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 analogs tested were : 11 - ketopregnenolone sulphate ( an agent that is inactive at GABA ( A ) Rs and NMDARs ) , epipregnanolone ( [ 3beta - hydroxy - 5beta - pregnan - 20 - one ] sulphate , an inhibitor of both GABA ( A ) Rs and NMDARs ) , and a newly synthesized ( - ) PREGS enantiomer ( which is identical to PREGS in effects on GABA ( A ) Rs and NMDARs ) .
### Output Text:
The analogs tested were : <span class="chemical">11 - ketopregnenolone sulphate</span> ( an agent that is inactive at <span class="chemical">GABA</span> ( A ) Rs and NMDARs ) , <span class="chemical">epipregnanolone ( [ 3beta - hydroxy - 5beta - pregnan - 20 - one ] sulphate</span> , an inhibitor of both <span class="chemical">GABA</span> ( A ) Rs and NMDARs ) , and a newly synthesized ( - ) <span class="chemical">PREGS</span> enantiomer ( which is identical to <span class="chemical">PREGS</span> in effects on <span class="chemical">GABA</span> ( A ) Rs and NMDARs ) . 