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: A total of 69 mice , approximately 7 weeks of age , and weighing 21 . 0 to 29 . 1 g were randomly assigned to bupropion HCl 120 mg / kg treatment by intraperitoneal ( IP ) administration in 7 groups ( 9 to 10 animals per group ) .
### Output Text:
A total of 69 mice , approximately 7 weeks of age , and weighing 21 . 0 to 29 . 1 g were randomly assigned to <span class="chemical">bupropion HCl</span> 120 mg / kg treatment by intraperitoneal ( IP ) administration in 7 groups ( 9 to 10 animals per group ) . 