Water proton NMR detection of amide hydrolysis and diglycine dimerization

Revisiting the influence of pH on 1JCαH and chemical shifts of glycine and alanine short oligopeptides

The pH dependence of several NMR parameters of glycine and alanine short oligopeptides has been reported previously in different studies. Here we have thoroughly examined, summarized and demonstrated the dependences of 1H, 13C and 15N chemical shifts and protonation states of amino acids using two-dimensional NMR experiments. Nevertheless, 1JCαH one bond spin-spin coupling constants are more informative and convenient for determination of the position and protonation state of glycine and alanine residue in the oligopeptide chain. In particular, for various oligopeptides (up to six residues), it was shown that the pH dependence of 1JCαH of N-terminal glycine and alanine residues is larger than that of C-terminal groups, and in backbone residues, it is not influenced by pH and only slightly depends on the position of the amino acid residue in the chain.

Assessing Antigen-Adjuvant Complex Stability Against Physical Stresses By wNMR

This study applies an emerging analytical technology, wNMR (water proton nuclear magnetic resonance), to assess the stability of aluminum adjuvants and antigen-adjuvant complexes against physical stresses, including gravitation, flow and freeze/thaw. Results from wNMR are verified by conventional analytical technologies, including static light scattering and microfluidic imaging. The results show that wNMR can quickly and noninvasively determine whether an aluminum adjuvant or antigen-adjuvant complex sample has been altered by physical stresses.

Inspecting Insulin Products Using Water Proton NMR. I. Noninvasive vs Invasive Inspection

BACKGROUND

There is a clear need to transition from batch-level to vial/syringe/pen-level quality control of biologic drugs, such as insulin. This could be achieved only by noninvasive and quantitative inspection technologies that maintain the integrity of the drug product.

METHODS

Four insulin products for patient self-injection presented as prefilled pens have been noninvasively and quantitatively inspected using the water proton NMR technology. The inspection output is the water proton relaxation rate R₂(¹H₂O), a continuous numerical variable rather than binary pass/fail.

RESULTS

Ten pens of each product were inspected. R₂(¹H₂O) displays insignificant variation among the 10 pens of each product, suggesting good insulin content uniformity in the inspected pens. It is also shown that transferring the insulin solution out of and then back into the insulin pen caused significant change in R₂(¹H₂O), presumably due to exposure to O₂ in air.

CONCLUSIONS

Water proton NMR can noninvasively and quantitatively inspect insulin pens. wNMR can confirm product content uniformity, but not absolute content. Its sensitivity to sample transferring provides a way to detect drug product tampering. This opens the possibility of inspecting every pen/vial/syringe by manufacturers and end-users.

Comprehensive Assessment of Protein and Excipient Stability in Biopharmaceutical Formulations Using 1H NMR Spectroscopy

Biopharmaceutical proteins are important drug therapies in the treatment of a range of diseases. Proteins, such as antibodies (Abs) and peptides, are prone to chemical and physical degradation, particularly at the high concentrations currently sought for subcutaneous injections, and so formulation conditions, including buffers and excipients, must be optimized to minimize such instabilities. Therefore, both the protein and small molecule content of biopharmaceutical formulations and their stability are critical to a treatment's success. However, assessing all aspects of protein and small molecule stability currently requires a large number of analytical techniques, most of which involve sample dilution or other manipulations which may themselves distort sample behavior. Here, we demonstrate the application of 1H nuclear magnetic resonance (NMR) spectroscopy to study both protein and small molecule content and stability in situ in high-concentration (100 mg/mL) Ab formulations. We show that protein degradation (aggregation or fragmentation) can be detected as changes in 1D 1H NMR signal intensity, while apparent relaxation rates are specifically sensitive to Ab fragmentation. Simultaneously, relaxation-filtered spectra reveal the presence and degradation of small molecule components such as excipients, as well as changes in general solution properties, such as pH. 1H NMR spectroscopy can thus provide a holistic overview of biopharmaceutical formulation content and stability, providing a preliminary characterization of degradation and acting as a triaging step to guide further analytical techniques.

Nondestructive Quantitative Inspection of Drug Products Using Benchtop NMR Relaxometry-the Case of NovoMix® 30

Batch-level inference-based quality control is the standard practice for drug products. However, rare drug product defects may be missed by batch-level statistical sampling, where a subset of vials in a batch is tested quantitatively but destructively. In 2013, a suspension insulin product, NovoLog® Mix 70/30 was recalled due to a manufacturing error, which resulted in insulin strength deviations up to 50% from the labeled value. This study analyzed currently marketed FlexPen® devices by the water proton transverse relaxation rate using a benchtop nuclear magnetic resonance relaxometer. The water proton transverse relaxation rate was found to be sensitive to detecting concentration changes of the FlexPen® product. These findings support the development of vial-level verification-based quality control for drug products where every vial in a batch is inspected quantitatively but nondestructively.