Oral gastroretentive fixed dose pharmaceutical compositions for the treatment of tuberculosis are provided comprising of rifampicin and isoniazid as the active ingredients. Rifampicin is present in two dosage forms in this formulation. It is present as an immediate release loading dose as well as a gastroretentive maintainence dose. Isoniazid is present in the delayed release form. The two active ingredients, rifampicin and isoniazid are formulated in the dosage form so that they minimaly interact with each other. Moreover, as they are released in separate areas of the intestinal tract, degradation of rifampicin by the presence of isoniazid is considerably reduced, leading to an increase in the bioavailability of rifampicin. The gastroretentive FDC is retained in the human body for a longer duration thus reducing the frequency of dosage.
