Adsorption behavior of pazufloxacin mesilate on amino-functionalized carbon nanotubes.

In this study, the interaction between amino-functionalized multi-walled carbon nanotubes (e-MWNTs) and antibacterial agents was investigated and the drug-loading ability of e-MWNTs was evaluated. The e-MWNTs were prepared and characterized, then were used as adsorbents for loading an antibacterial agent, pazufloxacin mesilate (PZFX). The adsorption behavior of PZFX on e-MWNTs in water was investigated. The results showed that e-MWNTs were able to form supramolecular complexes with PZFX and could be used as drug carriers with high drug-loading efficiency. Compared with pristine multi-walled carbon nanotubes (MWNTs), the adsorption efficiency of e-MWNTs was better. In kinetic studies, the pseudo-second-order model showed satisfactory fitting and good adsorption process. Langmuir model was successfully employed to describe the adsorption isotherms of PZFX on e-MWNTs and higher drug-loading ability were observed from e-MWNTs with smaller diameter. The adsorption process of e-MWNTs was sensitive to the pH and it was observed that the neutral pH gave the best adsorption. Low temperatures facilitated the adsorption process. In addition, the release process of PZFX from e-MWNTs occurred in two stages: a rapid release, then followed by a slow release, in which acidic solution favored the release process. In summary, our technique developed for the adsorption of PZFX on e-MWNTs is satisfactory.