The effect of polyelectrolyte counterion specificity, charge density, and conformation on polyelectrolyte–amphiphile interaction: The carrageenan/furcellaran–amitriptyline system
✍ Scribed by Andreas Hugerth; Lars-Olof Sundelöf
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2000
- Tongue
- English
- Weight
- 133 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
The effect of polyelectrolyte cation specificity, charge density, and conformation on the interaction between furcelleran, , , and -carrageenan, respectively, and amitriptyline, an amphiphilic cationic drug molecule, was studied by means of a dialysis equilibrium technique. The carrageenans used in this study-furcelleran, , , and -carrageenanhad a charge density corresponding to 0.69, 0.92, 1.53, and 2.07 sulfate groups per disaccharide. In general, the binding isotherms followed the order Li ϩ Ͻ Na ϩ Ͻ N(CH3) 4 ϩ Ͻ K ϩ Յ Cs ϩ Ϸ Rb ϩ , i.e., the binding isotherms were shifted to higher concentrations of free amphiphile according to the sequence indicated. This affinity sequence correlates well with that found for the dextran sulfate-amitriptyline system (A. Hugerth and L.-O. Sundelo ¨f, Langmuir 2000, 16, 313-317). The factor determining the critical aggregation concentration in the presence of Na ϩ compared to K ϩ was found to be as follows: the flexibility (conformation) in the case of the lower charged carrageenans, i.e., furcelleran and -carrageenan, charge density for -carrageenan, and in the -carrageenan case the difference in the ROSO 3 Ϫ -alkali ion specificity.