Saudi Cultural Missions Theses & Dissertations
Permanent URI for this communityhttps://drepo.sdl.edu.sa/handle/20.500.14154/10
Browse
2 results
Search Results
Item Restricted Expanding the Performance and Functionality of Air-Jet Dry Powder Inhalers Across Multiple Applications(Saudi Digital Library, 2025) Aladwani, Ghali H; Longest, WorthThis dissertation aims to expand the performance and functionality of air-jet dry powder inhaler (DPI) applications through the development of a next-generation, mesh-nebulizer-based, and scalable spray dryer for the production of pharmaceutical aerosols, along with new spray-dried formulation production methods, novel formulations, and new air-jet DPI components for aerosol delivery to both infants and adults. The first aim focused on the development of a custom small-particle spray drying system capable of integrating vibrating mesh nebulizer technologies in various configurations for the production of excipient enhanced growth (EEG) formulations. This flexible system enabled efficient production of both small- and large-particle powders for pulmonary and nasal-targeted drug delivery. Additional advantages of the developed spray dryer included a significant increase in production rates using dual- and triple-mesh nebulizer configurations. Formulations produced in this work included a synthetic lung surfactant formulation (SLS-EEG), which demonstrated improved aerosol performance with a fine particle fraction (FPF < 5 µm) of 89.9% and a reduction in pre-separator loss from 30% to 6% when tested using the Next Generation Impactor (NGI) and compared with powder previously produced using the commercial Buchi B-90 Nano Spray Dryer. The second aim of this work focused on the development and evaluation of an infant manual cyclic (MC) air source for operating air-jet DPIs, delivering consistent and repeatable low air volumes (up to 17 mL) in compliance with Lung Ventilator Code ISO 10651-4 when the device is paired with an infant air-jet DPI. A compact version of the MC air source was also developed for various air-jet DPI applications, including nasal-targeted delivery. Together, these aims advanced the performance of air-jet DPIs through the development of a scalable and mesh-nebulizer based spray dryer capable of producing efficient EEG formulations, and the development of new DPI components suitable for both pediatric and adult populations.15 0Item Restricted Influence of diphenyliodonium hexafluorophosphate salt (DPI) and ion-releasing glass fillers (45S5) on physical, mechanical and chemical properties of model resin composite formulations(University of Manchester, 2024-07-30) Alotaibi, Saad; Silikas, Nick; Watts, DavidRecurrent dental caries is a major reason for resin composite restoration replacement. 45S5 Ion-releasing glass (IRG) fillers are promising for functionalizing resin composites. They aid in hydroxyapatite deposition and remineralization of dental tissues. Diphenyl iodonium hexafluorophosphate (DPI) is a UV light initiator that replenishes Camphorquinone (CQ) by replacing inactive radicals with phenyl active radicals. The aim of this research was to explore the interactive effect of DPI and IRG on short and long-term material properties. Model resin-composites with varying amounts of IRG were prepared using a UDMA/TEGDMA resin system and either a unary or binary (includes DPI) photo-initiator system. Polymerization related properties such as degree of conversion (DC), shrinkage strain (SS) and depth of cure (DoC) were measured. IRG negatively impacted DC and DoC when higher content was used while DPI improved both DC and DoC. The SS was lower in the unary group and with higher IRG content confirming an inverse relation between DC and SS. Martens hardness (HM) and related parameters, indentation modulus (EIT) and creep (CIT), as well as the effect of storage in water or ethanol on these parameters were tested. HM and EIT decreased and CIT increased linearly as the amount of IRG is increased. Deterioration of HM and EIT through aging was more pronounced in specimens containing higher IRG amount. DPI showed higher HM, EIT and lower CIT only at higher IRG content compared to the unary group. Water sorption, solubility, hygroscopic dimensional changes and ions release were assessed. IRG significantly increased water sorption, solubility and hygroscopic expansion. Inclusion of DPI reduced water sorption, solubility and hygroscopic expansion. Release of calcium, sodium and phosphate were dose dependent on IRG. This study concluded that 45S5 IRG, while offering potential means of remineralisation, diminished the material’s overall properties. The inclusion of DPI enhanced the polymerization and overall properties of the tested model resin composites.10 0