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[pt] Atualmente a crescente demanda do uso de repelentes de insetos tem promovido a pesquisa de produtos mais eficazes e com uma maior durabilidade da ação repelente. O objetivo deste trabalho foi a obtenção de novas nanopartículas com propriedades interfaciais modificadas superficialmente com grupos funcionais catiônicos e polímeros aniônicos, com o intuito de melhorar a estabilidade de emulsões Pickering contendo um princípio ativo, N,N -dimetil-m-toluamida (DEET), comumente utilizado nos repelentes comerciais. A obtenção das nanopartículas incluiu a funcionalização inicial da superfície de nanopartículas de sílica comerciais com grupos amino secundários (R-NH2), seguido da introdução de grupos catiônicos de amônio quaternário (R-NR4 positivo) e posterior complexação eletrostática com polímeros aniônicos (poli(ácido acrílico), PAA, e poli(4-estireno sulfonato de sódio), PSS). As nanopartículas modificadas mostraram boa dispersabilidade em meio aquoso, favorecendo a estabilização de emulsões de tipo óleo em água (O/A). Os melhores resultados dos estudos de estabilidade no tempo das emulsões foram obtidos usando as nanopartículas catiônicas (SiNP-A,G) recobertas com PAA e com a mistura de polímeros (PAA mais PSS). As emulsões Pickering obtidas com as nanopartículas de sílica recobertas com PAA mostraram os melhores resultados na retardação da evaporação do DEET, com potencial uso para liberação lenta deste composto. / [en] Currently the increasing demand for insect repellent use has promoted research into more effective products and a longer repellent action. The objective of this work was to obtain new nanoparticles by surface modification with cationic functional groups and anionic polymers, with the aim of improving the stability of Pickering emulsions containing an active ingredient, N,N -diethyl-m-toluamide (DEET) commonly used in commercial repellents. The preparation of the nanoparticles included initial surface functionalization of commercial silica nanoparticles with secondary amino groups (R-NH2), followed by the introduction of cationic quaternary ammonium groups (R-NR4 positive) and subsequent electrostatic complexation with anionic polymers (poly (acrylic acid), PAA, and poly(sodium 4-styrenesulfonate), PSS). The modified nanoparticles showed good dispersibility in aqueous medium, favoring the stabilization of emulsions oil-in-water (O/W). The best results of the emulsion time stability studies were obtained using cationic silica nanoparticles (SiNP-A,G) covered with PAA and with the polymer mixture (PA plus PSS). The Pickering emulsions obtained with the cationic silica nanoparticles coated with PAA showed the best results in retarding DEET evaporation, with potential use for slow release of this compound.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-02-04T11:45:28Z No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-02-05T14:22:22Z (GMT) No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-02-05T14:22:22Z (GMT). No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-14 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Ticks are arthropods of great importance in public health, due to the transmission of many pathogens. Rhipicephalus sanguineus parasites mainly dogs. It is known that Beagle dogs are less susceptible to R. sanguineus than English Cocker Spaniel, and still have resistance patterns linked to immunity. The lower susceptibility of Beagle dogs is due to chemical compounds they produce, which act in reducing the parasitic load of R. sanguineus on these animals. Given that this research aimed to verify the chemical repellency against R. sanguineus of compounds that have been identified in the odor of resistant dogs, and synthetic repellent compounds to other tick species. For testing chemical repellency two tests were used, the Petri dish and the Y-olfactometer. Five compounds identified in Beagle odors were selected and tested: 2 - hexanone, nonane, decane, undecane and benzaldehyde, the compound of botanical origin β-citronellol and the standard repellent DEET (N,N-diethyl-3-methylbenzamide). These compounds were tested alone and also two mixtures were evaluated: benzaldehyde and 2-hexanone (1:1), and benzaldehyde, 2-hexanone and undecane (1:1:1). All these compounds were prepared in a stock solution of 7.2 % ( ≈ 0.200 mg/cm²) and two lower concentrations were also tested: 0.100 and 0.050 mg/cm². DEET was repellent in the two highest concentrations and 68.33 to 86.67% of the ticks were found in untreated areas in different time points. At the concentration of 0.050 mg/cm² ticks