Effect of aluminum content from mcm-41-type silica materials on the irinotecan adsorption and its in-vitro release

Two MCM-41-type aluminosilicate materials were employed as vehicles for the design of irinotecan-based delivery systems. The mesostructured supports were prepared via the sol-gel method combined with a hydrothermal treatment using tetraethyl orthosilicate as silicon source and aluminum sec-butoxide or sodium aluminate as aluminum precursor. The adsorption of the cytostatic agent on the studied carriers was performed by an impregnation procedure, while its in-vitro desorption was carried out in simulated body fluid (SBF – phosphate buffer solution, pH = 7.4). The drug uptakes (around 36%) and retention yields (around 90%) obtained for the aluminosilicates were higher than in the case of MCM-41 silica support. Also, slower delivery kinetics and lower values of the maximum cumulative release for aluminosilicate-type carrier were noticed. These phenomena were ascribed to the acidity induced by the presence of aluminum in the silica framework.