Development of the method to identify adducts formed by NAC/NAL and test substances, and oxidation products of NAC in ADRA reaction solutions by high-resolution LC-MS analysis

Abstract

ADRA is an alternative test for skin sensitization using cysteine and lysine derivatives (NAC and NAL) to evaluate the reactivity of chemicals with these reagents. However, since the sensitization potential is decided only by NAC/NAL depletion in this test, it is unclear whether these depletions are truly occurred by reaction with chemicals. We developed the method to identify adducts formed by NAC/NAL and chemicals, and oxidation products of NAC in reaction solutions by LC-MS analysis. We believe this method is useful for differentiating between true and false positive results in ADRA.