The present invention provides a biocompatible composition that comprises a bioactive material and a method for using the same. In particular, the composition of the invention is useful for spatio and/or temporal release of the bioactive material. Specifically, the composition of the invention comprises at least one polymeric mixture layer comprising a plurality of biodegradable polymers. The polymeric mixture layer comprises a first biodegradable polymer and a second biodegradable polymer. The relative amount of the first biodegradable polymer or the second biodegradable polymer increases within the polymeric mixture layer in one direction, and the relative amount of the other biodegradable polymer decreases in the polymeric mixture layer in the same direction. The rate of degradation of the first biodegradable polymer is different from the rate of degradation of the second biodegradable polymer. In this manner, the composition allows spatio and/or temporal release of the bioactive material.
