Modified Montmorillonite as Drug Delivery Agent for Enhancing Antibiotic Therapy

Abstract

The appealing properties of surfactant-intercalated Montmorillonites (Organo-montmorillonite, OMt) were successfully investigated to propose an effective drug delivery system for metronidazole (MNE) antibiotic therapy. This represents a serious pharmaceutical concern due to the adverse drug reactions and the low targeting ability of MNE. The non-ionic surfactant Tween 20 was used to functionalize montmorillonite, thus accomplishing the two-fold objective of enhancing the stability of clay dispersion and better controlling drug uptake and release. The adsorption process was performed under different experimental conditions and investigated by constructing the adsorption isotherms through high-performance liquid chromatography (HPLC) measurements. Powder X-ray diffraction (XRD) measurements were performed to characterize the MNE/OMt compounds. The gathered results revealed that the uptake of the drug occurs preferentially in the clay interlayer, and it is governed by positive cooperative processes. The presence of surfactant drives the adsorption into clay interlayer and hampers the adsorption onto external lamella faces. The good performances of the prepared OMt in the controlled release of the MNE were proved by investigating the release profiles under physiological conditions, simulating oral drug administration. Cytotoxicity measurements demonstrated the biocompatibility of the complexes and evidenced that, under specific experimental conditions, nanodevices are more biocompatible than a free drug.