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In vitro dermal absorption of metiram using human skin preparations
Eric Fabian1, Claudia Rosenbaum2, Bernd Kratzer2
1BASF SE, Carl-Bosch-Str. 38, 67056 Ludwigshafen, Germany.
Abstract:
Metiram is a polymeric plant protection fungicidal product. Since farm workers can potentially be exposed to the used solo-formulation, polyram, its dermal penetration is important for the assessment of its safety. Previous dermal penetration studies indicated a low penetration of metiram (≤ 1% of the applied dose), when applied in polyram or in the almost identical technical concentrate, metiram TK. Here, we present an in vitro human skin absorption study conducted according to OECD guideline 428. In this study, synthesized polymeric 14C-radiolabelled metiram in polymeric "unlabeled" solo-formulation, polyram, was used. Single doses of radioactive metiram were applied to human skin preparations in vitro (4 donors per dose group, 2 replicates each) for 8 h, under semi-occluded conditions in Franz-like diffusion cells, using a flow-through diffusion system. Under these test conditions, dermal absorption of the low dose, which represents spray dilution concentrations, was 0.34 ± 0.48% of applied dose; and dermal absorption of the high dose (formulation concentrate) was negligible (<0.0015 % of the applied dose). These results confirm the low dermal absorption of polymeric metiram and indicate that slight differences in applied formulations have minimal impact on its penetration properties.
Insights
Dermal absorption of metiram, a polymeric fungicide, is very low in humans. Even at high concentrations, penetration through the skin was negligible, confirming its safety for farmworkers.
Area of Science:
- Environmental toxicology
- Dermal absorption studies
- Agricultural chemical safety
Background:
- Metiram is a polymeric fungicide used in agriculture.
- Farmworker exposure to metiram (polyram) necessitates understanding its dermal penetration for safety assessment.
- Previous studies indicated low metiram penetration (≤1%).
Purpose of the Study:
- To quantify the in vitro dermal absorption of polymeric metiram in human skin.
- To assess metiram's penetration properties using OECD guideline 428.
- To evaluate the impact of formulation concentration on dermal absorption.
Main Methods:
- In vitro human skin absorption study using OECD guideline 428.
- Application of 14C-radiolabelled metiram in polyram formulation to human skin preparations.
- Use of Franz-like diffusion cells with a flow-through system for 8-hour exposure.
- Testing of both low-dose (spray dilution) and high-dose (concentrate) applications.
Main Results:
- Low-dose dermal absorption was 0.34 ± 0.48% of the applied dose.
- High-dose dermal absorption was negligible (<0.0015% of the applied dose).
- Polymeric metiram demonstrated minimal skin penetration under tested conditions.
Conclusions:
- Confirms the low dermal absorption of polymeric metiram.
- Suggests minimal impact of formulation concentration on metiram's penetration properties.
- Supports the safety assessment of metiram for agricultural use regarding dermal exposure.
