In situ SAXRD study of sol–gel induced well-ordered mesoporous bioglasses for drug delivery

In this work, two systems of mesoporous bioglasses (MBGs) were sol–gel derived using block copolymer pluronic F127 and P123, respectively, as templates. A two-dimensional hexagonal (P6mm) mesoporous structure was obtained for the two systems, with d-spacing in (100) reflection of 8.49 nm for P123-templated MBG (P123-MBG) and 10.26 nm for F127-templated MBG (F127-MBG). The phase transformation behavior for the systems was elucidated using an in situ synchrotron small angle X-ray diffraction approach, with the corresponding mechanisms proposed. It was indicated that both systems go through a complicated phase transformation, from a disordered to a finely ordered hexagonal structure during the self-evaporation process. The surfactants not only acted as templates for the ordered structure, but also enhanced the rigidity of Si—O network, which prevented disruption to the ordered Si—O arrangement by the Ca²⁺ and P—O group. In vitro bioactivity study showed similar bioactivity for both the P123-MBG and F127-MBG systems. Drug loading and release studies using a model metoclopramide drug showed that both MBGs presented better loading and release compared to normal bioglass (BG). The significantly higher loading and better sustained release for P123-MBG, compared to F127-MBG, is attributed to its higher pore volume and surface area. © 2007 Wiley Periodicals, Inc.