Characterization of gentamicin-bentonite complex

Clays are common ingredients in pharmaceutical and cosmetic formulations, used as active substances (gastrointestinal protector, osmotic oral laxatives, antidiarrhoeaics, topical antibacterials and antinflammatories) and excipients in solid (tablet, capsules, powder), liquid (suspensions, emulsions) or semisolid (ointments, creams) forms.Among the mineral clays, bentonite (BNT) has high specific surface area and it exhibits good adsorption ability, cation exchange capacity, standout adhesive ability and drug-carrying capability.The present work aims to evaluate the intercalation of gentamicin molecules into BNT clay to obtain a drug delivery carrier for antibiotic treatment in a perspective to decrease gentamicin side effects and to improve systemic adsorption.More, clay antibacterial activity could produce a synergistic effect.BNT-gentamicin hybrid was characterized by X-ray diffraction, Fourier transformed infrared, ultraviolet-visible spectroscopy, thermal analysis, differential scanning calorimetry and simulations molecular dynamics modelling.Molecular modeling can suggest an interaction between bentonite and gentamicin molecules producing a monolayer in the montmorillonite (the main mineral composing bentonite) interlayer; adsorbed gentamicin is hydrated having, probably, water molecules located between the siloxane surface and gentamicin molecules with a resulting layer periodicity of 14.22 Å.The result obtained demonstrated the ability of gentamicin to be intercalated within the BNT structure.