Polymeric protein delivery systems

Although various peptide and protein drugs have been developed for therapeutic purposes, several challenges can still be encountered, including a relatively short half-life within the body. Use of an appropriate delivery carrier, which can protect protein drugs from enzymatic degradation and control release, is a promising approach for prolonged retention and biological activity of the drugs within the body. Polymers are attractive protein drug delivery carriers, as their properties, such as physical and chemical, can easily be modified and changed. A number of approaches have been reported on the controlled release of protein drugs using polymeric carriers. Unfortunately, no single polymer or formulation has been considered ideal for all types of protein drugs and approaches. In this review, potential and currently used polymers for fabrication of hydrogels or polymer-modified liposomal systems and their protein delivery applications will be discussed.