Abstract
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.
Highlights
In vitro toxicity assays emerge as an appealing alternative to animal-based toxicity testing aiming to decrease the reliance on animal experimental studies performed in quantitative risk assessment of drugs and chemicals (Adler et al 2011; Punt et al 2018; Strikwold et al 2013)
Human physiologically based pharmacokinetic (PBPK) modeling‐reverse dosimetry based on area under the curve (AUC) and Cmax from the brain cell lysate
The AUCs resulting from the concentrations measured in the in vitro brain cell lysate after daily repeated exposure to 1.25 and 2.5 μM amiodarone on day 14 were 1.00 μg*h/ mL and 1.99 μg*h/mL, respectively, and the doses calculated by in vivo extrapolation (IVIVE) were 3.83 and 7.68 mg/kg, respectively (Table 1, Fig. 2)
Summary
In vitro toxicity assays emerge as an appealing alternative to animal-based toxicity testing aiming to decrease the reliance on animal experimental studies performed in quantitative risk assessment of drugs and chemicals (Adler et al 2011; Punt et al 2018; Strikwold et al 2013) They offer the advantages of reduced cost and time, and are in accordance with the aim to replace and reduce the use of animals in toxicological testing (Lilienblum et al 2008; Punt et al 2018). PBPK models can predict blood or tissue concentrations of a compound or its metabolite(s) over time at any dose, and in combination with concentration-effect data, they allow the analysis of various dosing scenarios This approach enables the translation of in vitro concentration–response relationships into in vivo dose–response curves that are used to define safe exposure levels in an organism (Louisse et al 2017; Zhang et al 2018a)
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