Heteronuclear NMR provides an accurate assessment of therapeutic insulin's quality.

New generations of drugs are using more and more often therapeutic proteins as the active ingredient, prompting the regulation agencies to adapt their analytical methods. Fast and unambiguous information on the secondary, tertiary and quaternary structure of the protein should be provided to assess the quality of these biodrugs. Recent developments of heteronuclear NMR methods, enabling their use on pharmaceutical formulated unlabeled proteins, provide an efficient way to perform such analysis, a feature that is illustrated here using various commercial formulations of insulins.