Notes: Arbaprostil (15(R)-15-methyl prostaglandin E2) is a synthetic prostaglandin E2 (PGE2) analog developed for its cytoprotective activity.{2958} 15(R)-15-methyl Prostaglandin A2 (15(R)-15-methyl PGA2) is one of several impurities which are possible in the production of commercial lots of bulk arbaprostil.{2016} The pharmacology and EP receptor binding affinity for 15(R)-15-methyl PGA2 has not been published.