were distributed similarly (without significant difference) in both areas. β-citronellol was the only compound tested that was repellent at all times and concentrations tested. The percentage of ticks in untreated areas ranged from 73.33 to 93.33 %. When compared β-citronellol with DEET the first compound was more effective at repelling the adults of R. sanguineus. For benzaldehyde, 30 minutes at a concentration of 0.200 mg/cm² a percentage of 63.33 % of ticks was observed in the untreated area. Percentage of 76.67 was observed after 5 min. at a concentration of 0.050 mg/cm². 2-hexanone was repellent at 30 min. at a concentration of 0.200 mg/cm² at 10 min. at a concentration of 0.100 mg/cm² and 30 minutes at a concentration of 0.050 mg/cm². For undecane a rate of 65.00% of ticks was observed in the untreated area in one moment of testing, the highest concentration during the first 5 min. of the evaluation. Nonane and decane not were not repellent at any of the concentrations and time intervals. The blend benzaldehyde + 2-hexanone was repellent in the three highest concentrations in almost all evaluated times, including in the olfactometer testing. During the whole test this mixture showed statistical similarity when compared with DEET. The addition of undecane to this blend did not potentiate its repellent power. The main result was the finding of natural repellents in resistant dogs to the tick R. sanguineus. / Carrapatos são artrópodes de grande importância dentro da saúde pública, devido à transmissão de inúmeros patógenos. Rhipicephalus sanguineus parasita principalmente cães. Sabe-se que cães da raça Beagle são menos susceptíveis ao R. sanguineus que cães Cocker Inglês, e ainda apresentam padrões de resistência ligados a imunidade. A menor susceptibilidade de cães Beagle está ligada a compostos químicos que estes produzem, os quais atuam na diminuição da carga parasitária de R. sanguineus sobre estes animais. Sabendo-se disso com esta pesquisa objetivou-se verificar a repelência química de compostos que foram identificados no odor de cães resistentes, além de compostos sintéticos repelentes para outros carrapatos, contra o R. sanguineus. Para os testes de repelência química foram utilizados dois ensaios de repelência, o da placa de Petri e do olfatômetro em Y. Foram testados cinco compostos com provável poder repelente e identificados nos odores de Beagle (2-hexanona, nonano, decano, undecano e benzaldeído), o composto de origem botânica β-citronelol e o repelente padrão DEET (N,N-dietil-3-metilbenzamida). Além destes compostos testados isoladamente, duas misturas foram avaliadas: benzaldeído e 2 -hexanona (1:1), e benzaldeído, 2-hexanona e undecano (1:1:1) Todos estes compostos foram formulados a partir de uma solução mãe de 7,2% (≈ 0,200 mg/cm²) da qual foi obtida posteriormente outras duas concentrações (0,100 e 0,050 mg/cm²). O DEET foi repelente nas duas maiores concentrações, sendo que 68,33 a 86,67% dos carrapatos foram encontrados nas áreas não tratadas, nos diferentes tempos de observação. Na concentração de 0,050 mg/cm² os carrapatos se distribuíram similarmente (sem diferença significativa) em ambas as áreas. β-citronelol foi o único composto testado que foi repelente em todos os tempos e concentrações testados. Os percentuais de carrapatos nas áreas não tratadas variaram de 73,33 a 93,33%. Quando comparado com o DEET o β-citronelol foi mais eficiente em repelir os adultos de R. sanguineus. Para o benzaldeido, aos 30 minutos, na concentração de 0,200 mg/cm² foi observado um percentual de 63,33% de carrapatos na área não tratada. Percentual de 76,67 foi observado aos cinco minutos, na concentração de 0,050 mg/cm². A 2-hexanona foi repelente aos 30 minutos, na concentração de 0,200 mg/cm², aos 10 minutos, na concentração de 0,100 mg/cm² e aos 30 minutos, na concentração de 0,050 mg/cm². Para o undecano foi observado um percentual de 65,00 de carrapatos na área não tratada em apenas um momento dos testes, na maior concentração, durante os primeiros cinco minutos de avaliação. Nonano e decano não causaram qualquer repelência para os carrapatos testados, em qualquer uma das concentrações ou intervalos de tempo avaliados. A mistura benzaldeido + 2-hexanona foi repelente nas três maiores concentrações, em quase todos os tempos avaliados, inclusive no teste de olfatometria. Durante todo o teste esta mistura mostrou semelhança estatística quando comparada com o DEET. A adição de undecano a esta mistura não potencializou o seu poder repelente. O principal resultado obtido foi a constatação da presença de repelentes naturais em cães resistentes ao carrapato R. sanguineus.

