title: Novel sol-gel organic-inorganic hybrid materials for drug delivery.
abstract: OBJECTIVE
  The aim of the present study was to synthetize and characterize novel sol-gel organic-inorganic hybrid materials to be used for controlled drug delivery application.
  
  
  METHODS
  Organic-inorganic hybrid class I materials based on poly(epsilon-caprolactone) (PCL 6, 12, 24 and 50 wt%) and zirconia-yttria (ZrO2-5%Y2O3) were synthesized by a sol-gel method, from a multicomponent solution containing zirconium propoxide [Zr(OC2H7)4], yttrium chloride (YCl3), PCL, water and chloroform (CHCl3). The structure of the hybrids was obtained by means of hydrogen bonds between the Zr-OH group (H-donor) in the sol-gel intermediate species and the carboxylic group (H-acceptor) in the repeating units of the polymer.
  
  
  RESULTS
  The presence of hydrogen bonds between organic-inorganic components of the hybrid materials was suggested by Fourier transform infrared (FTIR) analysis, and strongly supported by solid-state NMR. A single-step, sol-gel process was then used to precipitate microspheres containing ketoprofen or indomethacin for controlled drug delivery applications. Release kinetics in a simulated body fluid (SBF) were subsequently investigated. The amount of drug released was detected by UV-VIS spectroscopy. Pure anti-inflammatory agents exhibited linear release with time, in contrast drugs entrapped in the organic-inorganic hybrids were released with a logarithmic time dependence, starting with an initial burst effect followed by a gradual decrease.
  
  
  CONCLUSIONS
  The synthesis of amorphous materials containing drugs, obtained by sol-gel methods, helps to devise new strategies for controlled drug delivery system design.
authors.affiliation: Department of Mechanical and Aerospace Engineering, Second University of Naples, Aversa, Italy. michelina.catauro@unina2.it
authors.forename: Michelina
authors.initials: M
authors.lastname: Catauro
authors.forename: Duilio
authors.initials: D
authors.lastname: Verardi
authors.forename: Daniela
authors.initials: D
authors.lastname: Melisi
authors.forename: Federico
authors.initials: F
authors.lastname: Belotti
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Mustarelli
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use; D007213:Indomethacin / Q000008:administration & dosage / Q000627:therapeutic use; D015918:Infusion Pumps, Implantable; D007287:Inorganic Chemicals / Q000737:chemistry; D007660:Ketoprofen / Q000008:administration & dosage / Q000627:therapeutic use; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009930:Organic Chemicals / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D044367:Phase Transition; D011091:Polyesters / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D015040:Zirconium / Q000737:chemistry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007287:Inorganic Chemicals; D009930:Organic Chemicals; D010087:Oxides; D011091:Polyesters; C062968:lactide-caprolactone copolymer; D007660:Ketoprofen; D015040:Zirconium; D007213:Indomethacin