US Patent 8252331 Osmotic device containing amantadine and an osmotic salt

The osmotic devices of the present invention contain a unitary core comprising a salt of amantadine and an osmotic salt, wherein the two salts have an ion in common. The release rate of the amantadine is modified from a first order release profile to a zero order, pseudo-zero order or sigmoidal release profile by increasing the amount of the osmotic salt in the core of the device. The osmotic device includes a semipermeable membrane having a controlled porosity that can be adapted as needed to cooperate with the osmotic salt in providing a predetermined drug release profile. The osmotic salt need not be coated and it is in admixture with the amantadine salt.