Boosting the Sustained Release Performance of Metronidazole and Ornidazole with MIL-53(Fe) Derived Spherical Porous Carbon

Metal-organic framework (MOF) derived spherical porous carbon (SPC) has potential application value in the field of adsorption and sustained release of nitroimidazole drugs. This work used MIL-53(Fe) as a precursor and prepared spherical 3-aminophenol-formaldehyde resin containing MIL-53(Fe) crystals using the advanced Stöber method, followed by the successful preparation of MIL-53(Fe) derived SPC (MSPC) with a structure containing both micropores and mesopores through high-temperature carbonization. The effects of the doping amount of MIL-53(Fe) on the sphericity and particle size of MSPC were investigated. The drug uptake capacity and sustained release performances of MSPC for metronidazole (MNZ) and ornidazole (ONZ) were assessed through batch tests, along with an investigation into the impact of varying pH levels on the sustained release performances. The experimental findings revealed that the drug loading of MNZ and ONZ onto MSPC achieved 111 and 120 mg/g, respectively, with a sustained release time of up to 24 h. The drug loading process adhered to the Langmuir isotherm adsorption model and conformed to the pseudo-second-order kinetics model, whereas the sustained release mechanism was consistent with the Korsmeyer-Peppas model. Furthermore, cytotoxicity and cyclic drug loading experiments indicated that MSPC exhibited good biocompatibility and stability. Therefore, this study provides new ideas for the development of SPC drug carriers.