Release from polymeric prodrugs: linkages and their degradation.

Polymeric prodrugs have evolved into a very useful class of drug delivery agents. Numerous polymeric prodrugs have been prepared for applications ranging from passive drug targeting to controlled release. The mechanistic aspects of the release processes, however, have not been clearly delineated. This review highlights the salient features of the chemical reactions that are responsible for drug release from these systems. The mechanisms of release from polymeric prodrugs employing various chemical linkages, esters, carbonates, carbamates, C=N linkage and amides, are discussed. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1962-1979, 2004