ZIF-8 derived spherical porous carbon as an efficient sustained-release carrier for nitroimidazole drugs

Conventional porous carbon (PC) as a drug carrier still remains some drawbacks such as irregular shapes, low drug loading capacity, uncontrollable release time, etc. In this contribution, a novel spherical porous carbon (SPC) was prepared by direct carbonization of ZIF-8 precursor wrapped with resorcinol-formaldehyde (RF) resin. The morphology evolution of the ZIF-8 derived SPC (ZSPC) has been discussed, which are subject to the dosage of ZIF-8. By simulating the human body's internal environment at different pH values, the carrying and releasing capacity of ZSPC toward metronidazole (MNZ) and ornidazole (ONZ) were systematically evaluated, and the testing data was accordingly fitted by adsorption isotherms, adsorption kinetics, and drug release kinetics models. The maximum drug loading and release time of ZSPC toward MNZ and ONZ reached (300 and 280 mg/g) and 24 h, which were superior to the previous reports. Furthermore, the ZSPC also have a large surface area and low cytotoxicity towards 293T and Hela cells within the range of 10–1000 μg/mL tested. Anyway, this work could confirm ZSPC has great potential as a carrier for nitroimidazole drugs.