You can try a gentle leader and get out a peanut butter jar....and let one person hold the jar while he licks it. Then he should be distracted enough for you to get that medicine in his ear. The peanut butter helps to make.... an unpleasant thing seem a little better.
The gentle leader makes it a little harder for him to bite, but he can still eat!
If he is'nt fond of Peanut butter use cheese whiz in the jar.
Or you can just use the muzzle if you are unsure about him biting you. he can't bite at all with a muzzle. Just remmeber to give him a good treat("HIS FARVORITE") before and after, so if you have to treat his ears often.....then the expierence won't seem sooooooo unpleasant!!
Hope this helps you some.
~Norma