Date of Award
Master of Science
A substance that crystallizes into different, but chemically identical, crystalline forms exhibits polymorphism. Polymorphism is generally undesirable in the pharmaceutical industry because properties such as dissolution rate (which, in turn, influences bioavailability), stability, and mechanical compression are intimately linked to crystalline structure. Each polymorph is expected to have a different thermodynamic stability in a particular solvent. One method to determine the thermodynamic stability is by observing the solid-liquid interfacial energy of the polymorphs. In this thesis, the polymorphs of paracetamol (p-Hydroxyacetanilide) crystals in water are studied with molecular dynamics simulation as a first step toward understanding the molecular-level origins of polymorphism. Monoclinic (form I) and orthorhombic (form II) are the known polymorphs of paracetamol. The potential energies of the crystal-water interface for these polymorphs are calculated and the interfacial energies of the (1̄00), (100), (01̄0), (010), (001̄), and (001) faces of each crystal structure are examined to study the relative interaction between the crystal and water at different crystal faces.
Yani, Yin, "Solid-liquid interfacial energy of the polymorphs of paracetamol" (2006). Retrospective Theses and Dissertations. 19064.