Determination of recombinant protein in animal cell culture supernatant by near-infrared spectroscopy.

A method is described for the measurement of recombinant protein in animal cell culture supernatants with near-infrared (NIR) absorbance spectroscopy. Human antithrombin III is determined in CHO (Chinese hamster ovary)-T1 medium, both fresh and taken from CHO cell culture. NIR spectra are collected over the frequency range of 1000-2500 nm. A multivariate calibration model is generated by correlating spectral features with concentration values using partial least-squares regression. Separate test sets are used to evaluate the computed model. Protein measurement is established over the range 0.1-5 micrograms/mL with a standard error of prediction of less than 0.5 microgram/mL. This result underlines the analytical applicability of NIR spectroscopy for animal cell culture process monitoring.