances in a layer for scavenging oxygen, either in direct contact with the food or separated from the food by a passive layer of polymer.

Safety assessment of the substance nano precipitated calcium carbonate for use in plastic food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance 'nano precipitated calcium carbonate', FCM substance No. 1087, the particles size of which is in the range of ■■■■■, with a median of ■■■■■. The substance is intended to be used as a filler in all plastics at up to 5% w/w for contact with acidic food and at up to 40% w/w for contact with all other types of food. Articles made with the substance are intended for long-term storage at room temperature or below. The particulate form of the calcium carbonate dissolved rapidly under simulated gastric conditions and, therefore, in accordance with the EFSA Guidance on Particle - Technical Requirements (2021), an assessment of the particles in nanoform is not required and a conventional risk assessment is sufficient. Calcium carbonate, not in nanoform, is authorised for use in plastic FCM without specific migration limit (FCM No. 21) and for use as a food additive (E 170). Migration, from low-density polyethylene (LDPE) containing 40% of the substance, was below 0.03 mg/kg in isooctane and 95% ethanol, and 5.4 mg/kg in 10% ethanol. For LDPE containing 5% of the substance, corresponding to the maximum intended amount for contact with acidic foods, the migration was 17 mg/kg. Therefore, the CEP Panel concluded that the substance nano precipitated calcium carbonate is not of safety concern for consumers when used as a filler in all types of polymer for all types of food, except for infant food formulae. The Panel noted, however, that for acidic foods, the overall migration limit may be exceeded.

Safety assessment of the substance chopped carbon fibres, from carbonised polyacrylonitrile, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of chopped carbon fibres, from carbonised polyacrylonitrile, as food contact material (FCM) substance No 1086, which is intended to be used as a filler for polyether ether ketone (PEEK) polymer at up to 40% w/w. The plastic is intended for repeated use in contact with all types of foods under all conditions of use. The chopped carbon fibres have a length of ■■■■■ and a diameter of ■■■■■, with no fragments lower than ■■■■■ in any dimension. They do not include a fraction of particles at the nanoscale and are fully embedded in the PEEK matrix, and therefore the fibres and any fragments are not expected to migrate. Based on the results of a battery of three genotoxicity tests, the Panel concluded that the substance does not raise a concern for genotoxicity. Therefore, the CEP Panel concluded that the substance chopped carbon fibres, from carbonised polyacrylonitrile, with a minimum carbon content of 95% (at sizes not at the nanoscale) does not raise a safety concern for the consumer if the substance is used as a filler at up to 40% w/w for PEEK plastic in contact with all food types and under all conditions of use.

Safety assessment of the substance fatty acid-coated nano precipitated calcium carbonate for use in plastic food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance identified by the applicant as 'fatty acid-coated nano precipitated calcium carbonate'. It is intended to be used as a filler in all plastics at up to 5% for contact with acidic food and at up to 40% for contact with all other types of food. Articles made with the substance are intended for long-term storage over 6 months at room temperature and below. No information was provided on the mechanism of coating as to whether there is chemical modification of the surface and/or physical adsorption. The substance was not properly characterised, either as pristine material or when incorporated into plastic. Contrary to the non-coated material, data show that the coated material does not dissolve fully and quickly under pH conditions simulating gastrointestinal tract. Surface analysis with electron microscopy of low-density polyethylene (LDPE) samples before and after migration experiments showed major differences that indicate release of the substance from the surface after the tests with 3% acetic acid and to a lesser extent with 10% ethanol. This is consistent with measurable migrations that were up to 39 mg CaCO3/kg when using an LDPE sample made with 5% of the substance in contact with acetic acid for 64 days at 40°C. The required data on the release of nanoparticles and on the potential toxicity of the substance in nanoform were not provided. Therefore, the Panel could not conclude on the safe use of the substance.

Safety assessment of diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl] phosphonate for use in a food contact material.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl] phosphonate, FCM substance No. 1007, which is intended to be used in the polymerisation reaction to make poly(ethylene 2,5-furandicarboxylate) (PEF) plastic. The substance is intended to become a component of the backbone of the polymer and has an antioxidant function that provides thermal stability to the polyester during heat processing. The resulting plastic is intended to be used in contact with all types of food under any condition of time and temperature. A PEF sample made using 0.1% w/w of the substance (which is the maximum intended use) was used in a comprehensive set of migration tests with food simulants. The migration of the substance was below the quantification limits estimated around 10 µg/kg. Solvent extraction tests showed no presence of impurities or breakdown products of the substance. The toxicological data provided are the same as those submitted by the same applicant and previously evaluated. The resulting assessment and conclusions are considered still valid by the CEP Panel. Therefore, the CEP Panel concluded that the substance diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate does not raise a safety concern for the consumer if used at up to 0.1% w/w (based on the weight of the polymer) in the polymerisation to make PEF intended for contact with all types of foods under any contact conditions.

