Effect of the incorporation of hydroxy-terminated liquid silicones on the cure characteristics, morphology and release of a model protein from silicone elastomer covered rods
MetadataShow full item record
Silicone elastomer systems have previously been shown to offer potential for the sustained release of protein therapeutics. However, the general requirement for the incorporation of large amounts of release enhancing solid excipients to achieve therapeutically effective release rates from these otherwise hydrophobic polymer systems can detrimentally affect the viscosity of the precure silicone elastomer mixture and its curing characteristics. The increase in viscosity necessitates the use of higher operating pressures in manufacture, resulting in higher shear stresses that are often detrimental to the structural integrity of the incorporated protein. The addition of liquid silicones increases the initial tan δ value and the tan δ values in the early stages of curing by increasing the liquid character (G″) of the silicone elastomer system and reducing its elastic character (G′), thereby reducing the shear stress placed on the formulation during manufacture and minimizing the potential for protein degradation. However, SEM analysis has demonstrated that if the liquid character of the silicone elastomer is too high, the formulation will be unable to fill the mold during manufacture. This study demonstrates that incorporation of liquid hydroxy-terminated polydimethylsiloxanes into addition-cure silicone elastomer-covered rod formulations can both effectively lower the viscosity of the precured silicone elastomer and enhance the release rate of the model therapeutic protein bovine serum albumin.
Showing items related by title, author, creator and subject.
Hardjito, Djwantoro (2005)The use of Portland cement in concrete construction is under critical review due to high amount of carbon dioxide gas released to the atmosphere during the production of cement. In recent years, attempts to increase the ...
Development of polylactide and polyethylene vinyl acetate blends for the manufacture of vaginal ringsMcConville, Christopher; Major, Ian; Friend, David; Clark, Meredith; Woolfson, A; Malcolm, R (2012)Vaginal rings are currently being investigated for delivery of HIV microbicides. However, vaginal rings are currently manufactured form hydrophobic polymers such as silicone elastomer and polyethylene vinyl acetate (PEVA), ...
Li, Chao (2012)The purpose of this dissertation was to synthesize and evaluate porous poly(2- hydroxyethyl methacrylate) (PHEMA) and PHEMA composite hydrogels containing various concentrations of titanium dioxide (TiO2) nanoparticles, ...