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: Two of the 64 patients in the iodixanol group ( 3 percent ) had an increase in the creatinine concentration of 0 . 5 mg per deciliter or more , as compared with 17 of the 65 patients in the iohexol group ( 26 percent ) ( P = 0 . 002 ; odds ratio for such an increase in the iodixanol group , 0 . 09 [ 95 percent confidence interval , 0 . 02 to 0 . 41 ] ) .
### Output Text:
Two of the 64 patients in the <span class="chemical">iodixanol</span> group ( 3 percent ) had an increase in the <span class="chemical">creatinine</span> concentration of 0 . 5 mg per deciliter or more , as compared with 17 of the 65 patients in the <span class="chemical">iohexol</span> group ( 26 percent ) ( P = 0 . 002 ; odds ratio for such an increase in the <span class="chemical">iodixanol</span> group , 0 . 09 [ 95 percent confidence interval , 0 . 02 to 0 . 41 ] ) . 