The paper presents
the contribution of the cocrystallization method in the physicochemical
modification of catechins that exhibit low oral bioavailability. This
was done to obtain cocrystals for two naturally occurring polyphenolic
diastereoisomers (+)-catechin and (−)-epicatechin with commonly
used coformers. Due to distinct crystallization behavior, only the
(−)-epicatechin cocrystal with barbituric acid in a 1:1 stoichiometry
was obtained. The cocrystal of (−)-epicatechin (EC) with barbituric
acid (BTA) was prepared by the slow solvent-evaporation technique.
The structure and intermolecular interactions were determined by X-ray
crystallographic techniques. The analysis of packing and interactions
in the crystal lattice revealed that molecules in the target cocrystal
were packed into tapes, formed by the O–H···O
type contacts between the (−)-epicatechin and coformer molecules.
The EC molecules interact with the carboxyl group in the BTA coformer
mainly by −OH groups from the benzene ring A. The cocrystalline
phase constituents were also investigated in terms of Hirshfeld surfaces.
The application of Raman spectroscopy confirmed the involvement of
the CO group in the formation of hydrogen bonds between the
(−)-epicatechin and barbituric acid molecules. Additionally,
the solubility studies of pure EC and the EC-BTA cocrystal exhibited
minor enhancement of EC solubility in the buffer solution, and pH
measurements confirmed a stable level of solubility for EC and its
cocrystal.
The main purpose of the research was to obtain and study hybrid materials based on three different nano-oxides commonly used in the cosmetic and pharmaceutical industries: Al2O3, TiO2, and ZnO, with the natural bioactive polysaccharide fucoidan. Since the mentioned oxides are largely utilized by industry, there is no doubt that the presented studies are important from an environmental point of view. On the basis of the textural studies (dynamic light scattering DLS, low temperature nitrogen adsorption, X-ray diffraction analysis XRD, scanning electron microscopy SEM) it was proved that the properties of the hybrid materials differ from the pure components of the system. Moreover, the advanced thermal analysis (TG-DTG-DSC) combined with the evolved gas analysis using Fourier transformed infrared spectroscopy (FTIR) and mass spectrometry were applied to describe the thermal decomposition of fucoidan, oxides and hybrid materials. It was found that the interactions between the polymer and the oxides results in the formation of the hybrid materials due to the functionalization of the nanoparticles surface, and that their thermal stability increased when compared to the pure substrates. Such findings definitely fill the literature void regarding the fucoidan based hybrid materials and help the industrial formulators in the preparation of new products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.