Abstract: A new series of degradable polymeric matrices were prepared by blending polymers that degrade by hydrolysis such as poly(L-lactic acid)(PLA), and nonionic Pluronic.TM. surfactants, block copolymers of polyethyleneoxide (PEO) and polypropyleneoxide (PPO). The water content of the polymer blend films was controlled by mixing different types of block copolymers and by adjusting their amount. In aqueous solution, the blends revealed the typical liquid-crystalline phase transition of Pluronic.TM. polymers, suggesting the formation of a gel-like structure within the polymer skeleton. Poly(lactic acid) degradation rates were not affected by the blending procedure, although the hydration degree in these matrices was higher. When used as drug-releasing matrices, these blends extended protein release and minimized the initial protein burst, as compared to the pure polymer.