pdc-apb pdc-apb pdc-apb, or 3-pentadecyl-1,2-phenylene bis(4-(4-aminophenyl)butanoate), is a drug candidate under evaluation to determine if it might protect against contact dermatitis caused by urishiol from poison ivy, poison oak, and poison sumac. pdc-apbclinical dataother names3-pentadecyl-1,2-phenylene bis(4-(4-aminophenyl)butanoate; benzenebutanoic acid, 4-amino-, 1,1'-(3-pentadecyl-1,2-phenylene) esteridentifiers iupac name -3-pentadecylphenyl] 4-(4-aminophenyl)butanoate cas number2016046-95-8pubchem cid89683272uniilx6rqk5701chemical and physical dataformulac41h58n2o4molar mass642.925 g·mol−13d model (jsmol)interactive image smiles cccccccccccccccc1=c(c(=cc=c1)oc(=o)cccc2=cc=c(c=c2)n)oc(=o)cccc3=cc=c(c=c3)n inchi inchi=1s/c41h58n2o4/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-20-35-21-17-22-38(46-39(44)23-15-18-33-25-29-36(42)30-26-33)41(35)47-40(45)24-16-19-34-27-31-37(43)32-28-34/h17,21-22,25-32h,2-16,18-20,23-24,42-43h2,1h3key:vlrzirygluvggu-uhfffaoysa-n history the compound is one of a class of compounds developed through university of mississippi research by mahmoud elsohly, waseem gul, and mohammad khalid ashfaq. work on the compound is ongoing under hapten sciences, who licensed the university's research in 2010. evaluation as a drug candidate the compound has been evaluated in two phase i clinical trials, and a third phase i randomized controlled trial, with a secondary objective of evaluating the effect of treatment on urishiol sensitivity, is due to be completed in december 2022.