Effect of mesopores on solidification of sirolimus self-microemulsifying drug delivery system

To investigate the influence of mesopores towards the solidification of self-microemulsifying drug delivery system (SMEDDS), mesoporous silica nanospheres (MSNs) and Santa Barbara Amorphous-15 (SBA-15) were compared. The MSNs had hydrodynamic size of 195.35 ±5.82 nm, and pore diameter of 2.70 nm. The SBA-15 had hydrodynamic size of 2312.19 ±106.93 nm, and pore diameter of 10.91 nm. The MSNs and SBA-15 showed similar loading efficiency of SMEDDS containing sirolimus (SRL). However, MSNs had higher drug dissolution and in vivo absorption, with relative bioavailability of 174.62%. Thus, the length of mesopores played a more important role in solidification of SMEDDS as compared with the pore diameter. This study suggests that the SMEDDS-MSNs can be a potential candidate for oral administration of hydrophobic drugs.