The Effect of Temperature on Controlled Release of Heparin From Polyurethane and Ethylene Vinyl Acetate Copolymer

The objectives of this study were to examine the effect of elevated temperatures on the release kinetics of heparin from polyurethane (PU) and ethylene vinyl acetate copolymer (EVA), and on the biological activity of heparin released from the polymer matrix. Monolithic samples, prepared by dispersing heparin in solutions of PU and EVA, were fabricated and evaluated for in vitro release rates. Comparisons were made on the release rate of heated and non-heated samples. Heating at 120°C had little effect on the release kinetics from PU and an increase on release from EVA. Bioactivity of pure heparin and heparin released from PU was also evaluated and were found to remain stable up to 210°C.