MSNCs and MgO-MSNCs as drug delivery systems to control the adsorption kinetics and release rate of indometacin

Mesoporous silica cocoon materials (MSNCs) and MgO doped mesoporous silica cocoons (MgO-MSNCs) with the cocoon-like hierarchical morphology and different alkalinities were synthesized as carriers for acidic drugs. Indomethacin (IMC) was selected as a model drug and loaded into carriers. All materials and the drug-loaded samples were characterized by nitrogen adsorption, FTIR spectroscopy, transmission electron microscopy (TEM), powder X-Ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of the Mg/Si molar ratio on the kinetics and equilibrium of IMC adsorption on MgO-MSNCs was thoroughly examined, and it was found that the increase in the Mg/Si molar ratio resulted in an increasing IMC adsorption rate due to the increased affinity between alkaline MgO-MSNCs and weak acid IMC. The adsorption kinetics fitted a pseudo second-order model well. The Freundlich isotherm showed a better fit, indicating that the coverage of IMC on the surface of MgO-MSNCs was heterogeneous. The maximum adsorption capacity of adsorbent was calculated by the Langmuir isotherm equation. The Temkin equation provided further support that the IMC adsorption on MgO-MSNCs was dominated by a chemisorption process. MgO-MSNCs also have the advantage of allowing an adjustment of the drug release rate of weak acid drug. The cytotoxicity assay indicated good biocompatibility of MgO-MSNCs. Our research on MgO-MSNCs carriers demonstrated their potential therapeutic benefit for safe and effective management of IMC adsorption and in vitro release.