[pt] Os mosquitos são os principais vetores de transmissão de doenças como zika, dengue e chikungunya, causando mais de 700 mil casos por ano. O uso de repelentes, principalmente formulações tópicas, é uma das melhores medidas de proteção para reduzir e/ou prevenir a transmissão de muitas doenças transmitidas por insetos. Neste trabalho, formulamos emulsões de DEET/óleo em água para liberação controlada de repelentes como estratégia para desenvolver formulações repelentes com tempo de proteção superior a 6 h. Investigamos os efeitos do valor de HLB na estabilidade e viscosidade das emulsões, usando uma mistura de surfactantes (Span 80 e Tween 80) para formular emulsões em uma faixa de HLB entre 4-14. Também avaliamos o tamanho das gotas, comportamento reológico, método de mistura e índice de estabilidade da emulsão. As emulsões de DEET-óleo-em-água desenvolvidas contendo N, N-dietil-3-metilbenzamida (DEET) foram estabilizadas usando dois nanomateriais carregados negative e positivamente, nanopartículas de sílica (SiNP) e nanofibrilas de celulose catiônica (CCNF), e uma mistura de surfactantes não iônicos de grau para evitar a precipitação por agregação eletrostática. Os resultados indicam que no HLB 10, esta mistura pode estabilizar as emulsões independentemente do tipo de óleo (mineral ou vegetal), e as emulsões apresentam comportamento newtoniano independentemente do método de mistura. As formulações foram estáveis por mais de quatro meses à temperatura ambiente, mostrando-se fortemente resistentes à desestabilização por estresse centrífugo e térmico quando se utiliza nanomateriais em combinação com surfactantes. O CCNF e o SiNP mantiveram a distribuição granulométrica estável devido ao aumento da viscosidade da fase contínua. A ação combinada desses materiais na estabilização da fase oleosa contendo DEET diminuiu significativamente a taxa de liberação do composto ativo em comparação com o DEET não emulsificado, produzindo uma liberação sustentada de DEET nas primeiras 6 h. / [en] Mosquitoes are the main vectors of transmission of diseases such as zika, dengue and chikungunya, causing more than 700,000 cases per year. The use of repellents, mainly topical formulations, is one of the best protective measures to reduce and/or prevent the transmission of many insect-borne diseases. In this work, we formulated DEET/oil-in-water emulsions for the controlled release of repellents as a strategy to develop repellent formulations with a protection time greater than 6 h. We investigated the effects of the HLB value on the stability and viscosity of the emulsions, using a blend of surfactants (Span 80 and Tween 80) to formulate emulsions in an HLB range between 4-14. We also evaluated droplet size, rheological behavior, mixing method and emulsion stability index. The developed DEET-oil-in-water emulsions containing N, N-diethyl-3-methylbenzamide (DEET) were stabilized using two positively and negative charged nanomaterials, silica nanoparticles (SiNP) and cationic cellulose nanofibrils (CCNF), and a blend of food-grade nonionic surfactants to prevent precipitation by electrostatic aggregation. The results indicate that at HLB 10, this mixture can stabilize the emulsions regardless of the type of oil (mineral or vegetable), and the emulsions present Newtonian behavior regardless of the mixing method. The formulations were stable for more than four months at room temperature, showing to be strongly resistant to destabilization by centrifugal and thermal stress when using nanomaterials in combination with surfactants. The CCNF and SiNP kept the droplet size distribution stable due to the increase in the viscosity of the continuous phase. The combined action of these materials in stabilizing the DEET-containing oil phase significantly decreased the rate of active compound release compared to non-emulsified DEET, producing a sustained release of DEET within the first 6 h.

