Abstract

Novel glycopyrronium fatty acid salts have been developed. Bi-phasic reaction conditions enable the desired counterion exchange reactions between glycopyrronium bromide and fatty acid salts of alkali metals and alkaline earth metals in methods to form glycopyrronium fatty acid salts. In preferred embodiments, an excess of the free fatty acid in the reaction mixture stabilizes the glycopyrronium fatty acid salt and reduces the formation of the impurity, Acid A. In some preferred embodiments, between 0.2 and 1.2 molar equivalent of excess free fatty acid is added to the reaction mixture. In another embodiment, approximately 1.2 molar equivalent of excess free fatty acid is added to the reaction mixture.