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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science 6 February 2017, Johannesburg. / Polymorphism is not only limited to single component systems. Co-crystals have exhibited polymorphism and various polymorphic co-crystals have been reported. Polymorphism in co-crystals presents an expansion of the optimization space around a pharmaceutical compound and also offers the opportunity to develop novel patentable material. Polymorphism of pharmaceutical co-crystals was investigated by means of an exhaustive data mining survey and the formation of polymorphic co-crystals. The search was performed using the Cambridge Structural Database (CSD). The search aimed to find and tally neutral pharmaceutical co-crystals which are polymorphic. The survey of the CSD showed that 14% of the pharmaceutical co-crystals were polymorphic. The co-crystal of theophylline and 3,4-dihydroxybenzoic acid was found to be polymorphic and the novel polymorph was synthesized and characterized. The co-crystals were characterized by x-ray crystallographic techniques and Differential Scanning Calorimetry. The single crystals of carbamazepine and cinnamic acid was grown and characterized by SCXRD for the first time. The single crystal data was able to show that the hydrogen bonding packing that was modelled in the literature is incorrect. / MT2017

Thesis ( Ph.D.) -- McMaster University, 1997. / Computer disk in pocket. Includes bibliographical references. Also available via World Wide Web.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: crystal growth; monolayer; polymorph. Includes bibliographical references (leaves 106-120).

Thesis (Ph.D.) -- University of Rhode Island, 2007 / Typescript. Includes bibliographical references (leaves 95-101).

Thesis (Ph.D.) -- University of Rhode Island, 2008. / Typescript. Includes bibliographical references (leaves 125-134).

A Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. 21 May 2015 / Crystal polymorphism is the capacity of a solid crystalline form to exist in more than one structural arrangement. In the pharmaceutical setting investigations into the polymorphic forms of potential drugs are of vital importance since different crystalline forms can affect bioavailability, mechanical, thermal, and chemical properties. One such example is isonicotinic acid-(1-phenylethylidene) hydrazide (IPH), a derivative of the popular drug isoniazid (used as first line treatment against Mycobacterium tuberculosis) was found to crystallise in six different polymorphic forms. Each crystal structure was determined using X-ray diffraction techniques and including the thermal phase relationships of the polymorphic compound were delineated. In addition to polymorph elucidation, isonicotinic acid-(1-phenylethylidene) hydrazide was modified with –OH and –NH2 at various aromatic positions, creating geometric pyridyl isomers. In-depth studies of these pyridyl isomers revealed a diverse range of supramolecular aggregates. Preliminary thermal screening suggests that only a small selection of these pyridyl isomers present potential polymorphic activity for further study.

The purpose of this study was to investigate the polymorphism of a group of related compounds. Special emphasis was placed upon the temperature at which transitions occurred and a possible correlation of these temperatures with other properties of the compounds.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Rousseau, Ronald; Committee Member: Meredith, Carson; Committee Member: Prausnitz, Mark; Committee Member: Teja, Amyn; Committee Member: Wilkinson, Angus. Part of the SMARTech Electronic Thesis and Dissertation Collection.