Bilayer tablet is a two layered tablet, where first layer releases the drug via immediate release and second layer releases the drug via controlled release.
Bilayer technology is a newer technology for the development of controlled release formulation in pharmaceutical industry. Where a combination of two or more active pharmaceutical ingredients is developed in a single dosage form. This can also be used to formulate dosage form containing two incompatible APIs.
Example of Bilayer Tablets
- Panadol Osteo (Paracetamol) Tablet
- Amaryl M (Glimepiride and Metformin) Tablet
- Amlodipine, Telmisartan AND Hydrochlorothiazide Tablet
- Mucinex (Guaifenesin) tablet
Manufacturing Procedure (Compression Process)
Two layer of granules prepare separately and keep in two different hopper of the compression machine. Where one layer is compressed firstly with low compression force, then second layer is compressed with optimal binding between the layers.
Criticality of Bi-layer Tablet Formulation
The ratio of both layer of tablet to be comparable (50/50 or 60/40) for bilayer tablet to minimize the weight variation and ensure the content uniformity.
The hardness of the firstly pressed layer to be kept in lower side (2-3) kp for better binding with secondly pressed layer. Because, correct bonding is only obtained when the first layer is compressed at a low compression force so that this layer can still interact with the second layer during final compression.
Advantages of Bi-layer Tablets
- Increase productivity
- Immediate release and modified release mechanism in a single tablet
- Separate incompatible components
- Maintain physical and chemical stability
- Reduce number of dose
- Novel technology
Disadvantages of Bi-layer Tablets
- Chance to layer separation
- Risk to fail content uniformity
- Low output
- Cross contamination between the layers
Bi-layer tablet is a novel technology to overcome the limitation of the single layered tablet. There is various application of the bi-layer tablet it consist 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 immediate release (initial dose) and second layer as controlled release (maintenance dose).
Precaution: This tablet must be swallowed whole and not crushed or chewed.
