Abstract
Immobilization of antimicrobial drug is one of the fascinating approach to expand the application of antibacterial property to consumer product. In order to stabilize antimicrobial agent, levofloxacin (LVX), into polymer substrate for sustained antibacterial activity, the drug molecules were immobilized in layered double hydroxide (LDH) and embedded in polyurethane substrate. As prepared MgAl-LDH was calcined at 400C and reconstructed with LVX for intercalation. The X-ray diffraction patterns and cross-sectional transmission electron microscopy images showed lattice expansion along the crystallographic c-axis upon LVX intercalation, suggesting the successful loading of the drug. Fourier-transformed infrared spectra revealed that intact structure of LVX was well preserved between LDH layers. Elemental analysis indicated that the loading capacity of LVX in the hybrid was 41.7%. Bacterial colony forming inhibitory assay of exhibited ~100% antibacterial activity for both LVX alone and LVX-LDH hybrid (LL) on Bacillus subtilis. To determine sustainability of antibacterial activity by the hybrid, either LVX alone or LL hybrid was loaded in polyurethane (PU) substrate of which antibacterial activity was evaluated before and after immersing in phosphate buffered saline for 3 days. The LVX composited PU showed dramatic decrease in antibacterial activity down to 0% after buffer treatment; however, LL composited PU still contained antibacterial activity (~34% of colony suppression) after phosphate buffered saline immersion.