Manufacturers of monoclonal antibodies (mAbs) and other biologics have a new way to monitor changes in higher order structures of their products. This method lets them see alterations in real time and, potentially, to inspect every vial before it is released.

It is based on the direct correlation of the changes in water relaxation measured using time domain nuclear magnetic resonance (wNMR). Any changes can be correlated with stability, heterogeneity, and binding affinities of higher order structures identified by high-resolution 2D NMR spectral analysis and other orthogonal analytical methods.

This insight came through a study of forced degradation by chemical oxidation in which correlations were made among various analytical measurements of perturbations in the critical quality attribute of higher order structures. The key questions were “how much change in the 2D NMR spectral fingerprint is expected before a functional change occurs that may detrimentally affect the safety and efficacy of a given mAb therapeutic,” and “would real-time wNMR measurements correlate with the same underlying higher order structure changes,” Robert G. Brinson, PhD, research chemist at the National Institute of Standards and Technology (NIST) and principal investigator for this study, tells GEN.

Portable and compact

“While wNMR is a low-resolution technique, the instrument is portable and compact and the measurement takes less than one minute,” Brinson says. “It not only has the ability for [real-time, non-invasive] reaction monitoring, but also the potential to quantitatively and non-invasively inspect every vial before release.” Therefore, “wNMR could become as common as HPLC.”

The project used reference material NISTmAb for an IgG1 therapeutic class and measured higher order structure perturbations arising from chemical oxidation using 2D-NMR, wNMR and other analytical techniques. “Results showed clear linear correlations between wNMR and 2D-NMR measurements and observed changes in stability and functional response,” Brinson says.

Before this technique can be applied to commercial manufacturing, “more statistical and chemometric work is needed to develop a robust analysis protocol, including linking spectral perturbations to a bioassay.” He also notes that a published interlaboratory study to standardize operational protocols and gain stakeholder consensus for pharmaceutical applications is needed for wNMR. Such a study was performed for 2D-NMR in 2019.

Three of the researchers on this research are also involved in projects with the FDA to further advance and harmonize NMR methods for application to biopharmaceuticals.

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