(1S,5R,13S,17S)-4-(cyclopropylmethyl)-9-[(1S,13S,17S)-4-(cyclopropylmethyl)-10,17-dihydroxy-14-methylidene-12-oxa-4-azapentacyclo[9.6.1.0^{1,13}.0^{5,17}.0^{7,18}]octadeca-7,9,11(18)-trien-9-yl]-14-me

nalmefene impurity ; (5?)-(5'?)-17,17'-bis(cyclopropylmethyl)-4,5:4',5'-diepoxy-6,6'-bis(methylene)-[2,2'-bimorphinan]-3,3',14,14'-tetrol ; 2,2'-bisnalmefene (nalmefene impurity) ; 2,2'-bisnalmefene ; (5a)-(5'a)-17,17'-bis(cyclopropylmethyl)-4,5:4',5'-diepoxy-6,6'-bis(methylene)-[2,2'-bimorphinan]-3,3',14,14'-tetrol ; nalmefene related substance ; nalmefene hydrochloride dimer ; 2,2'-bis(6-deoxo-6-methylenenaltrexone) ; [2,2'-bimorphinan]-3,3',14,14'-tetrol,17,17'-bis(cyclopropylmethyl)-4,5:4',5'-diepoxy-6,6'-bis(methylene)-, (5a)-(5'a)- (9ci) ; 2,2'-bis(6-deoxo-6-methylenenaltrexone ; 2,2'-bisnalmefene (nalmefene impurity) (>85%)