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Enhanced solubility and antibacterial activity of lipophilic fluoro-substituted N-benzoyl-2-aminobenzothiazoles by complexation with β-cyclodextrins

https://doi.org/10.1016/j.ijpharm.2015.11.024Get rights and content

Abstract

Some lipophilic fluoro-substituted N-benzoyl-2-aminobenzothiazole antibacterial agents have been evaluated for their activity in the presence of cyclodextrins (CDs) containing aqueous solutions where CDs are adopted as solubilizing excipients for improving the poor water solubility of these compounds. For such purpose both the natural β-CD and one of FDA/EMA approved CDs for parenteral use (i.e. HP-β-CD) have been employed. The solubility rank order observed was accounted for by thermal analysis (Differential Scanning Calorimetry) and FT–IR spectroscopy. The most promising compound was subjected to further NMR spectroscopic studies and molecular modelling simulations to verify the interactions between the guest molecule and the CD cavity. The assessment of the antibacterial activity of such compounds against selected Gram positive and Gram negative bacterial strains clearly showed that their antimicrobial effectiveness may, quite in all instances, be positively affected by complexation with β-CD and HP-β-CD. These results, which are in some ways in contrast with those already reported in the literature, are herein discussed on the basis of plausible mechanisms. Moreover, this investigation also reveals that the described methodology of complexing both lipophilic and hydrophilic antimicrobial agents with CDs may be an useful approach to enhance their effectiveness as well as a promising strategy to overcome even the microbial resistance problem.

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Cited by (5)

  • Effect of Methyl-β-Cyclodextrin on the antimicrobial activity of a new series of poorly water-soluble benzothiazoles

    2019, Carbohydrate Polymers
    Citation Excerpt :

    Such literature suggestion is confirmed by our findings in the case of the S-unsubstituted benzothiazole compound 2 but not with 1. An important objective of this work was to gain information on the possible mechanism(s) of antibacterial activity enhancement after complexation with CDs and, in this regard, several proposals have been made (Athanassiou et al., 2003; Trapani et al., 2016) which essentially focus on two aspects. The first one is the improvement of dissolution properties arising from the complexation with CDs.

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