Extract of curcuminoids loaded on polycaprolactone and pluronic nanoparticles: chemical and structural properties

The purpose of this work was to obtain and characterize curcuminoids loaded nanoparticles based on polycaprolactone and poloxamer whose pharmaceutical applicability justifies its relevance since polyphenolic compounds carriers have anti-inflammatory, antioxidant, antitumor and anti-amyloid potential. The curcuminoids' extracts (CUR) were obtained from Turmeric (Curcuma longa Linn.) using acetone as organic solvent. Its chemical characterization was done by Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and chiefly by nuclear magnetic resonance (NMR). The polymeric nanoparticles (NPs) were prepared by nanoprecipitation, maintaining all reaction parameters, except for the amount of CUR incorporated in the polycaprolactone (PCL) matrix, which was, respectively, 0%, 5%, 10%, 15% and 20% (percentage in relation to PCL mass) in samples here called 0, 5, 10, 15 and 20. The obtained NPs were analyzed in suspension for size study (by dynamic light scattering-DLS), zeta potential (ZP) and color change, and in powder form, after freeze-drying, for structural study of molecular mobility (by TD-NMR), Scanning electron microscopy (SEM), encapsulation efficiency, and elucidation of composition and incorporation of the extract (by NMR and FTIR). It was possible to obtain very stable spherical CUR-NPs, of size within the nanometric scale, even after 3 months of storage. The desirable surface charge and size for biomedical applications were not effectively hampered by lyophilization as well. After nanoprecipitation there was no degradation of the CUR or chemical interaction with the polymers, which is fundamental for the maintenance, enhancement and viability of its properties. Evaluating the structural NPs' properties, cost-benefit and possible system saturation, samples 15 and 20 demonstrated excess CUR. The methods used for both extraction and encapsulation proved to be efficient, reproducible, practical and inexpensive, which is very advantageous for a potential scaling and use of CUR-NPs in the pharmaceutical industry.