In vitro release of dextran sulfate from silicone intravaginal rings

Abstract 02665

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.

Persistence of antimicrobial activity through sustained release of triclosan from pegylated silicone elastomers

Microbial adhesion to silicone elastomer biomaterials is a major problem often resulting in infection and medical device failure. Several strategies have been employed to modulate eukaryotic cell adhesion and to hamper bacterial adherence to polymeric biomaterials. Chemical modification of the surface by grafting of polyethylene glycol (PEG) chains or the incorporation of non-antibiotic antimicrobial agents such as triclosan into the biomaterial matrix may reduce bacterial adhesion. Here, such strategies are simultaneously applied to the preparation of both condensation-cure and addition-cure silicone elastomer systems, seeking a sustained release antimicrobial device biomaterial. The influence of triclosan incorporation and degree of pegylation on antimicrobial release, surface microbial adherence and persistence (Escherichia coli and Staphylococcus epidermidis) were evaluated in vitro. Non-pegylated silicone elastomers provided an increased percentage release of triclosan extending over a relatively short duration (99% release by day 64) compared with their pegylated (4% w/w) counterparts (65% and 72% release by day 64, for condensation and addition-cure systems respectively). Viable E. coli adherence to a non-pegylated silicone elastomer containing 1% w/w triclosan was reduced by over 99% after 24 h compared to the non-pegylated silicone elastomer containing no triclosan. No viable S. epidermidis adhered to any of the triclosan-loaded (>0.1% w/w) formulations other than the control. Persistence of the antimicrobial activity of the triclosan-loaded pegylated silicone elastomers continued for at least 70 days compared to the triclosan-loaded non-pegylated elastomers (at least 49 days). Understanding how PEG affects the release of triclosan from silicone elastomers may prove useful in the development of a biomaterial providing prolonged, effective antimicrobial activity.