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: METHODS : Forty - five hospitalized elderly patients ( > 65 years old ) who required therapy with nonsteroidal antiinflammatory drugs ( NSAID ) were randomly assigned to receive either indomethacin , 150 mg / day ( Group A ) , or indomethacin 150 mg / day plus misoprostol at 0 . 6 mg / day ( Group B ) .
### Output Text:
METHODS : Forty - five hospitalized elderly patients ( > 65 years old ) who required therapy with nonsteroidal antiinflammatory drugs ( NSAID ) were randomly assigned to receive either <span class="chemical">indomethacin</span> , 150 mg / day ( Group A ) , or <span class="chemical">indomethacin</span> 150 mg / day plus <span class="chemical">misoprostol</span> at 0 . 6 mg / day ( Group B ) . 