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: In addition , tacrine - loaded nanoparticles administration induced damage of neuronal cells in CA1 field of the hippocampus in all treated animals , while the saline solution of tacrine only in 60 % of animals .
### Output Text:
In addition , <span class="chemical">tacrine</span> - loaded nanoparticles administration induced damage of neuronal cells in CA1 field of the hippocampus in all treated animals , while the saline solution of <span class="chemical">tacrine</span> only in 60 % of animals . 