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: METHODS : Rats were anaesthetised with ketamine and were given 0 . 5 mg / kg / min propofol in intralipid ( Group P ) , propofol in medialipid ( Group L ) , or saline ( Group C ) over 20 min .
### Output Text:
METHODS : Rats were anaesthetised with <span class="chemical">ketamine</span> and were given 0 . 5 mg / kg / min <span class="chemical">propofol</span> in intralipid ( Group P ) , <span class="chemical">propofol</span> in medialipid ( Group L ) , or saline ( Group C ) over 20 min . 