Sustained interferon-γ delivery from a photocrosslinked biodegradable elastomer

The application of protein therapeutics for long-term, localized delivery has been hindered by a lack of a delivery device that releases active protein at a concentration within their therapeutic window. A protein delivery system that uses an osmotic pressure delivery mechanism and a photocrosslinked biodegradable elastomer has been designed in an attempt to overcome this limitation. The elastomer is prepared through the UV initiated crosslinking of end terminal acrylated star-poly(ε-caprolactone-co-d,l-lactide). Interferon-γ (IFN-γ) was released from the optimum formulation at a constant rate of 23 ng/day over 21 days. A cell-based assay showed that over 83% of released IFN-γ was bioactive. Furthermore, it was demonstrated that bovine serum albumin co-lyophilized with IFN-γ was released at the same rate as IFN-γ. This delivery formulation may be clinically useful for sustained, local protein drug delivery applications.