Updates to the Research Institute for Fragrance Materials, Inc. Confirmation of No Induction in Human Test Standard Protocol

<u><b><i></i></b></u> <u><b><i>Background:</i></b></u> At the recommendation of the Expert Panel for Fragrance Safety, the Research Institute for Fragrance Materials, Inc. (RIFM) considered adopting a 48-hour challenge for confirmation of no induction in human (CNIH) studies in order to more closely mimic the patch testing conducted by dermatologists assessing allergic contact dermatitis. <u><b><i>Objectives:</i></b></u> A pilot study was undertaken to ensure that adopting a new protocol would not invalidate the 30+ years of human patch-testing data collected by RIFM. <u><b><i>Methods:</i></b></u> Two protocols were simultaneously tested to determine if a 48-hour challenge patching would result in reactions significantly different from those produced during a 24-hour challenge patching. RIFM tested 19 fragrance materials, including key ingredients in natural complex substances. <u><b><i>Conclusions:</i></b></u> Although patching for 48 hours is more sensitive than patching for 24 hours, during this pilot, no significant differences in sensitization were noted between the two challenge protocols when 2317 subjects were tested with 19 test materials, a vehicle control, and a saline control. Therefore, adopting this new 48-hour challenge patching for RIFM-conducted CNIHs does not invalidate previously published studies conducted according to the 2008 RIFM standard protocol, which utilized a 24-hour patching during the challenge phase.