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Authors
Abstract(s)
O estudo da solubilidade de compostos pouco solúveis em líquidos reveste-se de
grande importância em diversos contextos nas áreas farmacêutica, alimentar ou
ambiental. Na área ambiental, a solubilidade de pesticidas em água é um parâmetro
relevante na avaliação do seu impacto ambiental e no desenvolvimento de alternativas de
descontaminação. Neste contexto, o principal objetivo deste trabalho foi a implementação
de uma metodologia experimental para medição de solubilidades de compostos pouco
solúveis em água aplicando uma variante do método analítico do frasco agitado, com
membranas de diálise. Primeiramente, validou-se a metodologia utilizando o bifenilo
como composto modelo. Depois, mediu-se a solubilidade aquosa de cinco pesticidas
(carbaril, difenamida, diuron, propaclor e propanil) a 25 e 40 °C, obtendo-se em geral
resultados consistentes com a escassa informação disponível na literatura.
Na área farmacêutica, o aumento da solubilidade de compostos pouco solúveis em
água poderá ser alcançado, por exemplo, através da adição de solventes orgânicos ou de
ciclodextrinas que promovam a formação de complexos solúveis em água. Neste trabalho,
o composto escolhido foi um ácido fenólico, o ácido trans-cinâmico, com diversas
atividades biológicas e farmacêuticas. Assim, mediu-se a solubilidade deste ácido em
solventes mistos água + metanol e água + etanol, a 25 °C. Verificou-se um aumento da
solubilidade do ácido trans-cinâmico de 27,5 vezes em metanol puro e 162 vezes em etanol
puro. De forma complementar, os estudos preliminares de complexação com α-
ciclodextrina realizados, permitiram demonstrar que a solubilidade aumentou até 7,4 vezes,
com um diagrama de fases de solubilidade do tipo B
The study of the solubility of poorly soluble compounds in liquids is of great importance in diverse contexts in the pharmaceutical, food or environmental areas. In the environmental area, the solubility of pesticides in water is a relevant parameter to evaluate their environmental impact and develop decontamination alternatives. In this context, the main objective of this work was the implementation of an experimental methodology for the solubility measurement of poorly soluble compounds in water by applying a variant of the shake flask analytical method, using dialysis membranes. First, the methodology was validated using biphenyl as the model compound. Then, the aqueous solubility of five pesticides (carbaryl, diphenamid, diuron, propachlor and propanil) was measured at 25 and 40 ºC, and, in general, the results obtained were consistent with the scarce information available in the literature. In the pharmaceutical field, increasing the solubility of poorly water soluble compounds can be achieved, for example, by the addition of organic solvents or the formation of water soluble complexes with cyclodextrins. In this work, the selected compound was a phenolic acid, the trans-cinnamic acid, with various biological and pharmaceutical activities. Thus, the solubility of this acid in the mixed solvents water + methanol and water + ethanol was measured at 25 ° C. The solubility of the trans-cinnamic acid was 27.5 times higher in pure methanol and 162 times in pure ethanol than in water. Additionally, the preliminary studies regarding α-cyclodextrin complexation showed that the solubility increased up to 7.4 times, with a type B solubility phase diagram
The study of the solubility of poorly soluble compounds in liquids is of great importance in diverse contexts in the pharmaceutical, food or environmental areas. In the environmental area, the solubility of pesticides in water is a relevant parameter to evaluate their environmental impact and develop decontamination alternatives. In this context, the main objective of this work was the implementation of an experimental methodology for the solubility measurement of poorly soluble compounds in water by applying a variant of the shake flask analytical method, using dialysis membranes. First, the methodology was validated using biphenyl as the model compound. Then, the aqueous solubility of five pesticides (carbaryl, diphenamid, diuron, propachlor and propanil) was measured at 25 and 40 ºC, and, in general, the results obtained were consistent with the scarce information available in the literature. In the pharmaceutical field, increasing the solubility of poorly water soluble compounds can be achieved, for example, by the addition of organic solvents or the formation of water soluble complexes with cyclodextrins. In this work, the selected compound was a phenolic acid, the trans-cinnamic acid, with various biological and pharmaceutical activities. Thus, the solubility of this acid in the mixed solvents water + methanol and water + ethanol was measured at 25 ° C. The solubility of the trans-cinnamic acid was 27.5 times higher in pure methanol and 162 times in pure ethanol than in water. Additionally, the preliminary studies regarding α-cyclodextrin complexation showed that the solubility increased up to 7.4 times, with a type B solubility phase diagram
Description
Mestrado com dupla diplomação com a Universidade Tecnológica Federal do Paraná
Keywords
Solubilidade Pesticidas Ácido trans-cinâmico A-ciclodextrina