Insect repellent N,N-diethyl-m-toluamide (DEET) and sunscreen oxybenzone are commonly incorporated into commercially available repellent and sunscreen preparations. Both compounds have demonstrated an increased percutaneous permeation and systemic disposition after concurrent application in vitro and in vivo. The permeation enhancement between DEET and oxybenzone not only compromises their respective protective efficacy against biting insects and UV radiation, but also potentiates toxicological properties in susceptible subjects. The pharmacokinetic and toxicological profiles from concurrent use of DEET and oxybenzone were evaluated and compared in this thesis. DEET and oxybenzone were administered by intravenous and topical routes in rats, either alone and/or in combination, to compare the pharmacokinetics of parent compounds and their primary metabolites in vivo. To evaluate toxicological characteristics, rat primary cortical neurons and astrocytes, and rat hepatoma 1548 cells were exposed to DEET, oxybenzone and their metabolites in vitro, and cell viability was analyzed. Various behavioral testing protocols were also performed to assess arousal, locomotion, habituation, and motor coordination of rats over a 30-day study period. Concurrent topical application of DEET and oxybenzone enhanced the disposition of DEET and its metabolites in rats, but did not consistently affect the distribution of oxybenzone and its metabolites. The disappearance of DEET from skin application site was accelerated; its apparent elimination half-life was decreased while its plasma and tissue concentrations were predominantly increased. Cellular toxicity occurred at 1 μg/ml for neurons and 7-day exposure for both astrocytes and neurons. Viability of hepatoma cells was also reduced when treated with DEET, oxybenzone and their metabolites, either alone or in combination, most notably after 72 hours of exposure. However, no overt signs of toxicity were observed from behavioral testing in rats after a 30-day topical study. The pharmacokinetic data obtained was beneficial in understanding and elucidating absorption and biodistribution of DEET and oxybenzone in vivo. The toxicological data suggested that the risk for increasing adverse effects from concurrent skin application of repellents and sunscreens would be low and marginal in healthy individuals. Nevertheless, further studies should be carried out to assess the long-term health impact of these compounds in susceptible subjects, especially at higher application doses.

Insect repellent N,N-diethyl-m-toluamide (DEET) and sunscreen oxybenzone are commonly incorporated into commercially available repellent and sunscreen preparations. Both compounds have demonstrated an increased percutaneous permeation and systemic disposition after concurrent application in vitro and in vivo. The permeation enhancement between DEET and oxybenzone not only compromises their respective protective efficacy against biting insects and UV radiation, but also potentiates toxicological properties in susceptible subjects. The pharmacokinetic and toxicological profiles from concurrent use of DEET and oxybenzone were evaluated and compared in this thesis. DEET and oxybenzone were administered by intravenous and topical routes in rats, either alone and/or in combination, to compare the pharmacokinetics of parent compounds and their primary metabolites in vivo. To evaluate toxicological characteristics, rat primary cortical neurons and astrocytes, and rat hepatoma 1548 cells were exposed to DEET, oxybenzone and their metabolites in vitro, and cell viability was analyzed. Various behavioral testing protocols were also performed to assess arousal, locomotion, habituation, and motor coordination of rats over a 30-day study period. Concurrent topical application of DEET and oxybenzone enhanced the disposition of DEET and its metabolites in rats, but did not consistently affect the distribution of oxybenzone and its metabolites. The disappearance of DEET from skin application site was accelerated; its apparent elimination half-life was decreased while its plasma and tissue concentrations were predominantly increased. Cellular toxicity occurred at 1 μg/ml for neurons and 7-day exposure for both astrocytes and neurons. Viability of hepatoma cells was also reduced when treated with DEET, oxybenzone and their metabolites, either alone or in combination, most notably after 72 hours of exposure. However, no overt signs of toxicity were observed from behavioral testing in rats after a 30-day topical study. The pharmacokinetic data obtained was beneficial in understanding and elucidating absorption and biodistribution of DEET and oxybenzone in vivo. The toxicological data suggested that the risk for increasing adverse effects from concurrent skin application of repellents and sunscreens would be low and marginal in healthy individuals. Nevertheless, further studies should be carried out to assess the long-term health impact of these compounds in susceptible subjects, especially at higher application doses.

