RT Journal Article
SR Electronic
T1 A Spectral Method for Color Quantitation of a Protein Drug Solution
JF PDA Journal of Pharmaceutical Science and Technology
JO PDA J Pharm Sci Technol
FD Parenteral Drug Association (PDA)
SP pdajpst.2016.006486
DO 10.5731/pdajpst.2016.006486
A1 Swartz, Trevor E.
A1 Yin, Jian
A1 Patapoff, Thomas W
A1 Horst, Travis
A1 Skieresz, Susan M
A1 Leggett, Gordon
A1 Morgan, Charles J
A1 Rahimi, Kimia
A1 Marhoul, Joseph
A1 Kabakoff, Bruce
YR 2016
UL http://journal.pda.org/content/early/2016/04/13/pdajpst.2016.006486.abstract
AB In the biotechnology industry, a visual method is most commonly utilized for color characterization of liquid drug protein solutions. The color testing method is used for both batch release and on stability testing for quality control. Using that method, an analyst visually determines the color of the sample by choosing the closest matching European Pharmacopeia (Ph. Eur.) reference color solution. The requirement to judge the best match makes it a subjective method. Furthermore, the visual method does not capture data on hue or chroma that would allow for improved product characterization and the ability to detect subtle differences between samples. To overcome these challenges, we describe a quantitative method for color determination that greatly reduces the variability in measuring color and allows for a more precise understanding of color differences. Following color industry standards established by International Commission on Illumination, this method converts a protein solution's visible absorption spectra to L*a*b* color space. Color matching is achieved within the L*a*b* color space, a practice that is already widely used in other industries. The work performed here is to facilitate the adoption and transition for the traditional visual assessment method to a quantitative spectral method. We describe here the algorithm used such that the quantitative spectral method correlates with the currently used visual method. In addition, we provide the L*a*b* values for the Ph. Eur. reference color solutions required for the quantitative method. We have determined these L*a*b* values by gravimetrically preparing and measuring multiple lots of the reference color solutions. We demonstrate that the visual assessment and the quantitative spectral method are comparable using both low and high concentration antibody solutions and solutions with varying turbidity.