Synthesis and Characterisation of Sulfated Amphiphilic a-, b- and g-cyclodextrins: Application to Complexation of Acyclovir
Alix Dubes, Ghania Degobert, Hatem Fessi, Hélène
Parrot-Lopez,
The synthesis of sulfated amphiphilic a-, b- and g-cyclodextrins was achieved according to the standard protection-deprotection procedure. The formation of inclusion complexes between the amphiphilic a-, b- and g-cyclodextrins and an antiviral molecule, acyclovir (ACV) was investigated by UV-vis spectroscopy and electrospray ionisation mass spectrometry (ESIMS). UV-vis spectroscopy allowed determination of the stoichiometry and the stability constants of complexes, whereas ESIMS, a soft ionisation technique, allowed the detection of the inclusion complexes. The results showed that the non-sulfated amphiphilic cyclodextrins exhibit a 1:2 stoichiometry with acyclovir, while sulfated amphiphilic cyclodextrins, except g-cyclodextrin, exhibit a 1:1 stoichiometry indicating the loss of one interaction site. Non-covalent interactions between acyclovir and non-sulfated amphiphilic cyclodextrins appear to take place both in the cavity of the cyclodextrin and inside the hydrophobic zone generated by alkanoyl chains. In contrast, in the case of sulfated amphiphilic cyclodextrins, the interactions appear to involve only the hydrophobic region of the alkanoyl chains.
Author Keywords:
Amphiphilic cyclodextrins; Sulfated cyclodextrins; Acyclovir;
Inclusion complexes; UV characterisation; Electrospray ionisation
mass spectrometry
