Multi-layered tablets: A comprehensive review on technologies and research

Multilayered tablets combine two or more active pharmaceutical ingredients for an improved therapeutic effect or to achieve a specific drug release profile. In multi-layered tablets two or more active pharmaceutical ingredients can be combined where one layer or one drug may be for immediate release and the other layer of the drug may be for sustained release of drug i.e., one layer is a loading dose and the other layer may be a maintenance dose. Multilayered tablets can help overcome the drug interactions and the disadvantages of non-linearity associated with diffusion-controlled matrix devices, providing an increased surface area and increasing drug release rate with time. This review article discusses different techniques involved in the preparation of multi-layered tablets along with research on multi-layered tablets.