Storage and release of ibuprofen drug molecules in hollow mesoporous silica spheres with modified pore surface

Hollow mesoporous silica spheres with cubic pore network (HMSC) with and without modification using 3-aminopropyltriethoxysilane (N-TES), 3-(2-aminoethylamino)propyltrimethoxysilane (NN-TES) and (3- trimethoxysilylpropyl)diethylenetriamine (NNN-TES) have been successfully synthesized by a simple one-step method and post-modification. The structures, ibuprofen (IBU) drug storage capacities and release rates were characterized and investigated with various techniques. The highest storage amount of 969 mg/g has been obtained by using hexane as solvent and these drug release systems all have a sustained-release property. With the increase of the amount of functional groups introduced, the drug storage capacity decreases and meanwhile the release rate becomes lower. At the same amount of functional groups, the release rate from NNN-HMSC-IBU system (ibuprofen-loaded in NNN-TES modified HMSC) is the lowest. According to the Koorsmeyer-Peppas model, and it is found that the release process of HMSC-IBU system (ibuprofen-loaded in as-prepared HMSC) follows a Fick's law and modified HMSC-IBU systems follow an anomalous non-Fick's transport, respectively.