Tuesday, November 16, 2010

Block copolymers thermogelation

The below article shows the usage of thermosensitive block polymers for depot formation. Find these polymers at www.polyvivo.com, go to the link below or to the original source for full-text for the article. (note the below article did not not necessarily use an Akina product for this research). Abstract follows:

Aqueous solutions of poly(dl-lactic acid-co-glycolic acid)-g-poly(ethylene glycol) copolymers exhibited sol-to-gel transition with increasing temperature. Further increase in temperature makes the system flow and form a sol phase again. Subcutaneous injection of a copolymer aqueous solution (0.5 mL) resulted in a formation of a hydrogel depot by temperature-sensitive sol-to-gel transition in a rat model. The reliable determination and control of sol-to-gel transition temperatures are the most important issues for this kind of sol−gel reversible hydrogel. The sol-to-gel transition temperature determined by the test tube inverting method, falling ball method, and dynamic mechanical analysis coincided within 1−2 °C. Fine tuning of the sol-to-gel transition temperature was achieved by varying the ionic strength of the polymer solutions and by mixing two polymer aqueous solutions with different sol-to-gel transition temperatures. The sol-to-gel transition temperature of polymer mixture aqueous solutions was well described by an empirical equation of miscible blends, indicating miscibility of the two polymer systems in water on the molecular level.

Y.-M. Chung, K.L. Simmons, A. Gutowska, B. Jeong, "Sol-Gel Transition Temperature of PLGA-g-PEG Aqueous Solutions. Biomacromolecules 3(3) (2002) 511-516.

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