Preparation and application of monodispersed mesoporous submicron carbon particles as a drug carrier

Monodispersed mesoporous carbon (MMPC) submicron carbon particles have been fabricated by co-spray drying of SBA-15 submicron particles and sucrose, followed by carbonization in a nitrogen environment and removal of the hard SBA-15 template in NaOH solution. The ratio of sucrose/SBA-15 used for the co-spray drying affected the integration and dispersibility of the obtained mesoporous carbon particles and sucrose/SBA-15 ratios at 1.0–1.5 resulted in monodispersed mesoporous carbon submicron particles. The surface properties of MMPC could be modified by treatment in nitric acid solution to create oxygen groups and thus increase wettability of MMPC powder. MMPC particles were used as drug carrier to enhance the dissolution rate of a poorly soluble drug, indomethacin (IDMC) via co-spray drying. The morphology of MMPC was not changed after drug loading as most IDMC molecules were encapsulated into its pore channels in amorphous state, which was characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Due to the ordered mesoporous structure, the pore walls separate the IDMC particles and prevent recrystallization from happening. The amorphous IDMC/MMPC solid dispersion exhibited excellent stability under stress storage conditions of 40 °C/75% RH for six months. The amorphous formulation contributed to the significantly enhanced dissolution rate of IDMC from solid dispersion.