RESUMO

While 2-amino-4-(4-chlorophenyl)thiazole (AT) drug and thiazole derivatives have several biological applications, these compounds present some drawbacks, such as low aqueous solubility and instability. A new complex of ßCD-AT has been synthesized to increase AT solubility and has been used as a substrate for the deposit of solid-state AuNPs via magnetron sputtering, thus forming the ßCD-AT-AuNPs ternary system, which is stable in solution. Complex formation has been confirmed through powder X-ray diffraction and 1D and 2D nuclear magnetic resonance. Importantly, the amine and sulfide groups of AT remained exposed and can interact with the surfaces of the AuNPs. The complex association constant (970 M-1) has been determined using phase solubility analysis. AuNPs formation (32 nm average diameter) has been studied by UV-Visible spectroscopy, transmission/scanning electron microscopy and energy-dispersive X-ray analysis. The in vitro permeability assays show that effective permeability of AT increased using ßCD. In contrast, the ternary system did not have the capacity to diffuse through the membrane. Nevertheless, the antibacterial assays have demonstrated that AT is transferred from ßCD-AT-AuNPs, being available to exert its antibacterial activity. In conclusion, this novel ßCD-AT-AuNPs ternary system is a promising alternative to improve the delivery of AT drugs in therapy.

Assuntos

Ouro/química , Nanopartículas Metálicas/química , Preparações Farmacêuticas/metabolismo , Tiazóis/química , beta-Ciclodextrinas/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Transporte Biológico , Cristalização , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Permeabilidade , Pós , Espectroscopia de Prótons por Ressonância Magnética , Solubilidade , Soluções , Espectrometria por Raios X , Tiazóis/farmacologia , Difração de Raios X , beta-Ciclodextrinas/farmacologia

RESUMO

Alpha-Cyclodextrin (alpha-CD) inclusion compounds containing the carboxylic acids (octanoic, decanoic, lauric or dodecanoic, myristic or tetradecanoic, palmitic or hexadecanoic and stearic or octadecanoic) as guests were synthesized and applied for preferential adhesion of silver nanoparticles (AgNPs). The binding affinity depends of the chain length of the respective guest and is most efficient for octanoic and decanoic acids. The immobilization of nanoparticles is caused by the spatial replacing of the stabilized shell of the nanoparticles by COOH groups of the guests molecules, located at the entrance of cavity of alpha-CD, corresponding to the {001} crystal plane. Crystalline coating with nanoparticles provides a means of storing of AgNPs on solids state without aggregation. The stabilization of the particles on the surface is valid for a given length and ordering of the guest in the cavities of the alpha-CD being the octanoic and decanoic acid the most appropriated.

RESUMO

The preferred deposition of gold nanoparticles (Au NPs) onto microcrystal faces of alpha-cyclodextin/octanethiol inclusion compound was obtained. The immobilization of Au NPs is caused by the spatial replacing of the citrate shell of the NPs by the free dangling SH groups of the guest molecule.