JCIS 421-2014-6

Variation of the crystal growth of mesoporous silica nanoparticles
and the evaluation to ibuprofen loading and release

Mesoporous silica nanoparticles (MSNs) were synthesized with variable microwave power in the range of
100–450 W, and the resulting enhancement of MSN crystal growth was evaluated for the adsorption and
release of ibuprofen. X-ray diffraction (XRD) revealed that the MSN prepared under the highest microwave
power (MSN450) produced the most crystallized and prominent mesoporous structure. Enhancement
of the crystal growth improved the hexagonal order and range of silica, which led to greater
surface area, pore width and pore volume. MSN450 exhibited higher ibuprofen adsorption (98.3 mg/g), followed
by MSN300 (81.3 mg/g) and MSN100 (74.1 mg/g), confirming that more crystallized MSN demonstrated
higher adsorptivity toward ibuprofen. Significantly, MSN450 also contained more hydroxyl
groups that provided more adsorption sites. In addition, MSN450 exhibited comparable ibuprofen adsorption
with conventionally synthesized MSN, indicating the potential of microwave treatment in the synthesis
of related porous materials. In vitro drug release was also investigated with simulated biological
fluids and the kinetics was studied under different pH conditions. MSN450 showed the slowest release
rate of ibuprofen, followed by MSN300 and MSN100. This was due to the wide pore diameter and longer
range of silica order of the MSN450. Ibuprofen release from MSN450 at pH 5 and 7 was found to obey a
zero-order kinetic model, while release at pH 2 followed the Kosmeyer–Peppas model.