Efeito da modificação química na solubilidade e intumescimento de microesferas à base de goma do cajueiro carboximetilada e quitosana

Abstract

ResumoEsferas de goma do cajueiro carboximetilada e quitosana foram produzidas via complexação polieletrolítica. As esferas foram modificadas quimicamente de modo a obter-se sistemas estáveis em meio ácido e que apresentassem uma resposta de intumescimento diferenciado frente à variação de pH. As esferas foram modificadas por reacetilação da quitosana e por reticulação com epicloridrina, glutaraldeído e genipina. As esferas reticuladas foram caracterizadas por meio de técnicas como: espectroscopia de absorção no infravermelho, análise termogravimétrica, microscopia eletrônica de varredura e quanto à solubilidade em pH 1,2 e ao intumescimento. As esferas de goma do cajueiro carboximetilada e quitosana reacetilada, e as esferas reticuladas com epicloridrina apresentaram baixa resistência à dissolução em pH 1,2. Entretanto, as esferas reticuladas com glutaraldeído e genipina apresentaram resistência à dissolução e baixo coeficiente de difusão. As esferas reticuladas com genipina apresentaram um grau de intumescimento maior do que as esferas reticuladas com glutaraldeído nas concentrações de 3% e 5% (massa/volume). As esferas reticuladas com genipina apresentaram intumescimento responsivo à variação de pH e estabilidade em pH 1,2, indicando que esses sistemas possuem potencial para uso em sistemas de liberação controlada de fármacos por via oral. PalavrasTchave: goma do cajueiro, carboximetilação, quitosana, reticulação. AbstractChitosan/carboxymethylated cashew gum beads were produced via polyelectrolytic complexation. The beads were chemically modified to achieve stable acidic medium and to provide a swelling response in different pH. The beads were modified by chitosan reacetylation and by crosslinking with epichlorohydrin, glutaraldehyde and genipin. The beads were characterized by techniques such as: infrared spectroscopy, thermogravimetry, scanning electron microscopy and regarding their solubility at pH 1.2 and swelling. The beads of carboxymethyl cashew gum and reacetylated chitosan and those crosslinked with epichlorohydrin had low resistances to dissolution at pH 1.2. However, the beads crosslinked with glutaraldehyde and genipin showed resistance to dissolution along with low diffusion coefficients. Moreover, beads crosslinked with genipin presented a higher degree of swelling than beads crosslinked with glutaraldehyde at concentrations of 3% and 5% (weight/volume). Beads crosslinked with genipin presented responsive behavior to pH variation and stability at pH 1.2, indicating that these systems have potential for use in controlled drug delivery systems for oral administration.

Seafood Waste as Attractive Source of Chitin and Chitosan Production and Their Applications

“…Chitosan has the characteristic of solubility in acidic media because of the free amino groups being protonated (NH3 +), where the precipitation tendency increases from the moment the pH approaches 6.0, regarding the increase of -NH2 clusters in the molecular structure. Thus, amino groups make it possible for them to bind to negatively charged materials, such as other polysaccharides, enzymes, and cells, being insoluble in water, concentrated acids, acetone, and alcohol [76][77][78].…”

Acerola by-product as a renewable source of bioactive compounds: arabic gum and maltodextrin nanocapsules

“…The control sample also shows the same absorption profile with the characteristic bands, but with little intensity. Monteiro et al (2015) also found similarity between the FTIR spectra of their polyelectrolyte complexes in the formation of microspheres and the spectra of their wall materials. 2018prepared an apple pomace polyphenolic extract loaded into biodegradable and commercially available natural polymer such as maltodextrin and identified the functional groups of the active components and also any interaction modes between the polymeric wall and the polyphenolic core by FTIR.…”

Innovation of advanced polymers from seafood waste: Applications of chitin and chitosan

“…Thus, amino groups enable them to attach with negatively charged particles, which include other polysaccharides, enzymes, as well as cells, while remaining impermeable in water, highly concentrated acids, acetone, and ethanol. [169][170][171] Several studies on chitosan have been conducted in the past few years, demonstrating a solid link among both the structural as well as morphological aspects of chitin, chitosan, and related compounds, as well as their qualities and possible uses. 172 This kind of polymer is commonly present in tiny amounts in the cell walls of certain fungi (Zygomycetes), or it may be produced by acidic hydrolysis of chitin from crustaceans as well as arthropod exoskeletons.…”

“…Chitosan is readily soluble in acidic solutions due to the protonation of free amino groups (NH 3 + ), and its precipitating tendency rises when the pH exceeds 6.0, indicating a rise in NH 2 complexes in the structure of the molecules. Thus, amino groups enable them to attach with negatively charged particles, which include other polysaccharides, enzymes, as well as cells, while remaining impermeable in water, highly concentrated acids, acetone, and ethanol 169–171 . Several studies on chitosan have been conducted in the past few years, demonstrating a solid link among both the structural as well as morphological aspects of chitin, chitosan, and related compounds, as well as their qualities and possible uses 172 .…”