Not really. Red Lipstick was just copying and pasting lyrics onto a 5 year old beat.
"You Da One" flopped and the dubstep breakdown wasn't even hot.
G4L and Wait Your Turn were never released.
"Hold It Against Me" wen't #1 and was the first TRUE dubstep infused song on Top 40 radio. TTWE #3....and had lots of dubstep influences, then the remix compounded onto that inspiring future dubstep-ish songs like "Good Feeling", "Last Friday Night (remix)", etc...
So yes, both have tried to infuse dubstep into their music...but only Britney "really stood out." - and infused dubstep "in a great way."