ABSTRACT
In the 1980s, the first long-term controlled-release peptide products were born, establishing the feasibility of controlling the release of small biomolecules. The polymer that was chosen for these products was the safe and biodegradable copolymer derived from lactic and glycolic acids [poly(lactic-co-glycolic acids) or PLGAs], which had an established safety record in clinically used resorbable sutures as well as numerous other desirable characteristics, including the ability to control the time-scale of bioerosion. Shortly thereafter, to meet the rapid growth in the number of protein
drugs entering clinical trials (1,2), a strong scientific interest followed to understand how to control the delivery of this special class of molecules from PLGAs. Frequent injections are standard practice for protein delivery because of the poor bioavailability from non-invasive routes (e.g., oral and transdermal) and the rapid clearance of proteins from the bloodstream.
