Assessment of dermal absorption of DEET-containing insect repellent and oxybenzone-containing sunscreen using human urinary metabolites

• Published in: Environmental science and pollution research international 2015-05, Vol.22 (9), p.7062-7070
• Main Authors: Yiin, Lih-Ming, Tian, Jia-Ni, Hung, Chien-Che
• Format: Article
• Language: English
• Subjects: Absorption; active ingredients; Adult; application methods; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Benzophenones - pharmacokinetics; Benzophenones - urine; Biomarkers; deet; DEET - pharmacokinetics; DEET - urine; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental protection; Environmental science; Female; Humans; insect repellents; Insect Repellents - pharmacokinetics; Insect Repellents - urine; Insecticides; Insects; Male; Metabolism; Metabolites; Oxidation; Research Article; Skin; Skin - metabolism; Skin Absorption; Studies; Sunscreen; Sunscreening Agents - pharmacokinetics; Urine; Waste Water Technology; Water Management; Water Pollution Control; Young Adult
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-014-3915-3

Mutual enhancement of dermal absorption of N,N-diethyl-m-toluamide (DEET) and oxybenzone (OBZ) has been reported recently with DEET and OBZ being active ingredients of insect repellent and sunscreen, respectively. To assess the reported enhancing effect directly, we used human urinary metabolites as biomarkers; besides, we also sought to determine the best way for concurrent use of these two products without extra absorption of either. Four dermal application methods were used: DEET only (S1), OBZ only (S2), DEET on top of OBZ (S3), and OBZ on top of DEET (S4). Among the study methods, there was a significant difference (p = 0.013), which was attributed to the difference between S1 and S4, suggesting that applying OBZ over DEET on the skin lead to significantly higher absorption of DEET. Using both products in reverse order, (S3) did not result in extra DEET absorption significantly. As for OBZ permeation, no significant difference was observed among the methods. In summary, the enhancement of DEET absorption is confirmed for OBZ being applied over DEET on the skin; should concurrent use of both be necessary, applying sunscreen (OBZ) first and then insect repellent (DEET) with a 15-min interval is recommended.