In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: For PCI , argatroban has not been investigated in hepatically impaired patients ; dose adjustment is unnecessary for adult age , sex , race / ethnicity or obesity , and lesser doses may be adequate with concurrent glycoprotein IIb / IIIa inhibition .
### Output Text:
For PCI , <span class="chemical">argatroban</span> has not been investigated in hepatically impaired patients ; dose adjustment is unnecessary for adult age , sex , race / ethnicity or obesity , and lesser doses may be adequate with concurrent glycoprotein IIb / IIIa inhibition . 