Controlled Release of Interleukin-2 from Biodegradable Microspheres

Abstract
We have evaluated the use of biodegradable poly(DL-lactide-co-glycolide) microspheres for the controlled release of interleukin-2 (IL-2) and its modified forms: succinyl IL-2 (SIL-2) and polyethylene glycol-modified IL-2 (PEG IL-2). We show that a microsphere formulation can be prepared from PEG IL-2 using HSA as an excipient which, after an initial burst, releases 2-3% PEG IL-2 per day in a bioactive form continuously over a 20- to 30-day period.