A microprojection array comprising an approximately planar base and a plurality of microprojections, wherein the array comprises a therapeutic macromolecule and a stabilizing excipient. Described herein are microstructures having a proximal and distal layer, wherein the distal layer which contains the therapeutic molecule does not rely on the presence of a structure-forming polymer to impart the mechanical strength necessary to penetrate the skin. Methods of forming the array, and methods of using the array are contemplated.
