An initial bid of £400,000 rising to £500,000 for the 26-year-old was turned down by the Seasiders. The Rams returned with an improved offer only to have that thrown out.
It is thought Blackpool want between £700,000 and £1million for their captain, who has a year remaining on his contract at Bloomfield Road.
"He remains one of our top targets and we are still pursuing it at the moment," Rams boss Nigel Clough told the Derby Telegraph.
Meanwhile, Derby also remain keen on signing Crewe right-back John Brayford. The Rams have had one offer for the 21-year-old, who played under Clough at Burton, rejected by the League Two club.
Clough insists the situation is 'ongoing', and added: "We put a bid in a while back and Crewe's valuation was way above ours. It always seems to be the way, but a bit of toing and froing and I think eventually we will get an agreement suitable to all parties."