Human skin permeation of emerging mycotoxins (beauvericin and enniatins)

Abstract

Currently, dermal exposure data of cyclic depsipeptide mycotoxins are completely absent. There is a lack of understanding about the local skin and systemic kinetics and effects, despite their widespread skin contact and intrinsic hazard. Therefore, we provide a quantitative characterisation of their dermal kinetics. The emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) were used as model compounds and their transdermal kinetics were quantitatively evaluated, using intact and damaged human skin in an in vitro Franz diffusion cell set-up and ultra high-performance liquid chromatography (UHPLC)-MS analytics. We demonstrated that all investigated mycotoxins are able to penetrate through the skin. ENN B showed the highest permeation (kp,v=9.44 × 10(-6) cm/h), whereas BEA showed the lowest (kp,v=2.35 × 10(-6) cm/h) and the other ENNs ranging in between. Combining these values with experimentally determined solubility data, Jmax values ranging from 0.02 to 0.35 μg/(cm(2) h) for intact skin and from 0.07 to 1.11 μg/(cm(2) h) for damaged skin were obtained. These were used to determine the daily dermal exposure (DDE) in a worst-case scenario. On the other hand, DDE's for a typical occupational scenario were calculated based on real-life mycotoxin concentrations for the industrial exposure of food-related workers. In the latter case, for contact with intact human skin, DDE's up to 0.0870 ng/(kg BW × day) for ENN A were calculated, whereas for impaired skin barrier this can even rise up to 0.3209 ng/(kg BW × day) for ENN B1. This knowledge is needed for the risk assessment after skin exposure of contaminated food, feed, indoor surfaces and airborne particles with mycotoxins.

Enniatin-containing solutions for oromucosal use: Quality-by-design ex-vivo transmucosal risk assessment of composition variability

“…Overall average lag times ranged from 0.63 to 1.17 h for ENN A1 and ENN B, respectively. These are considerably shorter than the lag times reported for transdermal permeation through intact (AE 8 h) and even damaged (AE 6 h) human skin, when applied in a dose formulation with up to 60% EtOH (Taevernier et al, 2015). This confirms previous observations, explained by the difference in anatomy between skin and mucosa: the skin has an extensive barrier function exerted by the stratum corneum, which the mucosa is lacking.…”

“…Taking into account that the marketed preparations contain up to a 10 times higher enniatin dosage than the dose experimentally applied in this study and assuming linear extrapolation, steady-state plasma concentrations after oromucosal use up to 13.39 mg/L might be expected. Moreover, according to the patient information given for these products (Locabiotal1, patient information leaflet), the spray should be applied every 4 h, likely causing local built-up, which might eventually lead to a mucosal enniatin sink reservoir (Taevernier et al, 2015), from which enniatins can slowly diffuse into the blood circulation and result in undesired chronic exposure to these mycotoxins. It is therefore recommended in the treatment of minor, rather innocent, upper respiratory infections, to question enniatin-based solutions for oromucosal use, since for the mycotoxins present in the formulation, local and systemic toxic effects cannot yet be excluded (Taevernier et al, 2015).…”

“…Moreover, according to the patient information given for these products (Locabiotal1, patient information leaflet), the spray should be applied every 4 h, likely causing local built-up, which might eventually lead to a mucosal enniatin sink reservoir (Taevernier et al, 2015), from which enniatins can slowly diffuse into the blood circulation and result in undesired chronic exposure to these mycotoxins. It is therefore recommended in the treatment of minor, rather innocent, upper respiratory infections, to question enniatin-based solutions for oromucosal use, since for the mycotoxins present in the formulation, local and systemic toxic effects cannot yet be excluded (Taevernier et al, 2015). Table 3 Local mucosa concentrations for enniatins obtained for porcine buccal mucosa applied in 1 mg/mL total enniatins dose solutions with varying EtOH:IPM (V/V) concentrations (mean AE SEM, n = 6).…”

“…However, no data substantiating this claim could be found in literature, questioning its validity. It is likely to assume that enniatins might pass the mucosa, since (i) it was recently demonstrated in an exvivo in-vitro Franz diffusion cell (FDC) experiment that enniatins are in fact capable of crossing the human skin barrier (Taevernier et al, 2015), (ii) it is generally accepted that mucosal permeation is significantly higher than skin permeation (Galey et al, 1976;Squier et al, 1976;Boonen et al, 2010a,b;Hu et al, 2011;Amores et al, 2014), (iii) enniatins in pharmaceutical preparations are mainly formulated in ethanol (EtOH) and isopropyl myristate (IPM), which are both chemical skin and mucosal penetration enhancers (Squier et al, 1986;Kai et al, 1990;Coutel-Egros et al, 1992;Obata et al, 1993;Turunen et al, 1994;Brinkmann and Muller-Goymann, 2003;Williams and Barry, 2004;Nicolazzo et al, 2004;Engelbrecht et al, 2012;Santos et al, 2012) and (iv) a considerable total water solubility of 0.3 mg/mL has been demonstrated for enniatins (Taevernier et al, 2015).…”

“…Therefore, the overall objective of this study was to quantitatively evaluate the transmucosal kinetics of enniatins, using excised porcine buccal mucosa in an ex-vivo in-vitro FDC set-up with the application of a quality-by-design (QbD) risk assessment of the quantitative excipient composition variability. This is of pivotal importance, since enniatins have recently been identified as mycotoxins, which are secondary metabolites produced by fungi, posing a health hazard by exerting a toxic activity on human or animal cells (Jestoi, 2008;Tedjiotsop Feudjio et al, 2010;Faeste et al, 2011;Kolf-Clauw et al, 2013;Devreese et al, 2014;Taevernier et al, 2015). The European Food and Safety Authority (EFSA) recently published their "scientific opinion on the risks to human and animal health related to the presence of beauvericin and enniatins in food and feed".…”