22073
Characterization studies of the prepared liposomal formulations were performed by dynamic light scattering , extrusion , and ( 1 ) H and ( 31 ) P - nuclear magnetic resonance ( NMR ) spectroscopy .
 Chemical: ( 1 ) H; Chemical: ( 31 ) P
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: ( 1 ) H, ( 31 ) P 
Answer:
 Chemical: ( 1 ) H; Chemical: ( 31 ) P