esterom esterom esterom is an investigational drug being studied as a topical analgesic. chemically, it is a mixture of compounds derived from the esterification of cocaine in propylene glycol. while the major component is benzoylecgonine, the analgesic activity is likely to due to hydroxypropyl benzoylecgonine, the only component that penetrates the skin. esterombenzoylecgonine (top), the major component, and hydroxypropyl benzoylecgonine (bottom), the most active componentclinical datatrade namesesteromidentifiersdrugbankdb01515