Red Fluorescence of Eu3+-Doped ZnAl-LDH Response to Intercalation and Release of Ibuprofen.

A drug delivery system with identification function is attractive and important. For this reason, the red fluorescence of Eu3+-doped ZnAl-LDH response to intercalation and release of ibuprofen (IBU) has been studied. X-ray diffraction(XRD) results showed that the basal spacing of the Eu3+-doped ZnAl-LDH varied from 8.85 to 12.04 Å after the intercalation of IBU. The release of the IBU from the Eu3+-doped ZnAl-LDH was carried out in simulated intestinal medium (phosphate buffer solutions with pH 7.4 and 37 °C), and the releasing behavior of IBU exhibited an initial rapid release followed by a slow release. Moreover, the present delivery system has slower release of drug than those of other LDH-based delivery systems. Interestingly, the intercalation of IBU into the Eu3+-doped ZnAl-LDH obviously reduced the red fluorescence of the Eu3+-doped ZnAl-LDH, whereas the red fluorescence was recovered after the release of IBU. This fluorescent responsiveness may be a favorable signal for detecting the delivery and release of IBU. Therefore, the Eu3+-doped ZnAl-LDH with red fluorescence would be potential application as drug delivery system with identification function because of its cheapness, non-toxicity, good biocompatibility, and little damage to biological tissue.