Ring-Opening Polymerization of Epoxy End-Terminated Polyethylene Oxide (PEO) as a Route to Cross-Linked Materials with Exceptional Swelling Behavior

We report here studies directed toward the synthesis and characterization of cross-linked poly(ethylene oxide) gels for use as drug delivery platforms. These gels were prepared by anionic ring-opening polymerization of diepoxy PEO400, PEO3400, and PEO8000 using t-BuOK as the initiator. The diepoxy PEO3400 and PEO8000 derived gels were found to swell to 20× and 30× their initial masses in water, falling in the category of superadsorbants. Evaluation of their behavior as disintegrants using lactose and calcium phosphate, in comparison with commercial disintegrant croscarmellose sodium, showed the diepoxy PEO3400 gel to be twice as fast in disintegrating a tablet. The diepoxy PEO3400 and PEO8000 derived gels were characterized by XRD, DSC, and TGA. and compared with the linear versions of the same materials. XRD powder patterns for all materials are very similar, albeit those for the gels are less intense likely because of packing disorders near cross-links. DSC data indicate that both Tm and Tc are consiste...