Safety assessment of bleached cellulose pulp for use in plastic food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids assessed the safety of the substance bleached cellulose pulp, consisting of cellulose fibres (70-92%) and hemicellulose (8-30%) obtained from pine and spruce wood. The substance is intended to be used ■■■■■ in polyethylene and polypropylene food contact materials. The final articles are intended to be used for all food types and for long-term storage at room temperature, with or without a short time at higher temperature, including hot-fill. Low-density polyethylene samples containing ■■■■■ of the substance were subjected to a broad set of migration tests with food simulants and extraction tests with dichloromethane. The limits of detection ranged from ■■■■■ (when specified). The Panel noted that they do not ensure the detection of genotoxic substances at a concentration leading to a human exposure above the Threshold of Toxicological Concern. Moreover, not all possibly migrating substances were identified or amenable to the analytical methods applied. No toxicological data were provided for the substance itself, as its migration into food is not expected. The safety of the potentially migrating substances of low molecular mass detected was addressed individually and was considered adequate. However, the Panel considered this approach insufficient owing to a substantial fraction of unidentified components. The Panel concluded that the information provided by the applicant does not allow the safety assessment of the substances below 1,000 Da from bleached cellulose pulp from pine and spruce wood used in plastic food contact materials potentially migrating into food. Therefore, the Panel could not conclude on the safety of the use of bleached cellulose pulp from pine and spruce wood as a plastic additive.

OpenCYP: An open source database exploring human variability in activities and frequencies of polymophisms for major cytochrome P-450 isoforms across world populations.

The open source database "OpenCYP database" has been developed based on the results of extensive literature searches from the peer-reviewed literature. OpenCYP provides data on human variability on baseline of activities and polymophism frequencies for selected cytochrome P-450 isoforms (CYP1A2, CYP2A6, CYP2D6, CYP3A4/3A5 and CYP3A7) in healthy adult populations from world populations. CYP enzymatic activities were generally expressed as the metabolic ratio (MR) between an unchanged probe drug and its metabolite(s) in urine or plasma measured in healthy adults. Data on other age groups were very limited and fragmented, constituting an important data gap. Quantitative comparisons were often hampered by the different experimental conditions used. However, variability was quite limited for CYP1A2, using caffeine as a probe substrate, with a symmetrical distribution of metabolic activity values. For CYP3A4, human variability was dependent on the probe substrate itself with low variability when data considering the dextromethorphan/demethilathed metabolite MR were used and large variability when the urinary 6ß-hydroxycortisol/cortisol ratio was used. The largest variability in CYP activity was shown for CYP2D6 activity, after oral dosing of dextromethorphan, for which genetic polymorphisms are well characterised and constitute a significant source of variability. It is foreseen that the OpenCYP database can contribute to promising tools to support the further development of QIVIVE and PBK models for human risk assessment of chemicals particularly when combined with information on isoform-specific content in cells using proteomic approaches.

Human variability in glutathione-S-transferase activities, tissue distribution and major polymorphic variants: Meta-analysis and implication for chemical risk assessment.

The input into the QIVIVE and Physiologically-Based kinetic and dynamic models of drug metabolising enzymes performance and their inter-individual differences significantly improve the modelling performance, supporting the development and integration of alternative approaches to animal testing. Bayesian meta-analyses allow generating and integrating statistical distributions with human in vitro metabolism data for quantitative in vitro-in vivo extrapolation. Such data are lacking on glutathione-S-transferases (GSTs). This paper reports for the first time results on the human variability of GST activities in healthy individuals, their tissue localisation and the frequencies of their major polymorphic variants by means of extensive literature search, data collection, data base creation and meta-analysis. A limited number of papers focussed on in vivo GST inter-individual differences in humans. Ex-vivo total GST activity without discriminating amongst isozymes is generally reported, resulting in a high inter-individual variability. The highest levels of cytosolic GSTs in humans are measured in the kidney, liver, adrenal glands and blood. The frequencies of GST polymorphisms for cytosolic isozymes in populations of different geographical ancestry were also presented. Bayesian meta-analyses to derive GST-related uncertainty factors provided uncertain estimates, due to the limited database. Considering the relevance of GST activities and their pivotal role in cellular adaptive response mechanisms to chemical stressors, further studies are needed to identify GST probe substrates for specific isozymes and quantify inter-individual differences.

