De novo synthesis and particle size control of iron metal organic framework for diclofenac drug delivery

Metal organic frameworks (MOFs) possess lots of potential but what limits its applicability in the industrial setting is the sustainability of its preparation. This work features room temperature synthesis of MIL-100(Fe) without using toxic organic solvents and strong acids. Using varying ratio of trimesic acid (BTC) to diclofenac (DCF) as ligand during synthesis, DCF was directly incorporated within the MIL-100(Fe) framework. The products synthesized showed similar PXRD patterns with the calculated value for MIL-100(Fe). The de novo synthesized products (D1-D5) were compared to conventional DCF loading in MIL-100(Fe) (DCF@MIL) wherein they show comparable characteristics. SEM images also confirmed that the octahedral morphology of MIL-100(Fe) was preserved even when DCF substituted some BTC as ligand. DCF release in simulated body fluids were determined and showed sustained release over a 24-h period at pH 7.4. On the other hand, negligible release was observed at pH 1.2 which is favorable as DCF can be protected from enzymatic degradation in the stomach, thus more DCF can be delivered to the systemic circulation. Among the synthesized bio-MOFs, D2 showed promising results with 20% loading capacity and 94% entrapment efficiency. Controlled particle size (100–400 nm) with varied reaction time was achieved with DCF acting as modulator. Results showed that longer reaction time yielded larger particle size, higher porosity, and enhanced drug release. This study demonstrates the versatility of DCF wherein aside from being the active drug, it may also act as modulator in MOF synthesis for particle size control.