Modification of dry-gel synthesized MIL-100(Fe) with carboxymethyl cellulose for curcumin slow-release

Bio-metal–organic framework (Bio-MOF) is a type of MOF which is promising in biomedical applications, including for slow-released hydrophobic drugs, for example, curcumin. In this research, we investigated the influence of surface modification of MIL-100(Fe) with carboxymethyl cellulose (CMC) and its profile in the slow-release of curcumin at different pH. MIL-100(Fe) was synthesized by the dry gel conversion (DGC) method. XRD and FTIR analysis confirmed that MIL-100(Fe) was successfully synthesized. Based on the nitrogen sorption isotherm measurement, MIL-100(Fe) is classified as micro-porous material. Morphological analysis using SEM and TEM showed that the MIL-100(Fe) formed aggregates with an average particle size of 7.37 ± 2.21 nm. Curcumin was successfully encapsulated into MIL-100(Fe) in ethanol: water with a volume ratio of 1: 1 for 48 h to produce cur@MIL-100(Fe) and has drug loading capacities of 19.267 mg/g, and drug loading efficiency up to 792.324 mg/g. Furthermore, cur@MIL-100(Fe) was modified ex-situ using CMC to form cur@MIL-100(Fe)@CMC. The release of curcumin from cur@MIL-100(Fe) and cur@MIL-100(Fe)@CMC was carried out in a 1% tween-phosphate-buffered saline (PBS) solution medium (at pH 5.8 and pH 7.4). The concentration of curcumin released was determined based on the absorbance observed on the UV–Vis spectrophotometer. Cumulative percent release (CPR) of curcumin from cur@MIL-100(Fe) at 48 h reached 82.21 ± 3.0% in tween-PBS media pH 5.8 and 40.10 ± 3.35% in tween-PBS media pH 7.4, and shows constant results afterward. The CPR of curcumin from cur@MIL-100(Fe)@CMC at 48 h reached 5.94 ± 0.02% in a tween-PBS solution of pH 5.8, and 7.64 ± 0.05% in a tween-PBS solution at pH 7.4. The presence of CMC is able to suppress the release of excessive curcumin from MIL-100(Fe) and this system shows a different release profile at different pH, so it has the potential to be used as a pH-responsive drug delivery system.