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: Swiss albino mice prepared with intrajugular catheters were tested in photocell cages after administration of 93 mg / kg ( LD50 ) of cocaine and GNC92H2 infusions ranging from 30 to 190 mg / kg .
### Output Text:
Swiss albino mice prepared with intrajugular catheters were tested in photocell cages after administration of 93 mg / kg ( LD50 ) of <span class="chemical">cocaine</span> and <span class="chemical">GNC92H2</span> infusions ranging from 30 to 190 mg / kg . 