Assessment of Efficiency of Repellent Formulations with N,N‐diethyl‐m‐toluamide in Laboratory Conditions

Abstract

The affinity of N,N-diethyl-m-toluamide) (DEET) for various polymers that are potential inert carriers (PEG, PVP, NaCMC, PAA) was studied. Mixtures of DEET and the polymers were prepared and analysed for DEET vapour release using head space analysis. Polyvinylpyrrolidone (PVP) showed the highest affinity for DEET. Several insect repellent formulations in the form of a hydrogel, an o/w cream and a stick were prepared with 5% w/w DEET and either 1% w/w or no PVP. The release of DEET from the formulations was investigated by Head Space gas-mass spectrometry at 32 degrees C. The degree of absorption of DEET through the skin was evaluated by applying these topical preparations to shaved rabbit skin and measuring DEET content in the blood samples by gas-mass spectrometry at various time intervals after application. Based on these results the pharmacokinetic parameters were determined. The minimum penetration of DEET through rabbit skin was obtained with a hydrogel containing PVP as a carrier. The biological efficiency of repellent formulations containing 5% DEET (w/w) was evaluated for repellency using the mosquito Aedes aegypti. The results demonstrated that the hydrogel formulation based on polyacrylic acid containing 5% DEET (w/w) supplemented with 1% PVP (w/w), could serve as a suitable vehicle for repellent preparations containing DEET.

Gel Carriers for Plant Extracts and Synthetic Pesticides in Rodent and Arthropod Pest Control: An Overview

“…Therefore, in this much more general review, we limited ourselves to providing a few examples regarding the development of hydrogel mosquito repellent formulations. For example, Milutinović et al [ 76 ] demonstrated that the hydrogel formulation based on polyacrylic acid containing 5% DEET ( w / w ) could serve as a suitable vehicle for repellent preparations containing DEET, and Pinto et al [ 77 ] characterized a new repellent formulation based on nanostructured hydrogels. Delong et al [ 78 ] screened various natural extracts in order to develop a new hydrogel formulation (pHEMA hydrogels with pendant triazinyl-β-cyclodextrin) containing repellents of plant origin, which may provide a suitable, eco-friendly approach to achieving mosquito bite protection.…”

Guia Atualizado sobre Atividades Profissionais Confiáveis (APCs)

“…It was only after the establishment of a massive increase in postgraduate training after World War II, and the need to define educational goals in higher education, 2 that outcome-and competency-based education became a guiding principle for medical educators. [3][4][5] Competency-based medical education was adopted in different countries in the 1990s and early 21 st century and its structure has been used to describe the full amplitude of the medical profession in terms of competencies. [6][7][8][9][10] Particularly in postgraduate training, professional associations such as the Royal Colleges were uncomfortable with the model according to which, within a certain period of time, license to practice would be automatically achieved without any rigorous assessment of training competency.…”

Insect repellents - transmissive disease vectors prevention

“…DEET serves as an effective repellent against mosquitoes, ticks and other arthropods when used on the skin and clothing 38,39 . DEET is available in repellent preparation concentrations ranging from 5% to 100% although most products contain less than 40%, as the concentration increases with a plateau at 50% 40,41 (Table 2).…”