5-ALLYLIDENE-10,11-DIHYDRO-5H-DIBENZO[A,D]CYCLOHEPTENE Nortriptyline Impurity H 11-prop-2-enylidene-5,6-dihydrodibenzo[2,1-b:2',1'-f][7]annulene Nortriptyline hydrochloride EP impurity H Nortriptyline EP Impurity H 5H-Dibenzo[a,d]cycloheptene, 10,11-dihydro-5-(2-propen-1-ylidene)- Nortriptyline Impurity 8 (Nortriptyline EP Impurity H) 5-Allylidene-5H-dibenzo[a,d]-10,11-dihydrocycloheptane