Development and Validation of a Chromatographic Method for Determining N,N-Diethyl-3-methylbenzamide (DEET) and Verifying the Quality of Topical Repellents
Vigil Sanit Debate, Rio de Janeiro, 2025, v.13: e02488| Published on: 12/12/2025
DOI:
https://doi.org/10.22239/2317-269X.02488Keywords:
DEET, HPLC-DAD, Insect Repellents, Sanitary SpecificationsAbstract
Introduction: Insect repellents are essential for protecting against bites and preventing vector-borne diseases such as dengue. N,N-Diethyl-3-methylbenzamide (DEET) is the most widely used synthetic active ingredient in these formulations. Given the importance of repellent use in the Brazilian epidemiological context, ensuring product quality and regulatory compliance is crucial. However, laboratories within the National Network of Health Surveillance Laboratories (RNLVISA) currently do not offer assays for the quantification of the active ingredients in topical repellents. Objectives: This study, conducted by the Center for Physical and Chemical Testing of Cosmetics and Disinfectants (NFQC), aimed to develop and validate a high-performance liquid chromatography method with diode array detection (HPLC-DAD) for the quantification of DEET and quality verification of commercial formulations. Method: Analyses were performed using a C8 column (125 × 4.6 mm, 5 μm), a mobile phase of acetonitrile:water (40:60 v/v), a flowrate of 1 mL/min, an injection volume of 20 μL, and detection at 210 nm. The method was validated following the ICH and AOAC guidelines and applied to six commercial samples, including one formulation imported from Australia. The active ingredient content, pH, and labeling compliance were evaluated. Results: The method demonstrated compliance with the validation parameters. Two samples showed labeling nonconformities; one sample had a pH below the manufacturer’s specification, and the other had an active ingredient content above the permitted range. Conclusions: The developed method proved suitable for the quantification of DEET, meeting the validation criteria. Its application to commercial samples revealed nonconformities related to the active content, pH, and labeling, reinforcing the need for systematic quality control measures.
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Author Biographies
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Fernanda Fernandes Farias, Programa de Pós-graduação em Medicina Translacional, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil | Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brasil | Centro de Medicamentos, Cosméticos e Saneantes, Instituto Adolfo Lutz, São Paulo, SP, Brasil
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Maria Cristina Santa Bárbara, Centro de Medicamentos, Cosméticos e Saneantes, Instituto Adolfo Lutz, São Paulo, SP, Brasil
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Mariana Sbaraglini Garcia Silva, Centro de Medicamentos, Cosméticos e Saneantes, Instituto Adolfo Lutz, São Paulo, SP, Brasil
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Vanessa Cristina Martins Silva , Centro de Medicamentos, Cosméticos e Saneantes, Instituto Adolfo Lutz, São Paulo, SP, Brasil
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Newton Andreo-Filho, Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brasil
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Patricia Santos Lopes, Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brasil
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Vânia Rodrigues Leite-Silva, Programa de Pós-graduação em Medicina Translacional, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil | Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brasil | Frazer Institute, Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia
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