Insight on the Dependence of the Drug Delivery Applications of Mesoporous Silica Nanoparticles on Their Physical Properties

Mesoporous silica nanoparticles (MSNs) are fascinating due to their interesting properties and applications. Purpose The optimization of MSNs for drug delivery applications was achieved by preparing different formulations of MSNs using different concentrations of ammonium hydroxide (NH4OH) (0.7, 1.4, 2.8, 4.2, and 5.6 mg/ml for MSN1, MSN2, MSN3, MSN4, and MSN5, respectively). Methods In the synthesis of MSNs, NH4OH was used as a catalyst while tetraethyl orthosilicate were used as a source of silica. Transmission electron microscopy (TEM) image revealed a linear increase in the size of the formed MSNs with increase in catalyst concentration. TEM images showed that all investigated nanoparticles were dispersed and spherical (changed to oval on addition of higher concentration of NH4OH). Results The hydrodynamic sizes of prepared MSNs were (64.18 +/- 6.8, 90.46 +/- 7.1, 118.98 +/- 7.01, 152.7 +/- 1.7, and 173.9 +/- 9.36 nm for MSN1, MSN2, MSN3, MSN4, and MSN5, respectively) assessed using the dynamic light scattering (DLS) technique. The negative values of zeta potential indicated high surface stability of the formed MSNs. N-2-isotherm revealed that the pore volume of MSNs decreased with increase in the size of MSNs. In vitro drug release showed that all MSNs exhibited high encapsulation efficiency of doxorubicin. The encapsulation efficiency were 92.2%, 82.8%, 72.2%, 72.1% and 71.9%for MSN1, MSN2, MSN3, MSN4, and MSN5, respectively. Conclusion MSN1 and MSN2, with sizes of 64.18 +/- 6.8 and 90.46 +/- 7.1 nm, pore volume of 0.89 and 0.356 cc/g, encapsulation efficiency of 92.2% and 82.8%, and adequate drug release profiles, were probably the best choices for a drug carrier in drug delivery applications.