PREPARAÇÃO E CARACTERIZAÇÃO DE NANOCOMPÓSITOS À BASE DE ARGILA E GOMA DO CAJUEIRO PARA APLICAÇÃO EM SISTEMAS DE LIBERAÇÃO DE FÁRMACOS

Abstract

Nanotechnology is related to the development of materials of nanometric dimensions and currently its concept is applied in several areas of research. The development of nanomaterials has driven research, mainly with the aim of obtaining nanocomposites, due to the possibility of expanding the applications of some materials. Nanocomposites of organic and inorganic nature have been gaining prominence in applications ranging from the automotive industry to the pharmaceutical industry. This work began with a review, with the objective of obtaining bibliographic (articles) and technological (patents) information regarding nanocomposites of clays and gums. To do this, we searched the Web of Science, Scopus and Sciencedirect databases and patents in the European Patent office (EPO), World Intellectual Property Organization (WIPO), United States Patent and Trademark Office (USPTO) and Of the National Institute of Industrial Property (INPI) using descriptors related to the theme. With the results of this study it was possible to observe that guar, gellan, brea, sodium alginate, xanthan and cashew gum were already applied in the synthesis of nanocomposites with clays, and the largest number of articles published in relation to this application is With alginate. It was possible to verify that the manipulation of cashew gum and kaolinite to obtain nanocomposites is innovative until the present moment, since no patents or scientific articles were found in the databases. In this context, nanocomposite based on clay and cashew gum was synthesized and characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA) And Thermogravimetric Analysis (TGA). The material was applied in the incorporation and release of doxazosin. The influence of solution pH, adsorbent dose, initial drug concentration, contact time and temperature were evaluated. The equilibrium was reached in a relatively short time of 60 minutes, where a maximum adsorption capacity of 30.4 ± 1.63 mg g -1 was observed. To describe the mechanism controlling the adsorption process, adsorption kinetics were studied by adjusting the experimental data to kinetic models of pseudo-first-order, pseudo-second -order and intra-particle diffusion. The pseudo-second-order model presented a better description of the adsorption of doxazosin in the nanocomposite. The experimental data were also fitted to the Freundlich and Langmuir isotherms models and a good adjustment of the data was observed to the Freundlich model. The nanocomposite obtained proved to be efficient in the incorporation of doxazosin with the advantage of being synthesized from abundant raw material and relatively low cost. Preliminary results of the in vitro release indicate that the NCG nanocomposite is very promising to be used in the release of doxazosin and other similar drugs because it has a good interaction between drug and nanocomposite and a low release for pH 1.2 and high percent release to pH 7.4.