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: The toxic effects of tacrine - loaded poly - L - lactid acid nanoparticles ( 5mg / kg ) , a saline solution of tacrine ( 5mg / kg ) and an empty colloidal nanoparticle suspension were compared following i . p . administration in LiCl - pre - treated Wistar rats .
### Output Text:
The toxic effects of <span class="chemical">tacrine</span> - loaded <span class="chemical">poly - L - lactid acid</span> nanoparticles ( 5mg / kg ) , a saline solution of <span class="chemical">tacrine</span> ( 5mg / kg ) and an empty colloidal nanoparticle suspension were compared following i . p . administration in <span class="chemical">LiCl</span> - pre - treated Wistar rats . 