| abstract |
The subject invention provides a varenicline composition comprising varenicline, or a pharmaceutically acceptable salt thereof, and an amount of a compound selected from one or more of several mononitro, monoamine, mixed aminonitre, diamino or dinitro intermediates, and the concentration of said compound is greater than 0 ppm and not greater than approximately 500 ppm, not greater than approximately 100 ppm or not greater than approximately 10 ppm. Methods for synthesizing and using such varenicline compositions are also provided. |