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: Ketamine hydrochloride was administered intravenously ( at a dose of two milligrams per kilogram of body weight ) in ninety - nine of the patients and intramuscularly ( at a dose of four milligrams per kilogram of body weight ) in the other fifteen .
### Output Text:
<span class="chemical">Ketamine hydrochloride</span> was administered intravenously ( at a dose of two milligrams per kilogram of body weight ) in ninety - nine of the patients and intramuscularly ( at a dose of four milligrams per kilogram of body weight ) in the other fifteen . 