Comparative insights into the dermal absorption, distribution, and elimination of conventional and nano formulations of tebuconazole in rats.

BACKGROUND

Nanopesticides have been developed to improve the efficacy and utilization efficiency of conventional formulations; however, information on their toxicokinetics behavior following dermal exposure remains limited. Tebuconazole is a widely used triazole fungicide for which dermal exposure represents an important occupational route. This study aimed to compare the absorption, distribution, and elimination of tebuconazole in rats after dermal exposure to nano-formulations (nanoemulsion and nano-capsules) and conventional formulations (suspension concentrate and micro-capsules), providing data relevant for human health risk assessment.

RESULTS

Permeable fraction of suspension concentrate, nanoemulsion, nano-capsules, and micro-capsules were 6.5%, 7.7%, 7.4% and 3.7%, respectively, showing a significant negative correlation with particle size of formulated products (r = -0.98, P < 0.05). Because of the lipophilicity, concentrations of tebuconazole in fat (49.2-302.4 μg kg-1) were highest, followed by the ovary (27.8-168.7 μg kg-1) and liver (30.8-140.1 μg kg-1), and those in lung (6.4-45 μg kg-1) were lowest. The maximum tissue concentrations following exposure to micro-capsules were significantly lower than those observed for nano-formulations and suspension concentrate. Tebuconazole was largely eliminated from rat tissues within 78 h after exposure and followed first-order kinetics (R2 ≥ 0.73). The elimination half-lives of nano-formulations (nanoemulsion: 0.7-8.5 h; nano-capsules: 0.8-9.2 h) were generally shorter than those of conventional formulations (suspension concentrate: 4.1-19.3 h; micro-capsules: 1.0-115.5 h). Feces (10.3-345.3 μg kg-1) was the primary excretion route compared with urine (3.5-5.1 μg kg-1).

CONCLUSION

This study demonstrates that formulation type and particle size influence the dermal absorption and toxicokinetics behavior of tebuconazole in rats. The results provide quantitative toxicokinetics data that improve the understanding of dermal exposure to nano-formulated fungicides. © 2026 Society of Chemical Industry.