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Title: The surface characterisation of pharmaceutical mini-tablets using thermal probe techniques
Author: Peacock, Joanne
ISNI:       0000 0004 5352 2646
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2014
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This thesis assesses the ability of a range of novel thermo-analytical techniques to determine the spatial distribution of components across the surface of pharmaceutical mini-tablets. Such information is of use in formulation development, as the surface is the point at which a solid dosage form comes into contact with the environment, and where drug stability and excipient functionality are critical. Mini-tablets provide a good model system for surface characterisation, as they have much higher surface area to volume ratios than conventionally sized tablets. Five excipients and two drugs, as powders and after compaction, were individually characterised by the following techniques: scanning electron microscopy (SEM), variable temperature infrared spectroscopy (VT-IR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), micro-thermal analysis (micro-TA), nano-thermal analysis (nano-TA) and transition temperature microscopy (TTM). Compacts of mixed systems were tested using AFM, micro-TA, nano-TA and TTM, building up the complexity to 4-component systems for excipient-only mixtures and 5-component systems for drug-loaded mixtures. Micro-TA, nano-TA and TTM were able to detect each component in all of the multi-component compacts, but AFM could not differentiate between them in complex systems. The study was then repeated on realistic mini-tablet formulations, confirming these initial results. Additionally, Raman microspectroscopy was performed on the mini-tablets as a corroborative technique, this method being based on a different physical phenomenon. In conclusion, the thermal probe techniques (micro-TA, nano-TA and TTM) were shown to be sufficiently discriminating to allow the spatial mapping of components across the surface of realistic mini-tablet formulations. Hence, these techniques could be used alongside spectroscopic techniques in the analysis of complex surfaces. However, some serious issues with the automated analysis and data display functions in the TTM software were identified, which could lead to misinterpretation of the results. Potential corrective measures were suggested to alleviate these concerns and improve experimental reliability.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available