Thermal decomposition behavior of amino groups modified bimodal mesoporous silicas as aspirin carrier.

Two kinds of amino groups were employed to functionalize bimodal mesoporous silicas and related drug carriers were prepared. The characterization results of XRD, N2 adsorption and desorption, FT-IR and TG all confirmed the structural integrity of the bimodal mesopore architecture after introduction treatment of functional groups and the successful adsorption of aspirin. In order to investigate the interaction among the mesoporous structure, the functional groups grafted onto the mesoporous surface and the existential microenvironment of the drug molecules inside the mesoporous channels, the thermal decomposition behaviors of amino groups modified and aspirin loaded carriers were studied based on the thermogravimetric analysis in details. According to the thermogravimetry and derivative thermogravimetry results, the apparent activation energies E(a) of thermal decomposition for all related samples have been evaluated by Kissinger and Flynn-Wall-Ozawa methods. Meanwhile, their thermal decomposition mechanisms have been suggested by using Coats and Redfern methods. All these featured consequence could provide a deeper understanding for large loading capacity and controlled release of drug-carriers in the pharmaceutical application.