Preparação de coacervatos e suas aplicações como materiais multifuncionais
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Data
2022-04-19
Autores
Paiva, Juliana Moreno de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os fosfatos ou ortofosfatos são íons que apresentam a capacidade de formar um polímero inorgânico comumente chamado de polifosfato. Dentre eles destaca-se o polifosfato de sódio por ter simplicidade química, alta solubilidade em água, com relativa estabilidade e degradação mínima, resultando em uma solução de cadeias inorgânicas de polifosfato. Com essa solução é possível formar os coacervatos de polifosfato (CPPs), uma substância amorfa insolúvel em água que pode ser obtida pela adição cátions metálicos, como Ca2+, que permitem interações supramoleculares entre cadeias polifosfáticas adjacentes em solução. Nesse trabalho, é relatado a síntese e caracterização de coacervatos de polifosfato de cálcio com três diferentes razões [P]:[Ca] como novas matrizes para liberação de fármacos. Foram utilizados os fármacos clorexidina, que possui ação antibactericida, e a cafeína, que além de ser estimulante e analgésica é muito utilizada em formulações cosméticas. O estudo de incorporação e liberação do fármaco foi feito empregando a espectroscopia na região do Ultra-Violeta-Visível (UV-Vis). O aumento a concentração de Ca2+ nos coacervatos aumentou a eficiência de incorporação sendo de 95,4% para cafeína e 70,4% para clorexidina. Durante a liberação os fármacos apresentaram resultados diferentes. A cafeína seguiu um modelo de liberação similar ao de Weibull, enquanto a clorexidina associou-se melhor ao modelo de Korsmeyer-Peppas. A partir dos espectros na região do infravermelho (IV) e Raman foi possível observar ligações de hidrogênio do coacervato com clorexidina e interações de Van der Walls com a cafeína. Além disso, a diferença de tamanho entre as moléculas e as estruturas semelhantes a gaiolas formadas durante o processo de coacervação também foram responsáveis pelas diferenças. Por fim, e considerando o desempenho desses materiais, junto a suas propriedades biocompatíveis, bioabsovíveis, de síntese fácil, baixo custo a temperatura ambiente, entende-se que estes Ca-CPPs são promissores para serem utilizados como sistemas de liberação de fármacos.
Phosphates or orthophosphates are ions that have the ability to form an inorganic polymer commonly called polyphosphate. Among them, sodium polyphosphate stands out for its chemical simplicity, high water solubility, relative stability and minimal degradation, resulting in a solution of inorganic polyphosphate chains. With this solution, it is possible to form polyphosphate coacervates (PPCs), an amorphous substance insoluble in water that can be obtained by adding metal cations, such as Ca2+, which allow supramolecular interactions between adjacent polyphosphate chains in solution. In this work, the synthesis and characterization of calcium polyphosphate coacervates with three different [P]:[Ca] ratios as novel matrices for drug delivery is reported. The drugs chlorhexidine, which has antibacterial action, and caffeine, which besides being a stimulant and analgesic, are widely used in cosmetic formulations were used. The study of drug incorporation and release was carried out using spectroscopy in the Ultra-Violet-Visible (UV-Vis) region. Increasing the concentration of Ca2+ in coacervates increased the efficiency of incorporation being 95.4% for caffeine and 70.4% for chlorhexidine. During release, the drugs showed different results. Caffeine followed a release model similar to that of Weibull, while chlorhexidine was better associated with the Korsmeyer-Peppas model. From the infrared (IR) and Raman spectra, it was possible to observe hydrogen bonds between coacervate and chlorhexidine and Van der Walls interactions with caffeine. Furthermore, the size difference between the molecules and the cage-like structures formed during the coacervation process were also responsible for the differences. Finally, and considering the performance of these materials, together with their biocompatible, bioabsorbable, easily synthesized, low cost at room temperature properties, it is understood that these Ca-CPPs are promising to be used as drug delivery systems.
Phosphates or orthophosphates are ions that have the ability to form an inorganic polymer commonly called polyphosphate. Among them, sodium polyphosphate stands out for its chemical simplicity, high water solubility, relative stability and minimal degradation, resulting in a solution of inorganic polyphosphate chains. With this solution, it is possible to form polyphosphate coacervates (PPCs), an amorphous substance insoluble in water that can be obtained by adding metal cations, such as Ca2+, which allow supramolecular interactions between adjacent polyphosphate chains in solution. In this work, the synthesis and characterization of calcium polyphosphate coacervates with three different [P]:[Ca] ratios as novel matrices for drug delivery is reported. The drugs chlorhexidine, which has antibacterial action, and caffeine, which besides being a stimulant and analgesic, are widely used in cosmetic formulations were used. The study of drug incorporation and release was carried out using spectroscopy in the Ultra-Violet-Visible (UV-Vis) region. Increasing the concentration of Ca2+ in coacervates increased the efficiency of incorporation being 95.4% for caffeine and 70.4% for chlorhexidine. During release, the drugs showed different results. Caffeine followed a release model similar to that of Weibull, while chlorhexidine was better associated with the Korsmeyer-Peppas model. From the infrared (IR) and Raman spectra, it was possible to observe hydrogen bonds between coacervate and chlorhexidine and Van der Walls interactions with caffeine. Furthermore, the size difference between the molecules and the cage-like structures formed during the coacervation process were also responsible for the differences. Finally, and considering the performance of these materials, together with their biocompatible, bioabsorbable, easily synthesized, low cost at room temperature properties, it is understood that these Ca-CPPs are promising to be used as drug delivery systems.
Descrição
Palavras-chave
Coloides, Polifosfato, Fármacos, Cafeína, Clorexidina