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: Results of a comparative , phase III , 12 - week , multicenter , prospective , randomized , double - blind assessment of the efficacy and tolerability of a fixed - dose combination of telmisartan and amlodipine versus amlodipine monotherapy in Indian adults with stage II hypertension .
### Output Text:
Results of a comparative , phase III , 12 - week , multicenter , prospective , randomized , double - blind assessment of the efficacy and tolerability of a fixed - dose combination of <span class="chemical">telmisartan</span> and <span class="chemical">amlodipine</span> versus <span class="chemical">amlodipine</span> monotherapy in Indian adults with stage II hypertension . 