Pharmaceutical solids and exploring chiral resolution using cocrystallization

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Khandavilli, Udaya Bhaskara Rao
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University College Cork
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This thesis is concerned with the solid-state and physicochemical properties of multi-component forms of model systems and active pharmaceutical ingredients, with particular emphasis on cocrystallization; a method that allow formation of multi-component forms for compounds with non-ionizable or weakly ionisable functional groups. The research has been divided into four chapters. Chapter One discusses and illustrates the literature for the solid-state of organic compounds; topics covered include polymorphism, hydrates, solvates, cocrystallization and salt formation, Chapter Two describes the synthesis and cocrystallization of model drugs with non-ionisable functional groups. Two series of phenylcarboximides with different alkyl group substitution (varying from methyl to tert-butyl) on a chiral centre either α or β to the amide functional group have been synthesised and their solid-state properties examined. Cocrystallization studies reveal that the drug salicylic acid is a reliable coformer with all the amides examined. The polymorphic behaviour of the cocrystals has been fully explored. Chapter Three examines cocrystallization and salt formation as ways to improve the poor solubility associated with nutraceutical compounds, by investigating two model nutraceuticals: sinapic acid and naringenin. Their solid-state forms, solubility and dissolution properties were determined. Chapter Four describes multi-component forms of actual drugs, namely sulpiride and probenecid. Inorganic and organic salts of sulpiride were synthesized and structural and physicochemical properties. Transfer of mechanical flexibility from the drug to its multi-component form has been demonstrated for a GRAS coformer. The design of ternary cocrystals using compounds with phenolic and carboxylic acid functional groups was envisaged and achieved.
Polymorph , Co-crystal , Pharmaceutical salt , Conglomerate , Nutraceuticals , Kryptoracemic , Co-crystal polymorph , Salt co-crystal , Ternary co-crystal , Bending crystals
Khandavilli, U. B. 2017. Pharmaceutical solids and exploring chiral resolution using cocrystallization. PhD Thesis, University College Cork.
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