Preparation of ternary hybridized chitosan microspheres with photothermal effect for pH-sensitive long-lasting...

To enhance the effective utilization of drugs and diminish the number of medications for patients, it is vital to investigate controlled long-acting drug release systems and their release mechanisms. In this study, chitosan microspheres were synthesized by cross-linking pH-sensitive Schiff bases, and Zif-8, a pH-sensitive component, was encapsulated within them. Furthermore, MXene was incorporated as a third component to augment the strength and photothermal synergistic characteristics of the microspheres. By adjusting the ratio of each component, the optimal ternary heterogeneous functional pH-controllable long-lasting drug release system was obtained. The optimal coating and the most effective adsorption-release effect were achieved. The release mechanism was examined under varying pH and temperature conditions. The release process was found to be divided into three stages. The initial phase was predominantly governed by the Fick diffusion mechanism, whereas the subsequent phases were primarily regulated by the pH-induced co-decomposition of CS and Zif-8, and the individual decomposition of CS, respectively. The drug was observed to be released in a linear manner during the latter two stages of the experiment. This was evidenced by the persistent release of ciprofloxacin hydrochloride in response to pH changes, and further supported by the results of tests on its antimicrobial properties. The drug release persisted for over three days at pH 5.4 and could be utilized repeatedly, exhibiting promising applications in drug delivery. Moreover, the drug's photothermal properties offer the possibility of developing synergistic therapeutic programs.