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: At pH 9 , a higher rate of etodolac release from ED was observed as compared to aqueous buffer of pH 7 . 4 and 80 % human plasma ( pH 7 . 4 ) , following first - order kinetics .
### Output Text:
At pH 9 , a higher rate of <span class="chemical">etodolac</span> release from ED was observed as compared to aqueous buffer of pH 7 . 4 and 80 % human plasma ( pH 7 . 4 ) , following first - order kinetics . 