Actuellement, la plupart des textiles utilisés pour limiter les contacts avec les moustiques vecteurs de maladies sont imprégnés d’insecticides pyréthrinoïdes possédant une action insecticide et répulsive. Cependant, l’apparition de résistances au sein des populations de moustiques remet en cause cette efficacité.La nouvelle stratégie de lutte contre les moustiques s’appuie sur l’effet synergique obtenu lors d’une association de deux molécules de familles chimiques différentes à effet insecticide et répulsif. Les effets de deux répulsifs, le DEET et l’IR3535 ont été étudiés sur des cellules neurosecrétrices isolées du système nerveux central de la blatte Periplaneta americana. A l’aide de la technique d’imagerie calcique, il a été possible de montrer que ces composés induisent une augmentation dose-dépendante complexe de la concentration en calcium intracellulaire. L’utilisation d’outils pharmacologiques spécifiques a permis de caractériser les cibles et les évènements moléculaires impliqués dans ces effets. A partir de ces résultats, l’IR3535 s’est avéré être le meilleur répulsif pour une association avec un insecticide néonicotinoïde, le thiaclopride. Grâce à la technique électrophysiologique du patch-clamp adaptée sur neurones d’insecte, l’effet synergique produit par l’association IR3535/thiaclopride a été observé et le rapport de concentrations répulsif/insecticide qui donne le meilleure effet synergique sur le courant entrant induit par le thiaclopride déterminé. Des tests en cône réalisés sur moustiques in vivo ont confirmé cet effet synergique,démontrant l’intérêt de proposer l’associationIR3535/thiaclopride comme nouvelle stratégie de lutte anti-vectorielle. / Today, most of the textiles used to limit contact with mosquitoes are impregnated with pyrethroid insecticides having both insecticidal and repellent activities. However, the development of resistance in mosquito populations reduces their efficacy. The new strategy proposed against mosquito-transmitted diseases is based on the potential synergy observed with the combination of two different compounds with insecticidal and repellent effects. In this context, the effects of two repellents DEET and IR3535 have been studied on neurosecretory cells isolated from the central nervous system of the cockroach Periplaneta Americana. Using calcium imaging, both DEET and IR3535 induce a dose-dependent complex elevation of intracellular calcium concentration. Specific pharmacological tools have allowed to characterize the different targets together with the molecular events involved in the repellent-induced calcium rise. From these results, it has been possible to identify IR3535 as the most suitable compound to be used in association with the insecticide neonicotinoid, thiacloprid. Using the whole-cell patch-clamp technique adapted on isolated insect neurons, the synergistic effect of the IR3535/thiacloprid mixture has been observed on the thiacloprid-induced current and the most efficient ratio between repellent and insecticide has also been determined. In addition, cone tests performed on in vivo mosquitoes confirm this synergistic effect, demonstrating that IR3535/thiacloprid mixture could bean alternative strategy in the management of chemical use against resistant mosquitoes.

