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: We report on a patient with leftward and upward deviations of gaze during the peak effect of levodopa , and hypothesize that a severe dopaminergic denervation in the caudate nucleus is needed for the appearance of these levodopa - induce ocular dyskinesias .
### Output Text:
We report on a patient with leftward and upward deviations of gaze during the peak effect of <span class="chemical">levodopa</span> , and hypothesize that a severe dopaminergic denervation in the caudate nucleus is needed for the appearance of these <span class="chemical">levodopa</span> - induce ocular dyskinesias . 