Chris Butler, PhD, Senior Principal Analytical Scientist, Perrigo Nutritionals
JMP was used to develop an enzyme-linked immunosorbent assay (ELISA) using a Quality by Design approach. Intact milk proteins, including casein, cause allergic reactions in infants with confirmed milk allergy. We developed a hypoallergenic milk-based infant formula (HIF) using extensively hydrolyzed casein putatively devoid of relevant antigenic determinants. Since the aim of such a formula is to prevent exposure to protein antigens, we also developed an analytical method capable of detecting casein antigenic determinants in raw materials and HIF finished products accurately and precisely at or below 20 parts-per-million, i.e., 20 µg casein per gram of HIF. The Fit Y by X platform was used to discern models of concentration-response data, predict optimal sample extraction concentration, and investigate assay suitability failures. A classical mixture design was used to assess robustness of a six-component extraction buffer, and a separate custom design was used to assess robustness with respect to four sample preparation parameters.