I recently saw that some brands of Telmisartan, Amlodipine and Hydrochlorothiazide tablets are bilayered and some are not?
On Googling I found this
Bilayered tablet technology separates two incompatible substances in which one layer is immediate release as a loading dose, and the second layer is controlled/sustained release as a maintenance dose. Two incompatible drugs can also be formulated into a bilayer tablet by adding an inert intermediate layer.
Also this where it says that both telmisartan and amlodipine are instantly released. But then it uses two different methods for it. Why?
A bilayer tablet comprises a first layer formulated for instant release of the angiotensin II receptor antagonist telmisartan from a dissolving tablet matrix and a second layer formulated for instant release of the calcium channel blocker amlodipine from a disintegrating or eroding tablet matrix.
But none of the above mentioned drugs are incompatible with each other. Moreover all of them are often used once per day.
So I don't see the rationale of using a bilayer for incompatibility or controlled release.
Why is this being done by some brands?
Non Bilayered tablets