PEG-hidrojel kaplı silika aerojel-Yeni bir ilaç taşınım sistemi

A novel composite of silica aerogel and poly (ethylene glycol) PEG hydrogel was synthesized and its potential as a drug delivery system were investigated. The composite was synthesized by encapsulation of hydrophobic aerogels within PEG hydrogel via photoinitiated polymerization. Disks of aerogels were synthesized by the two step sol-gel method using tetraethylortosilicate (TEOS) as the silica precursor. After the gels were aged in ethanol, the alcogels were then contacted with a solution of eosin-Y, a photoinitiator, dissolved in ethanol. The adsorption of eosin-Y onto the surface of alcogel led to a reddish transparent composite of silica aerogel with eosin-Y. The surface of eosin functionalized silica aerogels was then rendered hydrophobic using hexamethyldisilazane (HMDS) as the surface modification agent, and supercritical carbon dioxide (ScCO2) as solvent. Hydrophobicity of aerogel was tuned by changing HMDS amount dissolved in ScCO2 phase which changes the contact angle between 0-128o. Hydrophobic or hydrophilic aerogels were then dipped into a PEG diacrylate prepolymer solution, and photopolymerization was carried out using visible light (514 nm). BET surface area and pore size distribution measurements show that both hydrogel encapsulation and eosin-Y loading did not affect the pore structure of the aerogel.The potential of this novel composite as a drug delivery system was tested by Ketoprofen as a model drug. The results demonstrate that both drug loading capacity and drug release profiles could be tuned by changing hydrophobicity of aerogels, and that drug loading capacity increases with decreased aerogel hydrophobicity while slower release rates are achieved with increased hydrophobicity from eosin functionalized aerogels. The effect of PEG concentration (0, 15 %, and 30 % w/w) in the prepolymer solution of the hydrogel coating on drug release rate from hydrophilic aerogel was also investigated. It was seen that as the PEG concentration increased, the drug release was retarded. The experimental results showed that drug release can be controlled with this novel aerogel-hydrogel composite system via changing hydrophobicity of the aerogel, and the concentration of the PEG in the hydrogel coating.