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: Patients with essential hypertension ( mean sitting diastolic BP [ MSDBP ] , > or = 95 mm Hg and < 110 mm Hg ) were randomized to 1 of 8 treatment groups : VAL 160 or 320 mg ; HCTZ 12 . 5 or 25 mg ; VAL / HCTZ 160 / 12 . 5 , 320 / 12 . 5 , or 320 / 25 mg ; or placebo .
### Output Text:
Patients with essential hypertension ( mean sitting diastolic BP [ MSDBP ] , > or = 95 mm Hg and < 110 mm Hg ) were randomized to 1 of 8 treatment groups : <span class="chemical">VAL</span> 160 or 320 mg ; <span class="chemical">HCTZ</span> 12 . 5 or 25 mg ; <span class="chemical">VAL</span> / <span class="chemical">HCTZ</span> 160 / 12 . 5 , 320 / 12 . 5 , or 320 / 25 mg ; or placebo . 