The standard for biosimilarity is the demonstration of analytical and functional similarity of a biosimilar product to the reference product, with no clinically meaningful differences between the two. Our objective is to develop a platform that allows for reliable characterization and evaluation of comparability of biosimilar drug products. A key challenge when performing these activities is that the excipients in the formulation interfere with the typical set of analytical and functional tools that are otherwise routinely used for the characterization and comparability of drug substances. As a result, biosimilar manufacturers resort to a variety of approaches to isolate the biotherapeutic protein from the drug product formulation. However, this introduces an uncertainty brought about by the impact of this isolation on protein stability and function. We will first identify the root of challenges that impact the characterization of biotherapeutic drug products. Armed with this understanding, this project aims at creating an analytical platform that allows us to perform reliable analytical and functional characterization and evaluation of the comparability of biosimilar drug products. Comprehensive characterization of excipients, alone and in compositions simulating biosimilar products will be carried out. In addition, analytical and functional characterization of biosimilars and the reference product will be conducted. Finally, the container-closure systems will be evaluated.