Analytical Aspects of Biopharmaceuticals and their Study by Mass Spectrometry

The use of biopharmaceuticals has increased significantly over the past two decades. Many original biological drugs were registered, that are mainly protein-based pruducts, produced by a biotechological method. Since biologics are heterogeneous mixtures of complex macromolecules, their characterization is an extremely complicated task. Their analysis is done by an array of chromatographic, electrophoretic and spectroscopic techniques. These methods are suitable for the study of the primary and higher order structure, stability, interactions and multimerization of proteins. Due to its sensitivity, selectivity and high throughput, mass spectrometry coupled to separation techniques is a widely used technique for the study of biological drugs to determine the molecular mass and amino acid sequence of the protein, the heterogeneity of the sample and its post-translational modifications. Additionally, mass spectrometry allows qualitative analysis of these products as well. In the present article, we review biological drugs, biosimilars and their methods for their analysis, with particular emphasis on the application of mass spectrometry.