Supramolecular gels based on a gemini imidazolium amphiphile as molecular material for drug delivery

A novel physical gel was obtained using a gemini imidazolium-based amphiphilic molecule dissolved in ethanol-water mixtures. The structure of the gel is comprised of intertwining nanofibres with widths of approximately 80 nm. The ethanol/water ratio has an important influence on the gelation process: the gelator is sparingly soluble in water and soluble in ethanol. The gelator is capable of incorporating anionic drugs in its fibrillar network easily; sodium ibuprofenate, indomethacin and the sodium salt of methotrexate were used as model drugs that were incorporated into the quickly forming gels. The characterization of these composite xerogels was made by different microscopy techniques as well as X-ray powder diffraction. The ability of the amphiphile to form a gel is largely maintained in the presence of the different model drugs and the overall morphology of the gels (that present a fibre like structure in all cases with intertwined ribbons) is very similar. Furthermore the in vitro release of the drugs from the gel and the in vivo anti-inflammatory efficacy was studied. The overall results show better release profiles and anti-inflammatory efficacy for indomethacin, and prove the promise of this molecular gel in controlled drug release, in the present case dermatological application.