| abstract |
The invention relates to a process, which comprises assaying amlodipine, a pharmaceutically acceptable salt thereof, or a composition containing the same for the presence of at least one of specific compounds 1(b)-1(f), to a process of testing the purity of phthalimidoamlodipine, which comprises assaying phthalimidoamlodipine, a pharmaceutically acceptable salt thereof, or a composition containing the same for the presence of at least one of the specific compounds 2b-2e, and to a process of producing amlodipine, which comprises the steps of:(a) assaying a sample from a batch of phthalimidoamlodipine for at least one phthalimidoamlodipine impurity selected from the group consisting of the compounds 2b-2e:(b) determining whether said at least one phthalimidoamlodipine impurity is contained in said sample below a predetermined limit, and, if below said predetermined limit;(c) subjecting said phthalimidoamlodipine batch to deprotection to form a batch of amlodipine. |