30498
In the present study , we investigate the influence of glycerol and urea on the permeability of a model drug ( metronidazole , Mz ) across excised pig skin membranes at different hydrating conditions .
 Chemical: glycerol; Chemical: urea; Chemical: metronidazole
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: glycerol, urea, metronidazole 
Answer:
 Chemical: glycerol; Chemical: urea; Chemical: metronidazole