Diltiazem controlled release formulation

A once-a-day controlled release diltiazem formulation which comprises:

• (a) from 20 to 50% by weight of enteric polymer membrane coated pellets comprising a polymer membrane coated core which comprises a biologically inert core which is coated with a first layer which consists essentially of diltiazem and a polymer binder;
• and a second layer which comprises a membrane comprising polymer enteric coating material selected from the group consisting off shellac, methacrylic acid copolymers and cellulose acetate phthalate;
• and
• (b) from 50% to 80% by weight of delayed pulse polymer membrane coated pellets comprising a polymer membrane coated core which comprises a biologically inert core which is coated with a first layer which consists essentially of diltiazem and a polymer binder and a second layer which comprises a polymer membrane which will maintain its integrity in the varying pH conditions of the gastrointestinal tract but is permeable to diltiazem;
• and
• (c) a unit dose containment system.