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: RESULTS : The average time from intravenous administration of ketamine to manipulation of the fracture or dislocation was one minute and thirty - six seconds ( range , twenty seconds to five minutes ) , and the average time from intramuscular administration to manipulation was four minutes and forty - two seconds ( range , sixty seconds to fifteen minutes ) .
### Output Text:
RESULTS : The average time from intravenous administration of <span class="chemical">ketamine</span> to manipulation of the fracture or dislocation was one minute and thirty - six seconds ( range , twenty seconds to five minutes ) , and the average time from intramuscular administration to manipulation was four minutes and forty - two seconds ( range , sixty seconds to fifteen minutes ) . 