Synthesis of zirconia/polyethylene glycol hybrid materials by sol-gel processing and connections between structure and release kinetic of indomethacin.

Controlled and local drug delivery systems of anti-inflammatory agents are attracting an increasing attention because of their extended therapeutic effect and reduced side effects. In this work, the sol–gel process was used to synthesize zirconia/polyethylene glycol (ZrO2/PEG) hybrid materials containing indomethacin for controlled drug delivery. Different percentages of PEG were introduced in the synthesis to modulate the release kinetic and an exhaustive chemical characterization of all samples was performed to detect the relationship between their structure and release ability. Fourier transform spectroscopy and solid-state NMR show that the Zr–OH groups of the inorganic matrix bond both the ethereal oxygen atoms of the polymer and the carboxylic groups of the drug. X-ray diffraction analysis ascertains the amorphous nature of those materials. Scanning electron microscopy detects the nanostructure and the homogeneous morphology of the synthesized materials. The bioactivity was demonstrated by the formation of a hydroxyapatite layer on the surface of the samples, after soaking in a simulated body fluid. The release kinetics study, performed by HPLC UV–Vis spectroscopy, proves that the release ability depends on PEG and the drug amount and also demonstrates the indomethacin integrity after the synthetic treatment. Controlled and local drug delivery systems of anti-inflammatory agents are attracting an increasing attention because of their extended therapeutic effect and reduced side effects. In this work, the sol-gel process was used to synthesize zirconia/polyethylene glycol (ZrO2/PEG) hybrid materials containing indomethacin for controlled drug delivery. Different percentages of PEG were introduced in the synthesis to modulate the release kinetic and an exhaustive chemical characterization of all samples was performed to detect the relationship between their structure and release ability. Fourier transform spectroscopy and solid-state NMR show that the Zr-OH groups of the inorganic matrix bond both the ethereal oxygen atoms of the polymer and the carboxylic groups of the drug. X-ray diffraction analysis ascertains the amorphous nature of those materials. Scanning electron microscopy detects the nanostructure and the homogeneous morphology of the synthesized materials. The bioactivity was demonstrated by the formation of a hydroxyapatite layer on the surface of the samples, after soaking in a simulated body fluid. The release kinetics study, performed by HPLC UV-Vis spectroscopy, proves that the release ability depends on PEG and the drug amount and also demonstrates the indomethacin integrity after the synthetic treatment

Geopolymer/PEG Hybrid Materials Synthesis and Investigation of the Polymer Influence on Microstructure and Mechanical Behavior

Geopolymers are aluminosilicate inorganic polymers, obtained from the alkali activation of powders containing SiO2+Al2O3>80wt%, mainly proposed as environmentally friendly building materials. In this work, metakaolin-based geopolymers have been prepared and a water-soluble polymer, polyethylene glycol (PEG), has been added in different percentages to obtain organic-inorganic hybrid geopolymers. The influence of both the polymer amount and aging time on the structure and the mechanical behavior of the materials were investigated. FTIR spectroscopy allowed us to follow the evolution of the aluminosilicate framework during the geopolymerization process. This analysis revealed that PEG leads to a network which is rich in Al-O-Si bonds and forms H-bonds with the inorganic phase. SEM microscope showed that the two phases are interpenetrated on micrometric scales. Traction and bending tests have been carried out on appropriate samples to investigate the mechanical behavior of the obtained hybrids, showing that both PEG content and aging time affect the material behavior

Surface Modifications for Implants Lifetime extension: An Overview of Sol-Gel Coatings

The limited lifetime of implants entails having patients undergo replacement surgeries, several times throughout life in young patients, with significant risks for them and extensive cost for healthcare service. The overcoming of such inconvenience is still today a hard challenge for the scholars of the biomedical and biomaterial fields. The improvement of the currently employed implants through surface modification by coatings application is the main strategy proposed to avoid implants failure, and the sol-gel coating is an ideal technology to achieve this goal. Therefore, the present review aims to provide an overview of the most important problems leading to implant failure, the sol-gel coating technology, and its use as a strategy to overcome such issues

Anti-inflammatory entrapment in Polycaprolactone/silica hybrid materials prepared by sol-gel route, characterization, bioactivity and vitro release behaviour

Aim: A novel organic/inorganic hybrid material, based on poly(ε-caprolactone) (PCL) and silica (SiO2), were synthesized by the sol-gel method. An anti-inflammatory agent (indomethacin) was incorporated into the hybrid material to verify its local controlled drug delivery system. Methods: The structure of the interpenetrating network was investigated by Fourier transform infrared spectroscopy. The morphology of the materials was studied by scanning electron microscopy. The structure of a molecular level dispersion was disclosed by atomic force microscopy. The bioactivity of the synthesized hybrid materials was revealed by the formation of a layer of hydroxyapatite on the surface of samples soaked in a simulated body fluid (SBF). Release kinetics in SBF were subsequently investigated. The amount of drug released was detected by UV-VIS spectroscopy. Results: Pure anti-inflammatory agent exhibited linear release with time; in contrast, sol-gel silica entrapped drugs were released with a logarithmic time dependence starting with an initial burst effect followed by a gradual decrease. Conclusions: SiO2/PCL (3, 6, 9 and 12%wt) materials, prepared via sol-gel process, are organic/inorganic hybrid and bioactive materials. All the materials showed a good release and therefore could be used as drug delivery syste

Anti-inflammatory entrapment in polycaprolactone/silica hybrid material prepared by sol-gel route, characterization, bioactivity and in vitro release behavior

Aim: A novel organic/inorganic hybrid material, based on poly(ε-caprolactone) (PCL) and silica (SiO2), were synthesized by the sol-gel method. An anti-inflammatory agent (indomethacin) was incorporated into the hybrid material to verify its local controlled drug delivery system. Methods: The structure of the interpenetrating network was investigated by Fourier transform infrared spectroscopy. The morphology of the materials was studied by scanning electron microscopy. The structure of a molecular level dispersion was disclosed by atomic force microscopy. The bioactivity of the synthesized hybrid materials was revealed by the formation of a layer of hydroxyapatite on the surface of samples soaked in a simulated body fluid (SBF). Release kinetics in SBF were subsequently investigated. The amount of drug released was detected by UV-VIS spectroscopy. Results: Pure anti-inflammatory agent exhibited linear release with time; in contrast, sol-gel silica entrapped drugs were released with a logarithmic time dependence starting with an initial burst effect followed by a gradual decrease. Conclusions: SiO2/PCL (3, 6, 9 and 12%wt) materials, prepared via sol-gel process, are organic/inorganic hybrid and bioactive materials. All the materials showed a good release and therefore could be used as drug delivery syste