Release efficiency and UV–vis absorption spectra of IBU. (A) Release efficiency of IBU in the PBS system. The insert is the standard curve of CIBU absorbance. (B) The UV–vis absorption spectra of IBU in the different release times. Curve a, IBU hexane solution before drug loading; curve b, the SBF solution after the release of IBU-loaded SiO2 · Eu2O3 HSs for 4 h; curve c, the SBF solution after the release of IBU-loaded SiO2 · Eu2O3 HSs for 70.
Li et al. Nanoscale Research Letters 2013 8:435 doi:10.1186/1556-276X-8-435