Tautomeric and Aggregational Dynamics of Curcumin-Supersaturated Pluronic Nanocarriers

The comprehension of the tautomeric and aggregation dynamics of curcumin (Cur) is fundamental to predict clinical responses and to develop biomedical materials in drug delivery science. Although several studies have explored the dynamics of biologically active agents incorporated into drug delivery systems, little information about the influence of these pharmaceutical systems on the tautomeric and aggregation profile of Cur in supersaturated conditions is known. In the present study, HF-3c and B3LYP/6-31+G(d,p) levels of theory were applied to investigate the stabilization capacity of tautomeric components in the micellar blocks of Pluronics F127 and P123. Additionally, the computational modeling provided molecular orbital and theoretical spectra of the components, either after interaction with copolymeric segments or aggregational processes, which is fundamental to understand the critical packing parameters (CPPs) of these materials influenced by Cur incorporation. "Digital chromatography" by multivariate curve resolution-alternating least squares has been explored to obtain the spectra of the pure species under experimental conditions. Scanning and transmission electron microscopy analyses allowed the visualization of Pluronics dynamics related to self-association behavior and their dependence on Cur interaction. Molecular modeling results have shown that Keto tautomer can interact with both hydrophilic poly(ethylene oxide) (PEO) and hydrophobic poly(propylene oxide) blocks comprised of Pluronics. These results suggest that alterations in CPP parameters lead to an increase of hydrophobicity in the cross-sectional area of the PEO block, the most outstanding in F127 copolymer. Therefore, it is possible to see that the changes in CPP parameters lead to an increase in the hydrophobicity in the cross-sectional area of the most prominent PEO block in the copolymer F127. There is a strong evidence for the coexistence of complex structures resulting from the interaction between the copolymeric self-association and Cur, which allows us to get a better insight into the architecture of these copolymeric systems when incorporated with hydrophobic compounds.