Preparation and characterization of octyl phenyl polyoxyethylene ether modified organo-montmorillonite for ibuprofen controlled release

Abstract To fabricate a hydrophobic pharmaceutical formulation with the use of montmorillonite (MMT), the strong polarity and structural properties of montmorillonite were modified by via simple and convenient wet ball-milling method using the nonionic surfactant, octyl phenyl polyoxyethylene ether, as the modifier, to improve the MMT's affinity to hydrophobic organic drug, ibuprofen. The resultant organo-montmorillonite (OPP-MMT) was characterized by the means of scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, thermogravimetric analyzer, BET-specific surface area measurements, drug adsorption and in vitro release experiments, and in vitro cell viability assay. Experimental results showed that octyl phenyl polyoxyethylene ether was successfully inserted into the interlayer of the raw Na-MMT during the wet ball-milling process. The adsorption and intercalation modification of octyl phenyl polyoxyethylene ether destroyed the rigid structure of Na-MMT, enlarged the interlayer spacing of Na-MMT, and enhanced its specific surface area, pore volume and mean mesopore size, which made it be more conducive to the loading of hydrophobic organic drugs. The adsorption analysis of OPP-MMT on ibuprofen showed that the affinity of OPP-MMT to hydrophobic drugs was better than that of Na-MMT, which was beneficial to the loading of ibuprofen. Moreover, the good affinity of OPP-MMT to hydrophobic drug allowed it to exhibit good controlled release properties for the drug delivery.