Gastroretentive drug formulation and delivery systems and their method of preparation using functionalized calcium carbonate

A method for producing an instantly floating gastroretentive formulation comprising the steps:

• a) providing a functionalized natural or synthetic calcium carbonate comprising mineral (FCC), wherein the functionalized natural or synthetic calcium carbonate is a reaction product of natural or synthetic calcium carbonate with carbon dioxide and one or more acids, wherein the carbon dioxide is formed in situ by the acid treatment and/or is supplied from an external source;
• b) providing at least one pharmaceutically active ingredient;
• c) providing at least one formulating aid;
• d) mixing the compounds provided in steps a), b) and c);
• and
• e) granulating the mixture obtained in step d) by way of melt, dry or wet granulation or roller compaction.