Synthesis and Kinetic Study of Ion-Doped Zif-8 Nanocarriers for a Flutamide Delivery

Here, we describe characterization of new Zif-8 composites doped with magnetite (Fe3O4) and gold (Au) nanoparticles, labeled Zif-8-Fe and Zif-8-Au, to precisely tune their release kinetics, drug loading, and porosity. Geometry modification was observed in SEM images after ion doping, with the mean size ranging from 50-80 nm for Zif-8 and Zif-8-Au and about 500 nm for Zif-8-Fe. A clear XRD peak shift confirmed the successful incorporation of dopant ions. Brunauer-Emmett-Teller (BET) analysis revealed that while Au doping significantly reduced the material’s surface area and pore volume, Fe doping remarkably enhanced these properties (556 vs 2676 m2/g and 0.26 vs 1 cm3/g, respectively). This directly impacted drug loading, with the Zif-8-Fe composite demonstrating the highest loading capacity (18.8 mg/g) and Zif-8-Au showing the lowest (7.2 mg/g). In vitro drug release studies further demonstrated distinct kinetic profiles. The release from all samples followed a Fickian diffusion mechanism, as indicated by the Korsmeyer-Peppas model (n ≈ 0.01 − 0.05). The Zif-8-Fe composite exhibited a desirable sustained-release profile due to its enhanced and more tortuous pore network, while the Zif-8-Au composite showed low-quantity release. The findings demonstrated that ion doping provided a powerful strategy to engineer the structural properties and drug release kinetics of MOFs.