I can't ID the coin but I think I can give you some additional direction. The full reverse description looks to Demetrios Basliews (Delta HMHTPIOY BASILEWS). There were Macedonian, Seluecid and Bactrian kings with this name.
The obverse had the head wearing an elepahnt sin headress. I know Alexander the Great issued coins wiht this type of bust. THis may narrow the focus to Macedonian and Seluecid coinage.