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: Penicillamine - related lichenoid dermatitis and utility of zinc acetate in a Wilson disease patient with hepatic presentation , anxiety and SPECT abnormalities .
### Output Text:
<span class="chemical">Penicillamine</span> - related lichenoid dermatitis and utility of <span class="chemical">zinc acetate</span> in a Wilson disease patient with hepatic presentation , anxiety and SPECT abnormalities . 