Exposure of Infants to Isoniazid via Breast Milk After Maternal Drug Intake of Recommended Doses Is Clinically Insignificant Irrespective of Metaboliser Status. A Physiologically-Based Pharmacokinetic (PBPK) Modelling Approach to Estimate Drug Exposure of Infants via Breast-Feeding

Isoniazid is a first-line anti-tuberculosis drug recommended for treatment of drug-susceptible Mycobacterium tuberculosis infections. Breast-feeding is not contra-indicated while undergoing isoniazid therapy, even though isoniazid was found to migrate into breast milk, leading to infant drug exposure. Exposure assessment of isoniazid in infants exposed to the drug via breast milk has so far not accounted for the polymorphic expression of the isoniazid metabolising enzyme N-acetyltransferase 2. The aim of this study was to re-visit the safety assessment of maternal isoniazid therapy for infants exposed to the drug via breast milk, while accounting for fast and slow metabolisers in the adult and infant population, as well as for slower metabolism in small infants than in adults. We applied a physiologically-based pharmacokinetic (PBPK) modelling approach to estimate mother and infant external and internal drug exposure non-invasively. Validity of our PBPK models was confirmed through comparison of simulated results with experimental data. Highest recommended oral doses for mothers are daily 300 mg or 900 mg every 3 days. Simulation of maternal intake of 300 mg resulted in oral exposures of 0.58 (95%CI: 0.42–0.69) mg/day and 1.49 (1.22–1.50) mg/day for infants of fast and slow metabolising mothers, respectively. Oral exposures of infants within the first 24 h after maternal intake of 900 mg were 1.75 (1.25–2.06) mg/day and 4.46 (4.00–4.50) mg/day. Maximal drug concentrations in infant plasma ranged between 0.04 and 0.78 mg/L for the two dosing regimens. We therefore conclude that infant exposure to isoniazid via breast milk after maternal drug intake of highest recommended doses is very low. We expect that such low exposure levels most likely do not cause any clinically significant adverse effects in nursed infants

Physiologically Based Toxicokinetic Modelling as a Tool to Support Risk Assessment: Three Case Studies

In this contribution we present three case studies of physiologically based toxicokinetic (PBTK) modelling in regulatory risk assessment. (1) Age-dependent lower enzyme expression in the newborn leads to bisphenol A (BPA) blood levels which are near the levels of the tolerated daily intake (TDI) at the oral exposure as calculated by EFSA. (2) Dermal exposure of BPA by receipts, car park tickets, and so forth, contribute to the exposure towards BPA. However, at the present levels of dermal exposure there is no risk for the adult. (3) Dermal exposure towards coumarin via cosmetic products leads to external exposures of two-fold the TDI. PBTK modeling helped to identify liver peak concentration as the metric for liver toxicity. After dermal exposure of twice the TDI, the liver peak concentration was lower than that present after oral exposure with the TDI dose. In the presented cases, PBTK modeling was useful to reach scientifically sound regulatory decisions

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

The European Registered Toxicologist (ERT) : Current status and prospects for advancement

Acknowledgements We would like to thank the participants of the five workshops in which the issues presented in this paper were discussed and the revised guidelines prepared, as well as the EUROTOX Executive Committee and the societies of toxicology of Sweden, the Netherlands, Switzerland, Austria and France for their support which allowed the workshops to take place.Peer reviewedPostprin

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 mu M amiodarone were 1.00 and 1.99 mu g*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 in use of glucosylated steviol glycosides as a food additive in different food categories

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion on the safety of glucosylated steviol glycosides proposed for use as a new food additive in different food categories. According to the applicant, glucosylated steviol glycosides preparations consist of not less than 95% (on anhydrous basis) total steviol glycosides, made up of glucosylated steviol glycosides of different molecular weights as well as any remaining steviol glycosides. The applicant proposed that glucosylated steviol glycosides and parent steviol glycosides undergo a common metabolic process in pathway following ingestion and suggested that data from steviol glycosides can be used for read‐across to glucosylated steviol glycosides. The limited evidence provided in the application dossier did not demonstrate the complete hydrolysis of the glucosylated steviol glycosides. No toxicological studies on glucosylated steviol glycoside preparations under evaluation have been provided for its assessment. The Panel concluded that the submitted data are insufficient to assess the safety of the glucosylated steviol glycoside preparations to be used as a new food additive

Scientific opinion on the evaluation of authorised ferric sodium EDTA as an ingredient in the context of Regulation (EC) 258/97 on novel foods and Regulation (EU) 609/2013 on food intended for infants and young children, food for special medical purposes and total diet replacement for weight control

