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: BNPP did not alter the excretion of APAP or any of its non - deacetylated metabolites nor did BNPP alter excretion of PAP or its metabolites after PAP doses of 150 and 300 mg / kg .
### Output Text:
<span class="chemical">BNPP</span> did not alter the excretion of <span class="chemical">APAP</span> or any of its non - deacetylated metabolites nor did <span class="chemical">BNPP</span> alter excretion of <span class="chemical">PAP</span> or its metabolites after <span class="chemical">PAP</span> doses of 150 and 300 mg / kg . 