Síntese, caracterização físico-química e avaliação da atividade antibacteriana e do potencial antitumoral dos complexos de inclusão de ofloxacino com ciclodextrinas

Abstract

The ofloxacin (OFLOX) is a second-generation antibiotic of the fluoroquinolone class with a broad spectrum of action against Gram-negative and Gram-positive bacteria, killing them by the inhibition of DNA gyrase and topoisomerase IV. In addition to its bactericidal activity diverse fluoroquinolones, and their synthetic derivatives, shown a cytotoxic effect in different tumor cell lines, being as promising agents for the treatment of cancer. In the attempt to develop, or even improve the characteristics of existing drugs, the inclusion of poorly water soluble drugs in cyclodextrins has been highlighted due to the improvement in solubility, stability and bioavailability. Therefore, the objective of this work was to synthesize, characterize and evaluate the improvement of the anti-bacterial and antitumor activity of OFLOX after inclusion in βCD and HPβCD. The physico-chemical characterization was performed by infrared spectroscopy, nuclear magnetic resonance of 1H (NMR of 1H), thermal analysis, isothermal calorimetric titration (ITC) and dynamic light scattering. The minimum inhibitory concentration (MIC), death curve evaluation, MTT cytotoxicity assay and apoptosis by flow cytometry of inclusion complexes (IC’s) were performed for the biological assays. Through the results of infrared, thermal analysis and NMR of 1H it was possible to verify the occurrence of inclusion of OFLOX in both cyclodextrins. The thermodynamic data obtained by ITC showed the formation of IC’s with 1:1 stoichiometry, being the spontaneous processes and with different values for the association constants. Through the DLS the size of the ICs was evaluated, and these presented a smaller size when compared to OFLOX. In relation to the in vitro biological tests, the MIC of the IC’s was lower for the tested bacterial strains, but the death profile remained the same as to pure OFLOX. In the cytotoxicity assay, it was possible to observe that the IC’s were able to reduce the viability of A549 cells, presenting better results when compared to OFLOX. The death caused in these cells was mostly by apoptosis. The results showed better antimicrobial and anticancer activities of the IC’s. Further studies are necessary to prove the use of these IC’s as candidates to treating these pathologies.