Polymorphism in p-aminobenzoic acid

Aurora J. Cruz-Cabeza, Roger J. Davey, Iain D.H. Oswald, Martin R. Ward, Isaac J. Sugden

Research output: Contribution to journalArticle

6 Citations (Scopus)
12 Downloads (Pure)


We review the polymorphism of p-aminobenzoic acid (pABA), a model drug compound whose crystallisation and polymorphic behaviour has been extensively studied in recent years. Beyond the well-known and characterised α and β forms, pABA also crystallises as a γ polymorph, which is structurally similar to the α form. In addition we also compare the newly reported δ form, obtained by high pressure crystallisation and through compression of the α-form. A structural analysis and comparison of all of the forms is presented, the conditions by which each of them is obtained summarised. Crystal structure prediction calculations have also been carried out in order to probe the solid form energy landscape of this compound. The overall picture of the polymorphism of pABA, reveals, surprisingly, the rarity of the β form.
Original languageEnglish
Pages (from-to)2034-2042
Number of pages9
Issue number13
Early online date22 Jan 2019
Publication statusPublished - 7 Apr 2019


  • p-aminobenzoic acid
  • polymorph
  • review

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  • Projects


    Discovery of delta polymorph of para-aminobenzoic acid

    Ward, M. (Creator), Younis, S. (Contributor), Cruz-Cabeza, A. (Contributor), Bull, C. L. (Contributor), Funnell, N. (Contributor) & Oswald, I. (Creator), University of Strathclyde, 21 Jan 2019


    Research Output

    • 6 Citations
    • 1 Article

    Discovery and recovery of delta p-aminobenzoic acid

    Ward, M. R., Younis, S., Cruz-Cabeza, A. J., Bull, C. L., Funnell, N. P. & Oswald, I. D. H., 7 Apr 2019, In : CrystEngComm. 21, 13, p. 2058-2066 9 p.

    Research output: Contribution to journalArticle

    Open Access
  • 4 Citations (Scopus)
    7 Downloads (Pure)


    • 1 Oral presentation

    Recovery of high pressure solid forms to ambient pressure

    Martin Ward (Speaker)

    9 Jul 2019

    Activity: Talk or presentation typesOral presentation

    Cite this

    Cruz-Cabeza, A. J., Davey, R. J., Oswald, I. D. H., Ward, M. R., & Sugden, I. J. (2019). Polymorphism in p-aminobenzoic acid. CrystEngComm, 21(13), 2034-2042. https://doi.org/10.1039/C8CE01890A