Ph-responsive magnetic mesoporous silica based bimodal drug delivery system for both anionic and cationic drugs

Abstract

In this study, pH-responsive drug delivery system was prepared by magnetic mesoporous silica synthesis through hydrothermal method followed by post-synthetic amino modification. The structure of the synthesized nanocomposite was characterized by XRD, FT-IR, VSM, XPS, TEM, SEM, N2-adsorption/desorption, and surface charge density analyses. The nanocomposite, which was determined to have a remarkably stable mesostructure and superparamagnetic character, was used as drug carrier for both anionic character Indomethacin (IND) and cationic character Doxorubicin (DOX). IND, an anti-inflammatory drug, and DOX, an anticancer drug used in chemotherapy, must be used in high doses due to their low water solubility and lack of targeting ability, respectively. The loading capacities determined according to the adsorption equilibrium are quite high for both drugs (106.96 and 134.10 mg/g, for IND and DOX, respectively) due to electrostatic attraction and hydrogen bond formation. For IND, the release study was realized in phosphate buffer solutions (pH 7.4, 6.8 and 2.2) by mimicking the gastrointestinal tract; for DOX, human blood pH (7.4) and cancer cell pH (5.5) were selected as the release medium. IND exhibited increased release behavior at neutral pH (7.4, 39.5% release), while DOX exhibited increased release behavior at acidic pH (5.5, 39.7% release). Peppas-Sahlin and Korsmeyer-Peppas kinetic models effectively described the IND and DOX release behavior from the nanocomposite. Both IND and DOX could be loaded with high loading efficiency (85.36% and 88.88% for IND and DOX, respectively) onto the nanocomposite and pH-controlled release can be achieved, which may be inspiring for a bimodal nanomedical treatment approach.