Desenvolvimento de nanopartículas de zeína contendo repelentes visando controle do mosquito Aedes Aegypti
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Data
2019-03-01
Autores
Miranda, Vanessa Regina
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Universidade Estadual Paulista (Unesp)
Resumo
Considerando os danos causados pelas arboviroses disseminadas pelo vetor Aedes aegypti, o Brasil vem sofrendo, porém buscando estratégias de combate a tal realidade, uma vez que teve um custo total de R$ 2,3 bilhões, apenas no ano de 2016, distribuídos no combate ao vetor, em inseticidas e larvicidas e nos custos diretos e indiretos. Valor esse, correspondente a cerca de 2 % do montante investido na Saúde no mesmo ano. Esse quadro ressalta a necessidade de novas ações e táticas na procura de minimizar a situação, como a elaboração de repelentes que possuam um sistema mais efetivo no combate do vetor responsável pela disseminação do vírus Zika, da Dengue, do Chikungunya e da Febre Amarela. Hoje, sabe-se que um dos ativos repelentes mais eficientes é a icaridina, porém, ela pode causar intoxicação nos organismos não alvos. Também, tem-se o geraniol, que é um ativo de origem botânica, bastante eficaz em sua atuação repelente. E, na busca de aprimorar a ação dos ativos, existe a opção da utilização de sistemas de liberação lenta, o que resulta no aumento da faixa de efeito biológico do ativo de interesse, devido ao prolongamento da liberação do mesmo. No entanto, nota-se a existência de intensa preocupação e responsabilidade na elaboração de sistemas que, além de se mostrarem mais eficientes, sejam, também, focados na diminuição de possíveis mecanismos de resistência que o vetor possa desenvolver. Dessa forma, o presente estudo teve por objetivo o desenvolvimento de sistemas de liberação sustentada com o emprego de nanopartículas de zeína em uma mistura que contém a icaridina e o geraniol, encapsulados individualmente. Ressaltando que se realizou o estabelecimento de concentrações que fossem mais eficazes e, possivelmente, menos tóxicas em organismos não alvos. Para tanto, foram acompanhadas durante o período de tempo de sessenta dias as características físico-químicas das formulações, como, potencial zeta, polidispersão, eficiência de encapsulação, diâmetro, além da cinética de liberação, acompanhada por 40 horas. Assim, se obteve uma eficiência de encapsulação individual de cada ativo, de 98 e 80 % para formulações que continham geraniol e icaridina, respectivamente. Salienta-se, que o tamanho médio inicial foi de 206 ± 4 nm, e o potencial zeta positivo para todas as formulações, com índice de polidispersão em torno de 0,2 a 0,4. Os resultados da cinética de liberação mostraram que as formulações possuem uma intensa liberação inicial, com uma liberação sustentada com o decorrer das horas, fazendo-se adequada à finalidade de um repelente nanoencapsulado, garantindo eficiência imediata e ao longo do tempo de ação. Assim, observa-se que as nanoformulações com os dois ativos se mantiveram estabilizadas no tempo de acompanhamento de 60 dias, o que indica que a zeína é uma efetiva opção no carreamento dos ativos combinados.
Considering the damage caused by arboviruses disseminated by the vector Aedes aegypti, Brazil has been suffering, but seeking strategies to combat this reality, since it had a total cost of R$ 2.3 billion, only in the year 2016, distributed in combat to the vector, in insecticides and larvicides and in direct and indirect costs. This amount corresponds to approximately 2 % of the amount invested in Health in the same year. This scenario highlights the need for new actions and tactics in order to minimize the situation, such as the elaboration of repellents that have a more effective system in the fight against the vector responsible for the spread of the Zika virus, Dengue, Chikungunya and Yellow Fever. It is now known that one of the most effective repellent actives is icaridin, but it can cause intoxication in non-target organisms. Also, one has the geraniol, that is an active of botanical origin, quite effective in its action repellent. And, in the search to improve the action of the assets, there is the option of using slow release systems, which results in the increase of the biological effect range of the asset of interest, due to the prolongation of the release of the same. However, we note the existence of intense concern and responsibility in the elaboration of systems that, in addition to being more efficient, are also focused on the reduction of possible mechanisms of resistance that the vector can develop. Thus, the present study aimed at the development of sustained release systems with the use of zein nanoparticles in a mixture containing icaridin and geraniol, individually encapsulated. Noting that concentrations were established that were more effective and possibly less toxic in non-target organisms. The physical-chemical characteristics of the formulations, such as zeta potential, polydispersity, encapsulation efficiency, diameter, and release kinetics were monitored during the 60-day period. Thus, an individual encapsulation efficiency of each active was obtained, of 98 and 80% for formulations containing geraniol and icaridin, respectively. It should be noted that the initial mean size was 206 ± 4 nm and the zeta potential positive for all formulations, with a polydispersity index of about 0.2 to 0.4. The results of the release kinetics showed that the formulations have an intense initial release, with sustained release over the hours, making it suitable for the purpose of a nanoencapsulated repellent, guaranteeing immediate efficiency and over time of action. Thus, it is observed that the nanoformulations with the two actives remained stable at the 60-day follow-up time, which indicates that zein is an effective option in the combined assets.
Considering the damage caused by arboviruses disseminated by the vector Aedes aegypti, Brazil has been suffering, but seeking strategies to combat this reality, since it had a total cost of R$ 2.3 billion, only in the year 2016, distributed in combat to the vector, in insecticides and larvicides and in direct and indirect costs. This amount corresponds to approximately 2 % of the amount invested in Health in the same year. This scenario highlights the need for new actions and tactics in order to minimize the situation, such as the elaboration of repellents that have a more effective system in the fight against the vector responsible for the spread of the Zika virus, Dengue, Chikungunya and Yellow Fever. It is now known that one of the most effective repellent actives is icaridin, but it can cause intoxication in non-target organisms. Also, one has the geraniol, that is an active of botanical origin, quite effective in its action repellent. And, in the search to improve the action of the assets, there is the option of using slow release systems, which results in the increase of the biological effect range of the asset of interest, due to the prolongation of the release of the same. However, we note the existence of intense concern and responsibility in the elaboration of systems that, in addition to being more efficient, are also focused on the reduction of possible mechanisms of resistance that the vector can develop. Thus, the present study aimed at the development of sustained release systems with the use of zein nanoparticles in a mixture containing icaridin and geraniol, individually encapsulated. Noting that concentrations were established that were more effective and possibly less toxic in non-target organisms. The physical-chemical characteristics of the formulations, such as zeta potential, polydispersity, encapsulation efficiency, diameter, and release kinetics were monitored during the 60-day period. Thus, an individual encapsulation efficiency of each active was obtained, of 98 and 80% for formulations containing geraniol and icaridin, respectively. It should be noted that the initial mean size was 206 ± 4 nm and the zeta potential positive for all formulations, with a polydispersity index of about 0.2 to 0.4. The results of the release kinetics showed that the formulations have an intense initial release, with sustained release over the hours, making it suitable for the purpose of a nanoencapsulated repellent, guaranteeing immediate efficiency and over time of action. Thus, it is observed that the nanoformulations with the two actives remained stable at the 60-day follow-up time, which indicates that zein is an effective option in the combined assets.
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Palavras-chave
Aedes aegypti, Nanopartículas, Liberação lenta, Zeína, Icaridina, Geraniol, Nanoparticles, Slow release, Zein, Icaridin