Question about Frontline

I am not sure if i put this in the right place...

I was wondering... since sara and chloe started getting along, they love to bathe each other. I need to put flea meds on both and I was going to try to keep them separated after I put it on, while it is still wet.

But after it dries, if they are grooming each other, is it still poisionous to them. Is it going to make them sick or anything?

It dries very fast. Mine lick each other all the time so I shouldn't worry after a little while.

I can't find the Frontline Plus instructions my vet gave me now, but If I remember right, I think it said on there to keep the cat with the fresh application separate for one and a half hours afterwards.