Yong Jae Suh

pH-sensitive mesalazine carrier for colon-targeted drug delivery: A two-fold composition of mesalazine with a clay and alginate

AbstractThe release of mesalazine, an anti-inflammatory drug for Crohn’s disease, should be deferred while delivering along the gastrointestinal tract to maximize drug absorption in the colon. To that end, we intercalated mesalazine into a clay mineral, montmorillonite (MMT), and we encapsulated the resulting composite inside a pHsensitive polymer, an alginate hydrogel bead. Once intercalated between the microscopic MMT layers, the mesalazine is prevented from dissolution during encapsulation into the alginate beads. As the resulting mesalazine-clay-alginate (MCA) bead is covered with a protective alginate layer, the mesalazine does not dissolve in acidic gastric conditions. In in vitro release tests, the MCA beads exhibited less than 5% mesalazine release in gastric solution, while ~20% was released over 7 h in the intestinal condition. Our results demonstrate that the MCA bead is a highly effective, biocompatible means of mesalazine delivery to the colon.

Use of low-grade iron ore for producing a nano-adsorbent and a complex fertilizer

We developed a technology that prepares magnetite nanoparticles (MNPs) from a low-grade iron ore and consumes the by-product wastewater in removing phosphorus and nitrogen in water. The silica that inhibits the MNP formation and that is present in the iron ore leachate was removed by co-precipitation with Al(OH)3. From the supernatant, ferric hydroxide was allowed to be precipitated, leaving Mg2+ behind. The precipitated hydroxide was used as a starting material in preparing the MNPs of 5–15 nm in size by co-precipitation. The wastewater containing a large amount of Mg2+ generated from the ferric hydroxide precipitation stage was used to crystallize and ions in the form of struvite. This process enables the reduction of the cost of Mg2+ in water treatment and the cost of iron ore wastewater treatment. The valuable elements contained in the iron ore can be exploited to produce MNPs and struvite powder as a nano-adsorbent and a composite fertilizer, respectively. Our results suggest that low-grade iron ore or tailings can be applied to alleviate water and soil contamination.