Incorporation and release of fluorescein isothiocyanate-linked dextrans from a bead-formed macroporous hydrophilic matrix with potential for sustained release.

Freeze-thaw polymerization has been used to generate a bead-formed (100-3000 microns) macroporous hydrophilic matrix with potential for the sustained release of macromolecules. While the incorporation of FITC-dextrans marginally increased the equilibrium water content, their in vitro release profiles were characterized by an initial burst followed by a low but sustained release lasting > 21 d. The total cumulative release of FD-150 and the percentage of the incorporated FD-150 load subsequently released were reduced compared with FD-20S but for both dextrans these parameters could be enhanced by increasing the bead size and increasing the incubation temperature to 37 degrees C.