Guaquière, Juliette Ségolène;
(2002)
Studies of Spray-Dried Particles for Inhalation.
Doctoral thesis (Ph.D), University College London.
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Abstract
Multicomponent spray-dried particles composed of lactose, albumin and dipalmitoylphosphatidylcholine (DPPC) may have potential in pulmonary drug delivery. Physical stability, which is central to functionality of such particles, has not yet been studied. The aim of this work was to investigate the effects of composition and preparation methodology on long term stability of the particles. The multicomponent particles were formed by spray-drying the mixture of solutions from the three components. Water was used to solubilise the dissacharide and the albumin, whereas it was necessary to use ethanol to solubilise DPPC. To determine the effect of the ethanol on lactose stability, particles comprised of lactose alone were prepared using different proportions of aqueous ethanolic co-solvents. Isothermal microcalorimetry confirmed the amorphous structure of the spray-dried lactose. The presence of residual solvent (established using Thermogravimetric analysis) plasticised the samples causing the glass transition temperature (Tg) (measured using modulated DSC) to decrease. Increased proportions of ethanol resulted in reducing the nucleation time as observed by Dynamic Vapour Sorption. Analysis by inverse gas chromatography indicated that a co-solvent at 50% v/v ethanol has altered the molecular organisation of the final amorphous structure.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Studies of Spray-Dried Particles for Inhalation. |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis Digitised by Proquest. |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10121612 |
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