Preparação e caracterização de bases de Schiff e complexos metálicos a partir de quitosana e derivados de salicilaldeído

Araújo, Eliene Leandro de

doi:10.11606/t.75.2015.tde-29062015-154801

Cited by 1 publication

(3 citation statements)

References 81 publications

(121 reference statements)

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“…[25] Os grupos amina e hidroxila presentes em sua estrutura possibilitam reações de modificação características, tais como N-aquilação, N-acilação, intercruzamentos de cadeias, formação de sais, bases de Schiff, dentre outras. [21,27] [21,27,63] Na literatura são encontrados vários métodos que permitem a caracterização das propriedades físico-químicas da quitosana. O grau de acetilação pode ser determinado por métodos espectroscópicos como ressonância magnética nuclear de hidrogênio e carbono, RMN 1 H e 13 C; por espectroscopia vibracional na região do infravermelho, FTIR; por espectroscopia na região do ultravioleta-visível, UV-vis; além de outras técnicas como titulação potenciométrica, por calorimetria exploratória diferencial [92] e análise elementar.…”

Section: Tabelaunclassified

“…Peres em 2014 [26] estudou a dissociação de ibuprofeno utilizando matrizes de quitosana e argila montmorilonita, enquanto Luppi [62] em 2009 desenvolveu o trabalho de preparação, caracterização e estudos de liberação controlada de captopril em uma matriz de quitosana, dentre outros, que envolveram o biopolímero quitosana. [18,63] Desse modo, o presente trabalho visa a preparação de sais de quitosana e naproxeno variando os parâmetros de síntese, tais como tempo de reação, temperatura e razão molar. Os produtos obtidos foram caracterizados por espectroscopia de ressonância magnética nuclear de carbono (RMN de 13…”

Section: I4 Interação Entre Matriz Biopolimérica Com Naproxenounclassified

“…Na região de 1159-891 cm -1 verificam-se as bandas de deformações axiais de álcoois dos grupos COH (secundários, com alicíclico de 5 e 6 átomos de carbono) e C-O-C em 1159 cm -1 referente as ligações glicosídicas β(14), além da banda em 891 cm -1 de C-H da estrutura do polissacarídeo. [21,63,[75][76][77][78] Já o espectro em vermelho NAP, Figura 17, apresenta bandas características do naproxeno. Em 3196 cm -1 observa-se a banda referente estiramento O-H, em 2976 cm -1 verifica-se a banda referente ao estiramento C-H da região aromática.…”

Section: Iii2 Purificação Da Quitosanaunclassified

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Preparação, caracterização e estudo de dissociação do naproxeno em uma matriz de quitosana

Medeiros¹

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Studies were carried out to optimize the reaction conditions to obtain a naproxen (NAP) salt (QN) and the chitosan biopolymer (QP). This salt (QN) was used for the study of antiinflammatory dissociation equilibrium. For this, the best conditions were studied in relation to the parameters reaction time, reaction temperature and molar ratio of the reactants. The products were characterized by nuclear magnetic resonance NMR of hydrogen 1 H and carbon 13 C, Fourier transform infrared vibration spectroscopy, FTIR, ultraviolet-visible electronic spectroscopy in the diffuse reflectance, UV-vis, diffraction (XRD) and thermoanalytical techniques: thermogravimetry and differential thermal analysis simultaneous (TG/DTA) and differential scanning calorimetry (DSC). In addition, the evolution of gases by thermogravimetry coupled to spectrometer FTIR (TG-FTIR) was studied. It was found that the higher salt yield was obtained under the following reaction conditions: 24 hours, temperature of 60 ° C and molar ratio of 1 mol of QP to 1.05 mol of NAP. This reaction product was called QN1. In this case, when calculating the degree of substitution (GS) by the 13 C NMR technique, a GS of 19.1% was observed, suggesting a neutralization of the NH2 group bound to the C2 of the biopolymer with the COOH group present in the drug. In the FTIR spectra were observed bands corresponding to the formation of a product different than QP and NAP, corroborating with the hypothesis of QN1 salt formation. In the UV-vis spectrum the three bands were observed for the absorption of the chromophore groups present in the salt. In the diffractograms, there was a peak in the region of ~22θ in QN1, which was already observed as a shoulder in QP, but there was an increase, in addition, changes in the index of crystallinity of chitosan, suggested modifications in its semicrystalline structure after reaction with the NAP. The TG / DTG / DTA curves showed changes in the thermal behavior of QN1 in relation to QP, showing that the modification leads to changes in the thermal behavior and suggest the presence of NAP in the biopolymer matrix. The characterization confirmed the hypothesis of salt formation, QN1, because there were modifications in the intervals of mass loss, as well as, by the ratio between the third and second loss of mass, a stability gain can be verified. In order to improve the NAP-QP interaction capacity, the chitosan chains were crosslinked with epichlorohydrin. However, the reaction had a lower yield when compared to the uncrosslinked salt. It was verified by the different characterization techniques, mainly by 13 C NMR that, instead of organizing and leaving the amino groups even more susceptible to reaction, the chitosan structure was organized in a way that there was less interaction with the drug. Therefore, for the salts QN1 and QPEPIN1 the study of the equilibrium of dissociation by HPLC, at pH 2,00 and 7,00, was carried out, simulating conditions of the intestine and stomach, in order to verify their profile of dissociation and behavior...

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Section: Tabelaunclassified

Section: I4 Interação Entre Matriz Biopolimérica Com Naproxenounclassified

Section: Iii2 Purificação Da Quitosanaunclassified

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Preparação, caracterização e estudo de dissociação do naproxeno em uma matriz de quitosana

Medeiros¹

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Preparação e caracterização de bases de Schiff e complexos metálicos a partir de quitosana e derivados de salicilaldeído

Cited by 1 publication

References 81 publications

Preparação, caracterização e estudo de dissociação do naproxeno em uma matriz de quitosana

Preparação, caracterização e estudo de dissociação do naproxeno em uma matriz de quitosana

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