Implantable medical device with varied composition and porosity, and method for forming same

A method for forming a unitary article, comprising the following steps:

• i. assembling two or more parts with complementary mating surfaces to form an article assembly, at least one of the two or more parts with complementary mating surfaces including at least one porogen;
• ii. compression molding the article assembly to form a unitary article free from discernible boundaries between portions of the unitary article derived from the two or more parts with complementary mating surfaces;
• iii. optionally forming additional features in the unitary article;
• and
• iv. leaching the at least one porogen from the unitary article,
• wherein at least one of the two or more parts with complementary mating surfaces is formed by:
• dispensing a powder blend into at least one mold, the powder blend including:
• at least one polymer powder;
• the at least one porogen in powder form;
• and
• optionally, at least one inorganic particle powder;
• compacting the powder blend in the at least one mold to form at least one preform.

A method for forming a unitary article, comprising the following steps:

• i. assembling two or more parts with complementary mating surfaces to form an article assembly, at least one of the two or more parts with complementary mating surfaces including at least one porogen;
• ii. compression molding the article assembly to form a unitary article free from discernible boundaries between portions of the unitary article derived from the two or more parts with complementary mating surfaces;
• iii. optionally forming additional features in the unitary article;
• and
• iv. leaching the at least one porogen from the unitary article.