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: However , until this apparent ability of 200 micrograms of misoprostol to prevent the adverse effects of indomethacin on renal function is confirmed with chronic frequent dosing , it would be prudent to avoid nonsteroidal anti - inflammatory therapy in patients with cirrhosis .
### Output Text:
However , until this apparent ability of 200 micrograms of <span class="chemical">misoprostol</span> to prevent the adverse effects of <span class="chemical">indomethacin</span> on renal function is confirmed with chronic frequent dosing , it would be prudent to avoid nonsteroidal anti - inflammatory therapy in patients with cirrhosis . 