Preparation and Characterization of Rifampin Loaded Mesoporous Silica Nanoparticles as a Potential System for Pulmonary Drug Delivery

The goal of this research is to determine the feasibility of loading rifampin into mesoporous silica nanoparticles. Rifampin was selected as a model lipophilic molecule since it is a well-documented and much used anti tuberculosis drug. The mesoporous silica nanoparticles were prepared by using Tetraethyl ortho silicate and cetyltrimethyl ammonium bromide (as surfactant); The prepared nanoparticles were characterized in terms of their particle size measurement and porosimetry. The results showed that the particle size is 218±46 nm (mean± SD) and surface area is 816 m2g-1 . In order to load rifampin within the mesopores, adsorption experiments using three different solvents (methanol, water and dimethyl sulfoxide) were carried out. The loading procedure results in a significant improvement of the amount of rifampin loaded into mesoporous silica nanoparticles and methanol was found to be a suitable solvent providing a drug entrapment efficiency of 52 %. Rifampin loaded nanoparticles underwent different in-vitro tests including: SEM and Drug release. The in vitro drug release was investigated with buffer phosphate (pH=7.4). Regarding the drug release study a biphasic pattern of release was observed. The drug-loaded mesoporous silica nanoparticles was capable of releasing 100% drug content after 24h following a burst effect in the first four hours. The prepared rifampin loaded nanoparticles seem to have potential for use in a pulmonary drug delivery.