Cocrystals of Pentoxifylline: In Silico and Experimental Screening

Abstract

To obtain new crystal forms with altered physicochemical properties and to get insight into the driving forces guiding cocrystallization, we performed experimental and in silico screening of pentoxifylline with 11 pharmaceutically acceptable organic acids. Neat grinding, liquid-assisted grinding, and slow solvent evaporation were used to obtain cocrystals of pentoxifylline. The free energy of experimental and hypothetical crystal structures have been calculated using the FlexCryst program. Three cocrystals of pentoxifylline with aspirin, salicylic acid, and benzoic acid in a 1:1 molar ratio have been obtained and characterized by physical methods. The experimental and in silico results were found to match very well. Strong correlation between melting points of pentoxifylline cocrystals and coformers has been detected. A significant decrease in solubility of pentoxifylline cocrystals as compared to pure pentoxifylline was observed.