Resorbable structure for treating and healing of tissue defects

Abstract

Devices and processes (e.g., improved Plasticized Melt Flow processes (PMF) or improved Phase Separation Polymer Concentration (PSPC), etc.) used to make resorbable and non-resorbable structures for treating and / or healing of tissue defects are disclosed. Among the advantages of using these improved processes are the preservation of molecular weight and the broadening of the processing conditions for temperature sensitive polymers and therapies (e.g. polylactide, polyglycolide, polycaprolactone or Cisplatin, etc.). This reduction in processing temperature, pressure and time can help to preserve the molecular weight and / or integrity of the final product or any additive incorporated therein. Additionally, pore size and shape tailoring can increase the osteoconductive nature of the device.

Description

RELATED APPLICATIONS [0001] This application is a Continuation of U.S. patent application Ser. No. 10 / 222,593, filed Aug. 15, 2002 in the names of Douglas G. Evans et al., which application is a Continuation of U.S. patent application Ser. No. 10 / 190,249, filed on Jul. 6, 2002, entitled Resorbable Structure for Treating and Healing of Tissue Defects.BACKGROUND OF THE INVENTION [0002] Tissue defects are sometimes repaired with porous scaffolds comprising biocompatable materials. The porous nature of the devices allows the inward migration of cells, followed by the in-growth of tissue, thereby repairing the defect. The pore structure must be controlled to ensure optimal inward cell migration (e.g., sized large enough to accommodate cells, and avoid altering the cell phenotype), from which the new tissue may form. Current devices do not adequately control pore geometry, size, and distribution, with processes that are economically attractive. Additionally, open porous networks facilitat...

AI Technical Summary

Benefits of technology

[0021] Certain polymers are very thermally sensitive and extended residence time within melt processing equipment (e.g., PMF equipment) can lead to extensive molecular weight degradation. Other polymers have very narrow processing windows where on the high end of a narrow range the polymer burns and on the low end of the range the polymer does not flow effectively and high stress conditions are created in the final part. By using a gas or solvent to plasticize the polymer, processing temperatures, pressures and time can be reduced. For example, when processing resorbable polymers (e.g. polylactide, polyglycolide, polycaprolactone, etc.), this reduction in processing temperature, pressure and time can help to preserve the molecular weight of the final product. By using described processes for this invention, these polymers can be used for creating large low-stress mass-produced resorbable medical devices.

[0044] Additional materials may also be used at the time of manufacture to control the process output (e.g. plastisizers, surfactants, dyes, etc.) For example, processing the polymer with stearic agents will cause the thinning of matrix between the pores, which is most easily penetrable, or rapidly resorbing, following implantation. This will result in a device with high strength, and interconnected pores, which will afford easier migration of cells through the implant.

Problems solved by technology

Certain polymers are very thermally sensitive and extended residence time within melt processing equipment (e.g., PMF equipment) can lead to extensive molecular weight degradation.

Other polymers have very narrow processing windows where on the high end of a narrow range the polymer burns and on the low end of the range the polymer does not flow effectively and high stress conditions are created in the final part.

Images