Occurrence of pharmaceutically acceptable anions and cations in the Cambridge Structural Database.

The occurrence of a number of pharmaceutically acceptable counterions in the Cambridge Structural Database (CSD) has been investigated. The results have been compared to the occurrence of the same counterions in a list of known pharmaceutical salts. Chloride salts are by far the highest occurring in both groups. The occurrence of hydrates in the structures of salts of pharmaceutically acceptable counterions in the CSD has also been investigated. It was found that salts of these counterions show an increased tendency to hydrate when compared to the database average. The CSD was also searched for co-crystals of the list of pharmaceutically acceptable acids and bases corresponding to the list of counterions used for the salt investigation.