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: Group PS , the control group , received normal saline and succinylcholine 1 . 5 mg x kg ( - 1 ) ; Group LS , lidocaine 1 . 5 mg x kg ( - 1 ) and succinylcholine 1 . 5 mg x kg ( - 1 ) ; Group PR , normal saline and rocuronium 0 . 6 mg x kg ( - 1 ) .
### Output Text:
Group PS , the control group , received normal saline and <span class="chemical">succinylcholine</span> 1 . 5 mg x kg ( - 1 ) ; Group LS , <span class="chemical">lidocaine</span> 1 . 5 mg x kg ( - 1 ) and <span class="chemical">succinylcholine</span> 1 . 5 mg x kg ( - 1 ) ; Group PR , normal saline and <span class="chemical">rocuronium</span> 0 . 6 mg x kg ( - 1 ) . 