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: Importantly , the local irritation of ACC - 9653 was markedly less than phenytoin sodium following i . m . administration . ( ABSTRACT TRUNCATED AT 250 WORDS )
### Output Text:
Importantly , the local irritation of <span class="chemical">ACC - 9653</span> was markedly less than <span class="chemical">phenytoin sodium</span> following i . m . administration . ( ABSTRACT TRUNCATED AT 250 WORDS ) 