Aqueous solution of PEO-PPO-PEO triblock copolymer has been studied as a drug delivery system since it shows temperature sensitive sol gel transition. However, the disadvantages of this block copolymer system are the non-degradability and toxicity, which are important factors in drug delivery.
In this study, the PEO-polyalkylene succinate-PEO triblock copolymers were prepared with systematically varying the molecular weight, the relative hydrophobicity, and the crystallinity of the polyester block. Polyalkylene succinate was synthesized from succinic acid(SA) and diol. Ethylene glycol, 1,3 propanediol, and 1,4 butanediol were used in this study. The aqueous solution of the triblock copolymer showed gel-sol transition behavior, which was confirmed by the vial tube tilting method. The micellization was also investigated by the dynamic light scattering and UV visible spectrophotometer. With increasing the molecular weight and the hydrophobicity of polyester midblock, the minimum concentration to form the gel decreased due to the increase of the micelle volume. The increase in crystallinity also led to the decrease of the minimum concentration to form the gel.
