Time-dependent changes of oxytocin using (1)H-NMR coupled with multivariate analysis: A new approach for quality evaluation of protein/peptide biologic drugs.

A new method that combines (1)H-NMR and principal component analysis (PCA) was employed to obtain the quality evaluation of biopharmaceuticals, with regard to their quality, consistency, and differences in protein modification patterns. To assess the feasibility of the method, three (1)H-NMR spectra of oxytocin (OXT) were collected every 7 d (at Day 0, 7 and 14), and time-dependent changes in the spectra were found by PCA of the (1)H-NMR signals from 0.5-9.0 ppm, excluding the region around the water signal (4.6-5.0 ppm). Although the three OXT spectra seemed similar by simple visual inspection, time-dependent differences among the three spectra were clearly distinguished by a PCA scores plot. Peak changes indicating both OXT decomposition and the emergence of new OXT decomposition products within the timeframe of the experiment were also observed by a PCA loading plot. The results demonstrate that this method can evaluate the consistency of biopharmaceutical quality.