Synthesis and Functionalization of Porous Zr-Diaminostilbenedicarboxylate Metal-Organic Framework for Storage and Stable Delivery of Ibuprofen

A stable porous metal-organic framework (MOF), Zr-diaminostilbenedicarboxylate (Zr-DASDCA), was synthesized and modified with oxalyl chloride (OC) or terephthaloyl chloride (TC) to introduce various functional groups onto the Zr-DASDCA. Both pristine and functionalized Zr-DASDCAs, together with activated carbon, were used as a potential carrier for ibuprofen (IBU) storage and delivery. Zr-DASDCAs, especially the modified ones (OC-Zr-DASDCA and TC-Zr-DASDCA), showed competitive results in IBU delivery. Specifically, the release rate in phosphate-buffered saline solution at pH 7.4 was nearly constant (R² ≈ 0.98) for up to 10 days, which would be very effective in IBU dosing to the human body. Moreover, the release rate could be controlled by changing the pH of the releasing solution. The rate of IBU release from both pristine and modified Zr-DASDCAs at pH 7.4 and 3.0 was also explained with a few interactions such as H-bonding and electrostatic repulsion, together with the relative pore size of the Zr-DASDCAs. Therefore, the results suggested that functionalization of MOFs via postsynthetic modification, especially with OC and TC, to introduce various functional groups onto MOFs is an effective approach to not only reducing the release rate of IBU but also inducing a constant release of IBU for as long as 10 days.