Comparative studies of the sensitization potential of morpholine, 2‐mercaptobenzothiazole and 2 of their derivatives in guinea pigs *

The aim of this study was to determine the sensitization potential of morpholine (M), 4,4'-dithiodimorpholine (DTDM), morpholinyl-mercaptobenzothiazole (MMBT) and 2-mercaptobenzothiazole (MBT) in guinea pigs. 5% and 10% DTDM, MMBT and MBT produced irritation reactions. M up to 10% failed to irritate. Sensitization tests showed that all the guinea pigs treated with DTDM and MMBT were sensitized. Cross-sensitization tests showed that 60% of the DTDM-sensitized animals reacted to challenge with MMBT; 30% of the animals sensitized to DTDM reacted to challenge with M; 80% of the MMBT-sensitized animals reacted to challenge with MBT and 10% to challenge with M; 42% of the MBT-sensitized animals reacted to MMBT. The rank order of sensitization potential in guinea pigs observed from this study is DTDM, MMBT and then MBT. It appears that the disulfide bond, sulfur linkage and the sulfhydryl group may each play a role in the sensitizing capacity of these compounds.