The role of water in the confinement of ibuprofen in SBA-15

Abstract

The introduction of ibuprofen into mesopores of SBA-15 has been accomplished using the melting method. Samples exhibit from 9 to 33% of the hydrophobic drug. They are not toxic to mouse monocyte-macrophage cells and do not stimulate a pro-inflammatory response. The sample with 25% of the drug showed no crystalline ibuprofen and almost filled the mesopores, while the sample with 33% showed a total filling of the mesopores with some crystalline ibuprofen present. By means of 1D (¹H, ¹³C HPDEC, ¹³C CP MAS) and 2D (¹H–¹H NOESY) MAS NMR spectroscopy, it has been shown that water coexists with ibuprofen in mesopores and has an impact on the mobility of ibuprofen molecules and their location within the sample (outside or inside mesopores). Studies in the dehydrated state show for the first time that the high mobility of ibuprofen in mesopores is directly connected to the presence of water. Dehydrated samples show slightly slower release rates in comparison to their hydrated counterparts.