I'm not aware of an effective dissolution inhibitor for WO3 at high pH (if this is what you're asking), even though at one point I spent some time looking for one.
It is conceivable that, if the high pH is achieved through addition of an alkaline-earth (Ca/Sr/Ba) hydroxide, the tungstate formed will deposit as a film on the surface of the WO3 particle, since alkaline-earth tungstates have very low solubilities. But then your particles will not be WO3, strictly speaking.