Functional groups influence and mechanism research of UiO-66-type metal-organic frameworks for ketoprofen delivery

UiO-66 metal-organic framework (MOF) was introduced as ketoprofen delivery system for treating osteoarthritis (OA), and two different kinds of -NH2 and -NO2 functional groups were grafted into the UiO-66 framework to investigate the effect of functional groups on the drug loading level and release rate. Structural characterization of the samples showed that grafting functional groups had no significant effect on the morphological characteristic and crystal structure of UiO-66. All synthesized MOFs carriers had excellent BET, chemical and thermal stability, though the introduction of -NH2 and -NO2 functional groups were detrimental for these characteristics. Ketoprofen was successfully loaded on the MOFs carriers, and the results of high performance liquid chromatography (HPLC) indicated UiO-66-NH2 had the highest loading amount (38%). The ketoprofen release experiment manifested that UiO-66-NH2 exhibited lowest release rate and partial release of ketoprofen (about 65%) even after 72 h due to the high hydrogen bonds capacity and alkaline characteristic of -NH2. Furthermore, chondrocyte cytotoxicity experiment manifested that the synthesized MOFs carriers were rather bio-safe, which ensured them to be used as the drug delivery vehicles.