An Overview on Bi-layer Tablets

Bi-layer tablet is a new era for the successful development of controlled release formulation along with various features to provide a way of successful drug delivery system. Bi-layer tablet is suitable for sequential release of two drugs in combination, separate two incompatible substances and also for sustained release tablet in which one layer is immediate release as initial dose and second layer is maintenance dose. Bi-layer tablets has been developed to achieve controlled delivery of different drugs with pre defined release profiles. In the last decade interest in developing a combination of two or more API’s in a single dosage form has increased in the pharmaceutical industry, promoting patient convenience and compliance. Several pharmaceutical companies are presently developing bi-layer tablets, for a variety of reasons patent extension, therapeutic, marketing to name a few. To decrease capital investment, quite often existing but modified tablet presses are used to develop and produce such tablets. This article explains about different techniques of bi-layer tablet and why development and production of quality bi-layer tablets need to be carried out on purpose built tablet presses to conquer common bilayer problems, such as layer separation, insufficient hardness, inaccurate individual layer weight control, cross contamination between the layers, reduced yield etc. There are various applications of the bi-layer tablet consists of monolithic partially coated or multilayered matrices.