Urinary metabolites of DEET after dermal application on child and adult subjects

Urinary metabolites of DEET of 17 children (5-7 years of age) and 9 adults (23-25 years of age) were examined in the study described in this article. Urine samples were collected from each subject within eight hours after a single dermal application of 10 mL 12% DEET-containing insect repellent. Two metabolites, m-diethylaminocarbonyl benzoic acid (R3N0) and N-ethyl-m-toluamide (RON1), with unchanged DEET, were identified in the urine. The major metabolite was R3NO, which was 78.2% and 46.1% of the total DEET metabolites from children and adults, respectively, indicating that the pathway of ring methyl oxidation predominated. The recovered DEET metabolites were observed significantly more from children (1,116 pg) than from adults (446.2 pg) (p < .001). The difference in dermal absorption, albeit primarily attributed to DEET loading, was found to be related to height by regression analysis. The inverse association between height and dermal absorption of DEET suggests that shorter individuals (i.e., children) are subjected to dermal uptake of DEET. To avoid unnecessary exposure, parents need to be cautious when applying DEET-containing insect repellent on children.