How to prevent degradation of dihydropyridine compounds

Dihydropyridine compounds such as amlodipine by the addition of water, production of directly or unstable after forming hydrates, the decomposition of the pyridine material is promoted, pharmaceutical compositions containing dihydropyridine compounds as a method, the dihydropyridine compounds is limited to the method without addition of water, such as a method of adding powder, by varying the granulation conditions, be easily adjusted moldability and hardness of the tablets, and the like Kuzurefutokoro property It can be, and was not suitable for easy wet granulation method to ensure the uniformity of the ingredients. In the present invention, when the wet process the dihydropyridine compounds, prevent degradation of in the coexistence of the cellulose polymer that are replaced by a methyl group, formation and / or dihydropyridine compound hydrate dihydropyridine compounds to.