Expanding the Pool of Multicomponent Crystal Forms of the Antibiotic 4-Aminosalicylic Acid: The Influence of Crystallization Conditions

Finding new multicomponent crystal forms of commercially available pharmaceuticals is important, as they represent a straightforward way to drastically influence the solid-state properties of a drug. The antibiotic 4-aminosalicylic acid (ASA) is known to exist in several multicomponent crystal forms, and in this work we expand the world of ASA cocrystals and salts by reporting new crystalline forms comprising diazabicyclo[2.2.2]octane (DABCO), and caffeine. All species were characterized by X-ray single crystal, powder diffraction, and thermal behavior. This study contributes to the rationalization of preferred functional groups for the synthesis of 4-aminosalicylic acid new multicomponent crystal forms and highlights the relevance of the reaction conditions in the achievement of those forms.