Smectite as ciprofloxacin delivery system: Intercalation and temperature-controlled release properties

Clays have shown to be good candidates as drug delivery carriers. In the present paper, the temperature-dependent swelling of smectites was exploited to obtain composites able to release a drug in a controlled way. More specifically, synthetic fluorohectorite-ciprofloxacin composites were prepared, in which the drug molecules were intercalated between the clay layers. The drug-release systems were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), ultraviolet spectroscopy (UV) and atomic absorption spectrometry (AAS). The results from the X-ray diffraction allowed confirming the ciprofloxacin incorporation into the interlayer space, and the results from UV spectroscopy indicated that more than 90% of the initial drug was uptaken by the clay. The thermally activated drug release from a colloidal dispersion of nanosized composite particles in both pure water and synthetic gastric juice was evaluated at temperatures from 37 °C (body temperature) to 85 °C. The studies indicated that the clay promotes the slow release of ciprofloxacin, and that the release of drug increases with both time and temperature. The profiles of drug-release from the clay fulfilled the pharmaceutical standards for these systems. As a result, a clay-based Temperature-Controlled Release System (TCRS) with potential biomedical applications has been obtained