The present invention relates to a pharmaceutical composition in a solid unit
dosage form for oral administration in a human or lower animal comprising: a. a
safe and effective amount of a therapeutically active agent; b. an inner coating
layer selected from the group consisting of poly(methacrylic acid, methyl methacrylate)
1:2, poly(methacrylic acid, methyl methacrylate) 1:1, and mixtures thereof; and
c. an outer coating layer comprising an enteric polymer or film coating material;
wherein the inner coating layer is not the same as the outer coating layer; wherein
if the inner coating layer is poly(methacrylic acid, methyl methacrylate) 1:1 then
the outer coating layer is not poly(methacrylic acid, methyl methacrylate) 1:2
or is not a mixture of poly(methacrylic acid, methyl methacrylate) 1:1 and poly(methacrylic
acid, methyl methacrylate) 1:2; and wherein the inner coating layer and the outer
coating layer do not contain any therapeutically active agent. This invention further
relates to a method of maintaining the desired site of delivery of a therapeutic
agent in the gastrointestinal tract by administering the above compositions to
a human or lower animal.
