Application and Drying of Protein Drug Microdroplets on Solid Surfaces

Abstract

A new method to apply small amounts of protein drug solutions in the form of microdroplets to surfaces and to dry them is presented. A robotic dispensing system was used to divide concentrated aqueous protein solutions into microdroplets 20-mL and to place them onto various solid surfaces in a predetermined manner. Afterward, vacuum drying was applied to reduce the residual moisture of the protein/excipient matrix. Optionally, spray coating of the dry microdroplet patterns was carried out to achieve controlled release. Process parameters were studied and optimized for residual moisture, protein stability, and long-term storage stability.