• Combined virtual/experimental multicomponent solid forms screening of sildenafil: new salts, cocrystals, and hybrid salt-cocrystals

      Barbas, R.; Font-Bardia, M.; Paradkar, Anant R.; Hunter, C.A.; Prohens, R. (2018-12)
      New multicomponent solid forms of sildenafil have been discovered by means of a combined virtual/experimental cocrystal screening. Coformer selection of candidates was conducted based on an in silico screening method from a database of more than 2000 organic compounds, and the intensive experimental screen produced 23 new solid forms. Since the 12 coformers chosen have a combination of phenol and carboxylic acid groups, a variety of cocrystals, salts, and hybrid salt-cocrystals were discovered and characterized.
    • Mechanistic understanding of competitive destabilization of carbamazepine cocrystals under solvent free conditions

      Alsirawan, M.H.D. Bashir; Lai, X.; Prohens, R.; Vangala, Venu R.; Shelley, P.; Bannan, T.J.; Topping, D.O.; Paradkar, Anant R. (2020-07)
      Mechanistic understanding of competitive destabilization of carbamazepine:nicotinamide and carbamazepine:saccharin cocrystals under solvent free conditions has been investigated. The crystal phase transformations were monitored using hot stage microscopy, variable-temperature powder X-ray diffraction, and sublimation experiments. The destabilization of the two cocrystals occurs via two distinct mechanisms: vapor and eutectic phase formations. Vapor pressure measurements and thermodynamic calculations using fusion and sublimation enthalpies were in good agreement with experimental findings. The mechanistic understanding is important to maintain the stability of cocrystals during solvent free green manufacturing.