Synthesis of mesoporous spherical silica via spray pyrolysis: Pore size control and evaluation of performance in paclitaxel pre-purification

Spherical silica particles with various pore sizes were synthesized by spray pyrolysis using organic templates (CTAB, P123) and PS nanoparticles. The performance of the prepared silica was evaluated as an absorbent for the removal of impurities in the pre-purification processes of paclitaxel from plant-derived cell cultures. From the investigation of the synthetic temperature effect, it was found that the drying-zone temperature rather than the pyrolysis temperature greatly affects the change in the surface area of silica. At the optimal temperatures, the CTAB templates formed hexagonal-structured pores like MCM-41, whereas the silica synthesized using other templates (P123, CTAB/P123, PS nanoparticles) showed a random pore structure. By changing the template types, the pore size and the surface area of silica were controlled from 2.4 nm to 24.4 nm and from 131 m(2)/g to 1670 m(2)/g (CTAB), respectively. According to the evaluation of the adsorbent properties, the pore size rather than the surface area of silica was found to play a more important role in the pre-purification of paclitaxel. In terms of achieving the high purity and yield of paclitaxel, it was concluded that silica should have 8-15 nm in pore size, with as high a surface area as possible. Finally, we confirmed that the mesoporous silica synthesized by spray pyrolysis has better performance than the commercialized sylopute. (C) 2012 Elsevier Inc. All rights reserved.