Many pharmaceuticals have limited solubility in water, which poses a challenge in drug-delivery. The focus of our research is the synthesis of new, amphiphilic star block copolymers that have hydrophobic polylactide (PLA) blocks attached to hydrophilic polyethylene glycol (PEG) blocks. These molecules have the potential to form micelles that might facilitate the delivery of pharmaceuticals. Specifically, four-armed calixarene-core PLA/PEG star block copolymers have been synthesized. To produce the copolymers, star polymers with 20 and 30 repeat units of PLA/arm were made by ring-opening polymerization of lactide using a calixarene initiator. Alkynes were then attached to the PLA chain ends, followed by a click reaction to attach PEG to the alkynes. No-D NMR spectroscopy was used to determine the reactant ratios needed for successful completion of the click reactions. The synthesis of 20 and 30 repeat unit PLA/PEG star polymers was successful. Studies were carried out to test the 20 repeat unit PLA/PEG's ability to solubilize a model fluorescent dye, coumarin-6 (C6). C6 has very limited solubility in water, which parallels the solubility of many drug molecules, e.g., paclitaxel. The presence of a yellow color and fluorescence from C6 in aqueous solutions of the polymer suggests that micelles are formed that have the ability to solubilize molecules with low water solubility.

Calixarene-core star polymers: Building blocks for micelles and drug delivery

253rd National Meeting (2017)

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