Drug delivery vehicle dextran release

Microgel particles consisting of vinylpyrrolidinone copolymerized with acrylic acid have been prepared (61). These particles were designed to be used as an oral drug delivery vehicle. The microgel particles were loaded with a marker compound fluorescein isothiocyonate (FITC)-dextran and the release of this compound was monitored as a function of pH and temperature. The release of this compound was found to be slow in an acid solution but increased rapidly as the pH was increased. There was also a subsequent increase in FITC-dextran release when the particles were heated. At 4°C 18% of the FITC-dextrans were released while 50% was released at 37°C. The increase in the amount of FITC-dextran released is due to the microgel shrinking when heated. 

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