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: Pain intensity on a 0 to 10 numerical scale ; nausea and vomiting , drowsiness , confusion , and dry mouth , using a scale from 0 to 3 ( not at all , slight , a lot , awful ) ; Mini - Mental State Examination ( MMSE ) ( 0 - 30 ) ; and arterial pressure were recorded before administration of drugs ( T0 ) and after 30 minutes ( T30 ) , 60 minutes ( T60 ) , 120 minutes ( T120 ) , and 180 minutes ( T180 ) .
### Output Text:
Pain intensity on a 0 to 10 numerical scale ; nausea and vomiting , drowsiness , confusion , and dry mouth , using a scale from 0 to 3 ( not at all , slight , a lot , awful ) ; Mini - Mental State Examination ( MMSE ) ( 0 - 30 ) ; and arterial pressure were recorded before administration of drugs ( T0 ) and after 30 minutes ( T30 ) , 60 minutes ( T60 ) , 120 minutes ( T120 ) , and 180 minutes ( T180 ) . 