Patent ID: 7842305

Claim:
A method of preparing a biodegradable dual pore polymer scaffold, the method comprising: i) preparing a polymer solution by dissolving a biodegradable polymer in a mixture of an organic solvent capable of dissolving the biodegradable polymer and a non-solvent that is miscible with the organic solvent but that is incapable of dissolving the biodegradable polymer, adding an effervescent mixture of a carbonate and an organic acid thereto, and mixing the resulting mixture, wherein the effervescent mixture comprises particles having a particle size in the range from 5 μm to 40 μm for forming small pores and particles having a particle size in the range from 100 μm to 500 μm and, wherein the organic solvent is selected from the group consisting of methylene chloride, chloroform, carbon tetrachloride, acetone, dioxane, tetrahydrofuran, dichloromethane, and mixtures thereof, and wherein the non-solvent is selected from the group consisting of water, ethanol, methanol, and mixtures thereof; then ii) forming a polymer sample by drying the polymer solution obtained in step i) and evaporating said mixture of organic solvent and the non-solvent, thereby forming a plurality of small pores in the polymer sample; and then iii) adding said polymer sample obtained in step ii) to a mixed solution of water and alcohol and then drying the resulting substance, the mixed solution causing the effervescent mixture in the polymer to effervesce and form a plurality of large pores in the polymer sample, thereby providing a biodegradable dual pore polymer scaffold with small pores interconnected with the large pores.