Effect of crosslinking with Ca<sup>++</sup> and Zn<sup>++</sup> in the formation of gellan gum gels
This study involves an investigation of the effects of crosslinking of gellan gum (GG) with Ca<sup>++</sup> or Zn++ on the physical properties of GG gels. GG gels crosslinked with different concentrations of Ca<sup>++</sup> or Zn<sup>++</sup> were prepared and par...
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| Autores principales: | , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2012
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/25642 http://www.latamjpharm.org/resumenes/31/6/LAJOP_31_6_1_4.pdf |
| Aporte de: |
| Sumario: | This study involves an investigation of the effects of crosslinking of gellan gum (GG) with Ca<sup>++</sup> or Zn++ on the physical properties of GG gels. GG gels crosslinked with different concentrations of Ca<sup>++</sup> or Zn<sup>++</sup> were prepared and parameters such as % water holding capacity and penetration thickness were investigated as measures of the extent of interaction of Ca<sup>++</sup> or Zn<sup>++</sup> with GG molecules. Data generated from the above studies revealed that Zn<sup>++</sup> interacted with the GG molecules to a greater extent than Ca++ . In order to further strengthen our finding, we have prepared Zn<sup>++</sup> crosslinked and Ca<sup>++</sup> crosslinked floating GG beads respectively by ionotropic gelation in the presence of a gas-generating agent (NaHCO3 ) and compared their physico-chemical properties such as density, drug entrapment efficiency and release in 0.1 M HCl (pH 1.2) using metronidazole (MTZ) as a model drug. Experimental data suggested that Zn<sup>++</sup> crosslinked floating GG beads were denser and less buoyant than Ca<sup>++</sup> crosslinked floating beads but capable of significantly (p < 0.05) improving MTZ entrapment efficiency and sustaining the MTZ release in 0.1 M HCl (pH 1.2) compared to Ca++ crosslinked floating beads. The difference in observed behavior may be attributed to differences in specificity, soft and hard character, enthalpies of hydration and ionization potentials of Ca<sup>++</sup> and Zn<sup>++</sup> . |
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