Synthesis, characterization of biocompatibility and evaluation of bioadhesion of n-carboxymethylchitosan nanoparticles in hybrid networks with poliacrylic acid / Síntese, caracterização e avaliação da biocompatibilidade e bioadesão de nanopartículas de n-carboximetilquitosana em redes híbridas com ácido poliacrílico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Chitosan nanoparticle complexes with polyacrylic acid have been used in nanotechnology, as they improve pharmacological activity, in chemical and biological terms, and in particular, increase drug bioavailability. The aim of this work is to evaluate the biocompatibility and bioadhesion of N-carboxymethyl derivatives of chitosan (N-CMC) with in situ polymerization with acrylic acid, generating hybrid networks with polyacrylic acid. The chitosan samples were derivatized by N-carboxymethylation with glyoxilic acid and subsequent formation of hybrid networks by polymerization with acrylic acid (N-CMCA). Cross-links were also carried out with N,N-methylene-bisacrylamide (N-CMCR). The N-CMC samples were characterized in relation to degree of deacetylation and carboxymethylation, and the chemical structure of all the derivatives was confirmed by infrared spectroscopy (IR) and nuclear magnetic resonance (13C NMR). The loss of mass of the derivatives was evaluated by thermogravimetry (TG) and differential scanning calorimetry (DSC). The hydrodynamic radius (Rh) of nanoparticles obtained by spray drying was analyzed by dynamic light scattering, and the size and morphology by scanning electronic microscopy (SEM). The bioadhesion of the systems was analyzed after oral administration of the fluorescent nanoparticles N-CMCA-FITC and NCMCR- FITC in rats, with analysis of the adhered particles in the stomach and initial, medium and final portions of the small intestine, after 1 h, 5,5 h and 8 h. The degree of chitosan deacetylation was 85%. The N-carboxymethylation of chitosan was confirmed by IR with characteristic bands at 1650 and 1550 cm-1. After ethanol precipitation and drying, the NCMC derivative showed a degree of carboxymethylation of 60% by titration. The Rh of N-CMC was 76.2 nm. The synthesis of derivatives N-CMCA and N-CMCR was confirmed by the increase of IR bands at 1650 cm-1, as well as by the characteristic chemical shift of acrylation by 13C NMR. The morphology by SEM of the nanoparticles obtained by spray drying showed a spherical structure. The N-CMCA and N-CMCR derivatives showed an increase in thermal stability, with a reduction in loss of mass, compared with the N-CMC. In the biocompatibility studies, the N-CMC, N-CMCA and N-CMCR derivatives did not present any cytotoxic effects, even at a high concentration of 1000 μg/mL, and the N-CMCR nanoparticles showed the highest bioadhesion capacity, with a total residence time of 4.0 h in the stomach and small intestine. The nanoparticles obtained have potential to deliver drugs in the stomach, for example in ulceration and inflammation related pathologies

ASSUNTO(S)

nanoparticles bioadhesion nanopartículas copolimerização farmacia acrylation n-carboximetilquitosana bioadesão acrilação n-carboxymethylchitosan copolymerization

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