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: Picloxydine irrigations appeared to have a lower incidence of erosive cystitis but further studies would have to be performed before it could be recommended for use in urological procedures .
### Output Text:
<span class="chemical">Picloxydine</span> irrigations appeared to have a lower incidence of erosive cystitis but further studies would have to be performed before it could be recommended for use in urological procedures . 