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: The time - course curve of creatinine clearance dropped and showed significant difference ( P less than 0 . 01 ) from that of each control group , such as , AMNS alone , PS alone or saline injected .
### Output Text:
The time - course curve of <span class="chemical">creatinine</span> clearance dropped and showed significant difference ( P less than 0 . 01 ) from that of each control group , such as , <span class="chemical">AMNS</span> alone , <span class="chemical">PS</span> alone or saline injected . 