Inclusion Complexation of Carbethopendecinium Bromide with Some α- and β-Cyclodextrins Studied by Potentiometry with Membrane Electrodes
| Autor: | Mária Vojteková, Monika Juríčeková, František Kopecký, Silvia Kováčová |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Collection of Czechoslovak Chemical Communications. 69:384-396 |
| ISSN: | 1212-6950 0010-0765 |
| DOI: | 10.1135/cccc20040384 |
| Popis: | Inclusion complexation of an antimicrobial quaternary ammonium salt, carbethopendecinium bromide (SBr, Septonex), with five cyclodextrins was investigated potentiometrically using the prepared membrane electrodes selective to the surface-active carbethopendecinium cations (S+). Relatively strong complexation of the S+ cations with native α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and their random-substituted derivatives, namely hydroxypropyl-α-cyclodextrin (HP-α-CD), methyl-β-cyclodextrin (M-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD), was evidenced in dilute aqueous solution. In the region where the potentiometrically determined concentration of the free S+ cations remained lower than the critical micelle concentration (cmc) of SBr by a factor of ca ten, formation of the 1:1 complexes with the complexation constants K11 ≈ 104-105 was evaluated by two respective methods, based on a modified linear and a non-linear regression. Deviations from the 1:1 complexation were observed when concentration of the free S+ cations approached cmc of SBr more closely and also in solutions with large excess of α-CD. Comparison of K11 values corroborated the inclusion of the n-C14H29 alkyl chain of the carbethopendecinium cation as the mechanism of its complexation with cyclodextrins. The well-soluble native α-CD with good complex-forming capability towards S+ cations may be especially suitable for possible blocking the undesirable residues of carbethopendecinium bromide. |
| Databáze: | OpenAIRE |
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