ABSTRACT
Many of the newer drugs undergoing development and entering the marketplace are proteins or peptides. These drugs are both highly potent and susceptible to hydrolytic and enzymatic degra dation in the gastrointestinal tract-characteristics that make them ideal candidates for par enteral controlled release formulation. For these formulations to be successful, however, they must not only deliver the therapeutic protein at the prescribed rate for the desired in vivo release period but also must preserve the activity of the protein during storage and release. Since pro teins are subject to a variety of degradation reactions both in solution and in the solid state, the preservation of activity is a central challenge in their formulation.
