Supramolecular hydrogels of β-cyclodextrin linked to calcium homopoly-l-guluronate for release of coumarins with trypanocidal activity

Association constants and thermodynamicsparameters on inclusion of four 3-amido coumarins that present trypanocidal activity, into 6-amino-β-cyclodextrin (1:1 stoichimetry) were determined. In addition, pure homopolymeric-α-l-guluronate fraction prepared by partial hydrolysis of sodium alginate from Sub-Antarctic Kelp Durvillaea antarctica was conjugated with 6-amino-β-cyclodextrin (64% yield). To glycoconjugates, 3-amido coumarins were incorporated (73% of encapsulation) and supramolecular hydrogels were prepared by gelation with Ca2+ ions. The trypanocidal activity of the inclusion complexes increased by 10%. Likewise, an increase in diffusion in artificial membrane was observed (13%). It was found that the inclusion complexes increased the variation of the mitochondrial potential of T. cruzi (17%). The lowest release of substituted amidocoumarins (ACS) from supramolecular hydrogels occurred at pH 1.2 whereas the maximum release (34%) was observed at pH 8.0. Encapsulation of lipophilic bioactive compounds in supramolecular hydrogels allows the generation of release systems sensitive to pH with potential application in biomedicine. •Inclusion complexes increase of passive diffusion of substituted amidocumarins in artificial membrane (PAMPA).•The trypanocidal activity of inclusion complexes increased by 10% in relation to free amidocumarins.•Inclusion complexes increased the variation of the mitochondrial membrane potential of T. cruzi in relation to free amidocumarins.•Supramolecular hydrogels allowed the controlled release by pH of amidocumarins; reaching the maximum release at pH 8.