DUBLIN, Nov 4 (Reuters) - Ireland's High Court ruled on Wednesday against a bid by drugmaker Perrigo, formerly known as Elan, to have a 1.64 billion euro ($1.91 billion) back tax demand quashed.

"I have come to the conclusion that Perrigo has failed to establish any basis to interfere with the assessment issued in respect of the disposal of the Tysabri IP and, accordingly, its claim must be dismissed," the ruling said.

($1 = 0.8570 euros) (Reporting by Conor Humphries; Editing by Edmund Blair)