Pharmaceutical applications and crystal structures of trehalose and its derivatives.

a-a’-Trehalose dihydrate, a-D-glucopyranosyl-a-D-glucopyranoside, is a naturally occurring sugar composed of two glucose monomers with an a-1,1-glycosidic linkage. Some plants and animals utilise trehalose to facilitate cryptobiosis (life without water), actively synthesising and storing increased amounts in response to water, cold or heat stress. Preformulation profiling of trehalose has been performed, with consideration to solubility, flowability, spray-drying, particle size analysis and thermal studies. Further, planned solid, oral formulation strategies using model drugs (ascorbic acid and nitrofurantoin) were prospectively developed and tested for unwanted stability problems or incompatibilities between active compound and proposed excipients. A stability indicating HPLC assay (using an ODS C8 column), to quantify ascorbic acid recovery from tablets containing trehalose, has been developed, validated, and applied in the context of the tablet matrix. Accelerated storage testing has been undertaken for ascorbic acid tablets under conditions of elevated humidity and heat, with comparisons made to tablets stored under less deleterious conditions. Molecular and physical mixing techniques of nitrofurantoin and sugar were developed and amounts of drug recovered from these mixtures, examined spectroscopically, were compared. Using sucrose and lactose as alternative sugars for mixing with drug, initially intrinsic dissolution testing equipment was used and results compared. Finally comparison between batches of tablets containing trehalose and drug and batches containing comparison sugar and drug were made, showing similar increases in dissolution rate and saturated solubility of poorly water soluble nitrofurantoin as when intrinsic dissolution equipment was used. The molecular conformations of a,a’-trehalose dihydrate and novel carbohydrate derived compounds by single crystal X-ray diffraction have been elucidated. Five unique derivatised compounds were studied: 2,2'3,3'4,4’-hexaacetato-6,6’-bis(isobutanoyl)-a,a’-trehalose hydrate, 2,2’,3,3’,4,6,6'-hepta-O-pivaloyl-a,a’-trehalose, ditrityl a,a’-trehalose hexaacetate, 4,4' -di-O-isobutyroyl-2,2',3,3’,6,6'-hexa-O-acetyl-a,a’-trehalose and a,a’-trehalose octaacetate ethyl acetate solvate. These molecules were derivatised from a,a’-trehalose in order to investigate the role of intermolecular hydrogen bonding within crystalline trehalose, by reducing or abolishing the availability of potential hydrogen bonding sites. The molecular structure elucidation of a,a’-trehalose dihydrate was from a data set collected from a crystal grown and harvested in the laboratory. Neutron diffraction studies of a,a’- trehalose dihydrate were undertaken and H-atom positions were located accurately from the H-atom positions calculated from the X-ray data set.

Grantor dc:publisher.institution

Robert Gordon University

Year dc:date.issued

2004

Author dc:creator

• Clow, Simon Menzies

Advisor dc:contributor.advisor

• P.J. Cox, D.L. Munday, R.R. Moody, D.G. Durham, D. Hansford and S.M. MacManus

• Crystal structures
• Trehalose
• Ascorbic acid
• Nitrofurantoin
• Pharmaceutical application

Language dc:language

en

Identifier

oai:rgu-repository.worktribe.com:2807331
https://doi.org/10.48526/rgu-wt-2807331

OAI identifier oai:identifier

oai:rgu-repository.worktribe.com:2807331