Protein and peptide drugs are used for treatment of a variety of ailments. However, their
wider use has been hindered by issues such as poor bioavailability in vivo and the cost
involved in producing these drugs. This review discusses the various carrier-mediated
methods used for delivery of peptide and protein drugs, with emphasis on liposomal
and microspherical drug delivery systems. A brief look at the types of peptidic drugs
currently in use clinically, and a brief discourse on several novel ideas for better protein
delivery systems for cancer therapy is included.