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Updated: Aug 31, 2026

A Package of Established Analytical Tools to Investigate the Solid-State Alteration of Lipid-Based Excipients
Published on: August 9, 2022
Two new paracetamol/dioxane solvates--a system exhibiting a reversible solid-state phase transformation
Ranko M Vrcelj1, Nathan I B Clark, Alan R Kennedy
1Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building, 295 Cathedral Street, Glasgow, G1 1XL, UK. rmv22@cam.ac.uk
Abstract:
This work reports on the crystal structures of two dioxane solvates of paracetamol that are true polymorphs. The high temperature phase is an orthorhombic form, space group Pbca, Z = 8, a = 12.6078(3) A, b = 12.1129(2) A, c = 13.4138(3) A, V = 2048.52(7) A(3), (at 295 K) and the low temperature form is monoclinic, space group P21/c, Z = 4, a = 12.325(6) A, b = 11.965(4) A, c = 13.384(6) A, beta = 92.01 degrees, V = 1972.6(14)A(3) (at 123 K). The structures of these polymorphs are described as is the interrelationship between the two structures. In addition to the structural interrelationship, it is shown that the two forms undergo a reversible phase transformation. Desolvation of either form generates the stable monoclinic phase of paracetamol.
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