| abstract |
Disclosed is a method of optically enriching racemic amlodipine, comprising amlodipine hemitartrate dimethylacetamide monosolvate from a solution comprising amlodipine, dimethylacetamide, and either D- or L-tartaric acid, whereby the amlodipine hemitartrate dimethylacetamide monosolvate precipitate is enriched for one enantiomer of amlodipine. Also disclosed are compositions comprising crystalline S-(-)-amlodipine D-hemitartrate dimethylacetamide or R-(+)-amlodipine L-hemitartrate dimethylacetamide, wherein at least 80% of the amlodipine is S-(-)-amlodipine or R-(+)-amlodipine respectively. |