diff --git a/internal-dev/chebi-ext.owl b/internal-dev/chebi-ext.owl
index aa05aebd..cfa28cb8 100644
--- a/internal-dev/chebi-ext.owl
+++ b/internal-dev/chebi-ext.owl
@@ -1107,8 +1107,6 @@
         <rdfs:subClassOf rdf:resource="http://purl.enanomapper.org/onto/ENM_9000099"/>
         <rdfs:isDefinedBy xml:lang="en"> A titanium dioxide nanoparticle coated with poly(vinylpyrrolidone).</rdfs:isDefinedBy>
         <rdfs:label xml:lang="en">poly(vinylpyrrolidone)-coated TiO2 nanoparticle</rdfs:label>
-        <oboInOwl:hasRelatedSynonym>PVP-coated TiO2 nanoparticle</oboInOwl:hasRelatedSynonym>
-        <oboInOwl:hasRelatedSynonym>TiO2 PVP nanoparticle</oboInOwl:hasRelatedSynonym>
     </owl:Class>
 
 </rdf:RDF>