The present opinion deals with the evaluation of the proposed increase of the currently authorised maximum amounts of ferric sodium ethylenediaminetetraacetic acid (EDTA) as a novel food ingredient used as a source of iron, and its extension of use in processed cereal‐based foods and baby foods. The applicant also provided information on two forms of ferric sodium EDTA, one previously assessed by EFSA and a new one of finer consistency. To support the proposed changes to the uses of ferric sodium EDTA, the applicant proposed a revision of the current acceptable daily intake (ADI) for EDTA, derived from that set for the food additive calcium disodium EDTA (E 385). The Panel confirmed that ferric sodium EDTA is a source from which iron is bioavailable. In assessing the safety of the proposed revision to the existing specifications for the novel food ingredient ferric sodium EDTA, the Panel noted that this would not discriminate between the previously evaluated substance and the one of finer consistency. In particular, the Panel noted that particle size was not one of the proposed parameters for the revised specifications. The Panel noted that it was not possible to determine whether particles of ferric sodium EDTA in the nano range were present in the product with finer consistency in the solid form. The toxicological data submitted did not add any new relevant information to the database on which the current ADI for EDTA is based. Consequently, the Panel concluded that there was no sound scientific justification to increase the ADI for EDTA and hence increase the use levels of ferric sodium EDTA or introduce additional uses as proposed by the applicant. The Panel recommended that additional toxicological data should be provided to address the shortcomings in the available toxicity database prior to the re‐evaluation of calcium disodium EDTA (E 385)

Evaluation of four new studies on the potential toxicity of titanium dioxide used as a food additive (E 171)

The European Commission requested EFSA to carry out a scientific evaluation on four studies on the potential toxicity of titanium dioxide (TiO2) used as a food additive (E 171) and to indicate whether they would merit re‐opening the existing opinion of EFSA on the safety of TiO2 (E 171) as a food additive. The results of the Bettini et al. (2017) study did not provide enough justification for a new carcinogenicity study, but, should additional useful mechanistic information become available, this could be reconsidered in future. The new in vitro findings in the Proquin et al. (2017) study did not modify the conclusion on the genotoxicity of TiO2 as stated in the previous EFSA opinion of 2016 on the safety of TiO2 (E 171) as a food additive. The effects of engineered TiO2 nanoparticles reported by the Guo et al. (2017) study were of uncertain biological significance and therefore of limited relevance for the risk assessment of the food additive TiO2 (E 171). There was significant uncertainty in the risk assessment performed by Heringa et al. (2016), which did not include a weight of evidence analysis of the whole database. The Panel considered that the four studies evaluated, highlighted some concerns but with uncertainties, therefore their relevance for the risk assessment was considered limited and further research would be needed to decrease the level of uncertainties. Overall, three of the studies, reporting that TiO2 induced various effects in in vitro and in vivo models, may be useful for hazard identification of TiO2. In the fourth study by Heringa et al. (2016), numerous assumptions were made, which resulted in large uncertainty in their conclusion. Altogether, the Panel concluded that the outcome of the four studies did not merit re‐opening the existing opinion of EFSA related to the safety of TiO2 (E 171) as a food additive

Re‐evaluation of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) as food additives

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re‐evaluating the safety of sodium, potassium and calcium salts of fatty acids (E 470a) and magnesium salts of fatty acids (E 470b) when used as food additives. In 1991, the Scientific Committee on Food (SCF) established a group acceptable daily intake (ADI) ‘not specified’ for the fatty acids (myristic‐, stearic‐, palmitic‐ and oleic acid) and their salts. The sodium, potassium, calcium and magnesium salts of fatty acids are expected to dissociate in the gastrointestinal tract to fatty acid carboxylates and their corresponding cations. There were no data on subchronic toxicity, chronic toxicity, reproductive and developmental toxicity of the salts of fatty acids. There was no concern for mutagenicity of calcium caprylate, potassium oleate and magnesium stearate. From a carcinogenicity study with sodium oleate, a no observed adverse effect level (NOAEL) could not be identified but the substance was considered not to present a carcinogenic potential. Palmitic‐ and stearic acid which are the main fatty acids in E 470a and E 470b were already considered of no safety concern in the re‐evaluation of the food additive E 570. The fatty acid moieties of E 470a and E 470b contributed maximally for 5% to the overall intake of saturated fatty acids from all dietary sources. Overall, the Panel concluded that there was no need for a numerical ADI and that the food additives sodium, potassium, calcium and magnesium salts of fatty acids (E 470a and E 470b) were of no safety concern at the reported uses and use levels