Browsing by Author "Suggs, Laura J."

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    Development of poly(propylene fumarate-co-ethylene glycol): An injectable, biodegradable implant for cardiovascular applications
    (1998) Suggs, Laura J.
    A novel block copolymer consisting of poly(propylene fumarate), PPF, and poly(ethylene glycol), PEG, was fabricated and evaluated for use as a cardiovascular stent to prevent reclosure of the vessel lumen following balloon angioplasty. This copolymer has been fabricated in a block configuration with two to three homopolymer units in series through a transesterification reaction between the linear polyester and the terminal hydroxyl functionalities of the PEG. This material has been characterized in terms of structure and composition as well as thermal properties and solubility behavior. We described the preparation and bulk characterization of crosslinked P(PF-co-EG) hydrogels. The extent of the crosslinking reaction and the degree of swelling in aqueous solution were determined on several different copolymer formulations. Mechanical properties were evaluated and were shown to increase with increasing PPF molecular weight and decrease with increasing PEG content. The degradation behavior was examined in vitro at pH 7.4 and in vivo in a subcutaneous rat model, in terms of mass loss, dimensional changes, mechanical properties, morphology, and biocompatibility over a twelve week time course. The P(PF-co-EG) hydrogels demonstrated a pattern typical of bulk degradation. They retained at least a 20% of their initial ultimate tensile stress after three weeks with no apparent changes in morphology. Platelet adhesion and aggregation on P(PF-co-EG) hydrogels was examined under both static and flow conditions. We demonstrated a significant decrease in platelet attachment on the copolymer hydrogel films relative to PPF. In addition, there were also reductions in attachment resulting from an increase in PEG weight percent or molecular weight. The copolymer surfaces showed no thrombus formation or platelet spreading.
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    Method of making poly(propylene fumarate-coethylene oxide)
    (1997-07-01) Suggs, Laura J.; Payne, Richard G.; Yaszemski, Michael J.; Mikos, Antonios G.; Rice University; United States Patent and Trademark Office
    A biodegradable block copolymer made from the transesterfication of a poly(propylene fumarate) prepolymer and a poly(ethylene oxide) prepolymer. The block copolymer poly(propylene fumarate -co- ethylene oxide) is capable of crosslinking at body temperature. Crosslinking requires an appropriate crosslinking monomer and an initiator. The biodegradable block copolymer has utility as a vascular implant became it can be injected as a fluid into the vascular system and crosslinked in situ.
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    Synthesis of poly(propylene fumarate) by acylation of propylene glycol in the presence of a proton scavenger
    (2002-03-12) Peter, Susan J.; Suggs, Laura J.; Engel, Paul S.; Mikos, Antonios G.; Rice University; United States Patent and Trademark Office
    High molecular weight linear poly(propylene fumarate) having a relatively low polydispersity index by utilizing a relatively pure intermediate and a method for making same. Fumaryl chloride and propylene glycol are reacted in the presence of potassium carbonate. The potassium carbonate present in the reaction solution prevents the acid by-product from catalyzing reactions at the fumarate double bond. The bis(propyl fumarate) produced according to this technique can be transesterified using conventional processing steps to yield P(PF). The P(PF) produced from bis(propyl fumarate) produced according to the present method has a higher molecular weight and is purer than P(PF) produced using previously known techniques.