Temperature- and pH-sensitive terpolymers for modulated delivery of streptokinase
- 1 January 1997
- journal article
- Published by Taylor & Francis in Journal of Biomaterials Science, Polymer Edition
- Vol. 8 (2) , 119-129
- https://doi.org/10.1163/156856296x00192
Abstract
Controlled release devices were designed which respond to changes in pH and temperature by reversibly swelling and deswelling to control release of streptokinase. Copolymer hydrogels composed of N-isopropylacrylamide (NIPAAm) and methacrylic acid (MAA) as well as terpolymer hydrogels containing NIPAAm, acrylic acid (AA), and 2-hydroxyethyl methacrylate (HEMA) were synthesized. Hydrogels containing NIPAAm display a change in swelling behavior across the lower critical solubility temperature of PNIPAAm, whereas hydrogels with MAA and AA swelled only at high pH values due to the ionization of carboxylic pendant groups. HEMA was chosen as a third component to add mechanical strength and integrity to the hydrogel. Pulsatile pH- and temperature-dependent swelling studies were performed to determine the extent and rate at which the hydrogels swell in response to changing conditions. Results showed that increasing the NIPAAm concentration in the copolymers or terpolymers resulted in a higher degree of temperature...Keywords
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