Study on formulation variables of methotrexate loaded mesoporous MCM-41 nanoparticles for dissolution enhancement

The aim of this study was to develop methotrexate loaded mesoporous MCM-41 nanoparticles for improved dissolution of methotrexate. The mesoporous MCM-41 nanoparticles act as carrier for drug and increase the solubility of the drug. In order to achieve this objective small pore size MCM-41 nanoparticles have been synthesized followed by drug loading process. The process of drug loading was optimized using full 3(3) factorial design. With a view to obtain maximum drug loading three variables, concentration of drug solution, stirring rate, and drug:carrier ratio were optimized using a full 3(3) factorial design. Using statistically designed experiments, the inclusion of methotrexate in MCM-41 nanoparticles was successfully carried out to obtain a drug loading of about 48%. X-ray powder diffraction and differential scanning calorimetry revealed the presence of methotrexate in amorphous form and FT-IR spectroscopy showed the presence of light interactions between the silicate silanols and the drug. The decrease of Brunauer, Emmett and Teller specific surface area and pore volume between free MCM-41 and the inclusion compound was the proof of the presence of methotrexate inside the mesopores. The inclusion compound was submitted to in vitro dissolution tests and a remarkable dissolution rate improvement was observed in comparison to the crystalline drug in all tested conditions. (C) 2011 Elsevier B.V. All rights reserved.