Encapsulation of proteins for improved delivery.

Two recent advances have enabled the development of clinically useful, injectable, sustained-release protein formulations. The first is a nonaqueous, cryogenic atomization process that encapsulates the protein into microspheres composed of a biodegradable polymer from which the protein is released slowly. The second consists of numerous ways of maintaining protein stability within the microspheres for extended periods after injection. In addition to allowing less frequent administration of protein drugs, at possibly lower overall doses, it is possible that sustained-release formulations will justify commercial development of proteins that could not be marketed as solution formulations.