4302
Here , we have characterized the kappa - selective properties of two ligands , 5 ' - ( 2 - aminomethyl ) naltrindole ( 5 ' - AMN ) and N - ( ( Naltrindol - 5 - yl ) methyl ) pentanimidamide ( 5 ' - MABN ) , to identify whether modifications of the naltrindole side chain produces short - acting kappa - antagonists .
 5 ' - ( 2 - aminomethyl ) naltrindole, 5 ' - AMN, N - ( ( Naltrindol - 5 - yl ) methyl ) pentanimidamide, 5 ' - MABN, naltrindole
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 5 ' - ( 2 - aminomethyl ) naltrindole, 5 ' - AMN, N - ( ( Naltrindol - 5 - yl ) methyl ) pentanimidamide, 5 ' - MABN, naltrindole