Ionic liquids as pharmaceutical salts: A historical perspective

Design and synthesis of pharmaceutically acceptable salts is one of the prime aspect of drag development. An estimated half of all drags used in medicine are administered as salts. The salt formation of drug candidates has been recognized as an essential preformulation task. Salt formation of APIs can improve their aqueous solubility, industrial processing, safety aspects and sometimes biological properties. These properties can be further enhanced by changing counterion of the active component. Though there is no concerned effort of finding applications of ionic liquids in the pharmaceutical arena in recent years, a detailed survey of the literature shows that pharmaceutical salts having properties now termed as 'ionic liquids' have existed for a long time. In this chapter a historical overview of 'ionic liquid like pharmaceutical salts', their importance and application in drag development has been described.