Safety assessment of the substance phosphorous acid, triphenyl ester, polymer with alpha-hydro-omega-hydroxypoly[oxy(methyl-1,2-ethanediyl)], C10-16 alkyl esters (FCM No 1076), for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) assessed the safety of the substance 'phosphorous acid, triphenyl ester, polymer with alpha-hydro-omega-hydroxypoly[oxy(methyl-1,2-ethanediyl)], C10-16 alkyl esters' obtained by reaction of ■■■■■ This food contact material (FCM) substance No 1076 was evaluated by the CEP Panel in 2019 for its use in high impact polystyrene. This opinion deals with the safety assessment of the substance when used as an additive at up to 0.025% w/w in acrylonitrile-butadiene-styrene (ABS) copolymers. The plastic is intended for repeated use in contact with aqueous, acidic, alcoholic and oil-in-water emulsion foods, for long-term storage at room temperature and below. Migration from ABS formulated with the substance at 0.02% w/w was up to 0.002 mg/kg in 10% ethanol, 0.005 mg/kg in 3% acetic acid and 0.027 mg/kg in 50% ethanol. Migration levels into 50% ethanol declined under repeated-use test conditions and this decline was considered to also cover repeated contacts with 10% ethanol and 3% acetic acid simulants. The toxicological data are the same as those submitted by the same applicant in a previous dossier (EFSA-Q-2018-00411). They were reported in the scientific opinion of the CEP Panel in 2019 and the conclusions on toxicity are still valid. Overall, the CEP Panel concluded that the substance phosphorous acid, triphenyl esters, polymer with alpha-hydro-omega-hydroxypoly[oxy(methyl-1,2-ethanediyl)], C10-16 alkyl esters, does not raise a safety concern for the consumer if it is used as an additive at up to 0.025% w/w in ABS materials and articles for single and repeated use in contact with aqueous, acidic, alcoholic and oil-in-water emulsion foods, for long-term storage at room temperature and below, and if its migration does not exceed 0.05 mg/kg food.

Safety assessment of the substance silver nanoparticles for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the additive silver nanoparticles intended to be used in plastics. All the silver particles are in the size range of 1-100 nm, with about 15 nm mean diameter and 99% by number of particles below 20 nm. The additive is intended to be used as a surface biocide at up to 0.025% w/w in non-polar plastics for contact with a wide variety of foods, times, temperatures and food contact surface/mass of food ratios. The particulate form is maintained when the additive is incorporated into plastics, albeit with some aggregation/agglomeration observed. The data and information on theoretical considerations, on specific migration and abrasion tests show that, under the intended and tested conditions of uses, the silver nanoparticles stay embedded in the polymer, do not migrate and resist release by abrasion, thus, do not give rise to exposure via food and to toxicological concern. There is migration of silver in soluble ionic form up to 6 µg/kg food from the surface of the additive particles. This is below the group restriction of 50 µg silver/kg food proposed by the AFC Panel in 2004 and would lead to a maximum exposure from FCM that would be below the acceptable daily intake (ADI) of 0.9 µg silver ions/kg body weight (bw) per day established by ECHA. Therefore, the Panel concluded that the substance does not raise safety concern for the consumer if used as an additive at up to 0.025% w/w in polymers, such as polyolefins, polyesters and styrenics, that do not swell in contact with aqueous foods and food simulants. The Panel noted, however, that exposure to silver from other sources of dietary exposure may exceed the ADI set by ECHA.

Integrating biokinetics and in vitro studies to evaluate developmental neurotoxicity induced by chlorpyrifos in human iPSC-derived neural stem cells undergoing differentiation towards neuronal and glial cells.

For some complex toxicological endpoints, chemical safety assessment has conventionally relied on animal testing. Apart from the ethical issues, also scientific considerations have been raised concerning the traditional approach, highlighting the importance for considering real life exposure scenario. Implementation of flexible testing strategies, integrating multiple sources of information, including in vitro reliable test methods and in vitro biokinetics, would enhance the relevance of the obtained results. Such an approach could be pivotal in the evaluation of developmental neurotoxicity (DNT), especially when applied to human cell-based models, mimicking key neurodevelopmental processes, relevant to human brain development. Here, we integrated the kinetic behaviour with the toxicodynamic alterations of chlorpyrifos (CPF), such as in vitro endpoints specific for DNT evaluation, after repeated exposure during differentiation of human neural stem cells into a mixed culture of neurons and astrocytes. The upregulation of some cytochrome P450 and glutathione S-transferase genes during neuronal differentiation and the formation of the two major CPF metabolites (due to bioactivation and detoxification) supported the metabolic competence of the used in vitro model. The alterations in the number of synapses, neurite outgrowth, brain derived neurotrophic factor, the proportion of neurons and astrocytes, as well as spontaneous electrical activity correlated well with the CPF ability to enter the cells and be bioactivated to CPF-oxon. Overall, our results confirm that combining in vitro biokinetics and assays to evaluate effects on neurodevelopmental endpoints in human cells should be regarded as a key strategy for a quantitative characterization of DNT effects.