Caracterização, modelagem e aplicação de novos sistemas aquosos bifásicos micelares no estudo de partição de flavonoides

Abstract

Aqueous two-phase micellar systems (ABMSs) were targets of investigation in this work, evidencing their potential in partitioning molecules with a highly hydrophobic character. In this sense, new ABMSs formed by Triton X-100 + PEO (10,000 or 35,000) were evaluated at temperatures of 10, 25 and 40 ºC. It was observed that the top phase is enriched in polymer while the botton phase is rich in surfactant. The effect of composition, molar mass of PEO and temperature on the composition of the components of each phase were evaluated. From the diagrams data, an increase in the biphasic region was observed with increasing temperature, indicating that the phase separation process is endothermic. In addition, there was an increase in the biphasic region with the increase in the molar mass of PEO. Subsequently, the balance data and the binodal curves were adjusted to the linear expressions Othmer-Tobias, Bancroft, Hand and Setschenow and applied to the Flory-Huggins model. All models showed a significant correlation between data at a 5% significance level with correlation coefficients greater than 0.90. The microscopic aspect of the polymer-surfactant interaction was studied with the Cloud Point, DLS, and 1H NMR techniques. The techniques allowed to infer how the polymer affects the formation of aggregates in solution and therefore a PEO/Triton interaction model was proposed. The results showed that the PEO segments significantly increase the size of the aggregates and affect both the hydrophilic and hydrophobic parts of the micelles. The raised diagrams were applied to the partition of the naringin, rutin and quercetin flavonoids. In the partition study, the effect of ILA, molar mass of PEO and surfactant on the transfer process of flavonoids between the phases of ABMS was evaluated. All studies indicated partition coefficients below 1, showing the migration of flavonoids towards the surfactant-rich phase. It was observed that for all ILA values, the extraction efficiency of the flavonoids was higher than 84%, reaching in some cases 99%. The increase in the molar mass of the polymer favored the migration of the three flavonoids to the lower phase, being Kf (PEO 35,000> PEO 20,000> PEO 10,000> PEO 4,000). Comparing the surfactants Triton X-100 and Tween 80, the first showed a greater potential in partitioning the studied flavonoids with an increased percentage of extraction that varied from 10 to 15% for similar equilibrium compositions.