Objectives: To evaluate the efficacy of commercially used insect repellents against Aedes aegypti stings. Material and Methods: Was used method standard the World Health Organization to evaluate the sensitivity of the mosquito by estimating the total protection time (TPT) of the repellent. The test consists of application of the product and introduction of the volunteer arm into cages containing 50 female mosquitoes, aged between five and seven days. The initial product was 10% technical grade N, N diethylbenzamine (DEET) and four formulations with different concentrations of DEET, OFF Family (7,125%), Baruel (9,5%), Expert Total : 1612043 and 16144314, Super Repelex Aerosol (11%), product based on IR3535 (Repeden Spray 12%, Jonsons Baby Lotion 12.5%), and the ICARIDINE base (Exposis Extreme Tetra 25%), by the median of each product in 6 volunteers, being three men and three women. Results: The OFF Family brand (DEET 7,125%), Baruel (DEET 9,5) and analytical DEET (10%) demonstrated a median of 30 minutes, even presenting different concentrations; Super Repelex Aerosol (DEET 11%) among the products containing DEET was the one that presented a higher median, with a TPT of 90 minutes; Expert Total (DEET 15%) (1st batch) and Expert Total (DEET 15%) (2nd batch) are shown with medians equal with a time of 60 minutes; Repeden Spray (IR3535 12%) and Johnsons baby (IR3535 12.5%) presented a median TPT of 60 and 30 minutes respectively, differing only in the degree of concentration of the active principle; Exposis Extreme (25% Icaridina) presented a median of 120 minutes, showing a superiority in relation to the other products. Conclusion: The products had a complete protection time lower than the one specified in their labels, and may leave the population that use them as a control measure against several unprotected diseases, requiring a greater number of reapplications of the products. / Objetivos: Avaliar a eficácia de repelentes utilizados comercialmente contra picadas de Aedes aegypti. Material e Métodos: Foi utilizado o método padrão da Organização Mundial da Saúde para avaliar a sensibilidade do mosquito através da estimativa de tempo de proteção completa (TPC) do repelente. O teste consiste na aplicação do produto e introdução do braço de voluntário em gaiolas contendo 50 mosquitos fêmeas, com idade entre cinco a sete dias. Foi avaliado inicialmente produto a base de N,N dietilbenzamina (DEET) grau técnico a 10% e quatro formulações com diferentes concentrações de DEET, OFF Family (7,125%), Baruel (9,5%), Expert Total (15%) lotes: 1612043 e 16144314, Super Repelex Aerossol (11%), produto a base de IR3535 (Repeden Spray 12%, Loção Jonsons Baby 12,5%,) e a base de ICARIDINA (Exposis Extreme Tetra 25%), e estimado o TPC pela mediana de cada produto em 6 voluntários, sendo três homens e três mulheres. Resultados: A marca OFF Family (DEET 7,125%), Baruel (DEET 9,5) e DEET analítico (10%) demostraram uma mediana de 30 minutos, mesmo apresentando diferentes concentrações; Super Repelex Aerossol (DEET a 11%), dentre os produtos contendo DEET, foi o que apresentou uma maior mediana, com TPC de 90 minutos; Expert total (DEET 15%) (1º lote) e o Expert Total (DEET 15%) (2º lote) mostram-se com medianas iguais com um tempo de 60 minutos; Repeden Spray (IR3535 12%) e Johnsons baby (IR3535 12,5%) apresentaram uma mediana com TPC de 60 e 30 minutos respectivamente, diferindo apenas no grau da concentração do princípio ativo; Exposis Extreme (Icaridina a 25%) apresentou uma mediana de 120 minutos, mostrando uma superioridade em relação aos outros produtos. Conclusão: Os produtos apresentaram tempo de proteção completa inferior a especificada em seus rótulos, podendo deixar a população que os utilizam como medida de controle contra diversas doenças desprotegida, sendo necessário maior número de reaplicações dos produtos para atingir a o período de proteção desejado. / São Cristóvão, SE