ORCID Profile
0000-0002-0402-8954
Current Organisations
University of Exeter
,
Swinburne University of Technology
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Chemical Engineering | Powder and Particle Technology | Chemical Engineering Not Elsewhere Classified | Industrial Chemistry | Organic Chemistry | Pharmaceutical Sciences And Pharmacy | Mineral Processing/Beneficiation | Organic Green Chemistry | Resources Engineering and Extractive Metallurgy | Fluidization And Fluid Mechanics | Pharmaceutical Sciences | Bioprocessing, Bioproduction and Bioproducts |
Expanding Knowledge in Engineering | Human Pharmaceutical Products not elsewhere classified | Management of Solid Waste from Plant Production | Nutraceuticals and Functional foods | Inorganic Industrial Chemicals | Chemical Fertilisers | Organic Industrial Chemicals (excl. Resins, Rubber and Plastics) | Concentrating Processes of Base Metal Ores (excl. Aluminium and Iron Ores) | Treatments (e.g. chemicals, antibiotics) | First Stage Treatment of Ores and Minerals not elsewhere classified | Processed food products and beverages not elsewhere classified | Other
Publisher: Elsevier BV
Date: 10-2016
Publisher: Wiley
Date: 20-03-2016
DOI: 10.1002/APJ.1988
Publisher: Elsevier BV
Date: 02-2004
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 03-2012
Publisher: Elsevier BV
Date: 09-2021
Publisher: MDPI AG
Date: 09-05-2023
DOI: 10.3390/PHARMACEUTICS15051447
Abstract: Particulate amorphous solid dispersions (ASDs) have been recognised for their potential to enhance the performance of various solid dose forms, especially oral bioavailability and macromolecule stability. However, the inherent nature of spray-dried ASDs leads to their surface cohesion/adhesion, including hygroscopicity, which hinders their bulk flow and affects their utility and viability in terms of powder production, processing, and function. This study explores the effectiveness of L-leucine (L-leu) coprocessing in modifying the particle surface of ASD-forming materials. Various contrasting prototype coprocessed ASD excipients from both the food and pharmaceutical industries were examined for their effective coformulation with L-leu. The model rototype materials included maltodextrin, polyvinylpyrrolidone (PVP K10 and K90), trehalose, gum arabic, and hydroxypropyl methylcellulose (HPMC E5LV and K100M). The spray-drying conditions were set such that the particle size difference was minimised, so that it did not play a substantial role in influencing powder cohesion. Scanning electron microscopy was used to evaluate the morphology of each formulation. A combination of previously reported morphological progression typical of L-leu surface modification and previously unreported physical characteristics was observed. The bulk characteristics of these powders were assessed using a powder rheometer to evaluate their flowability under confined and unconfined stresses, flow rate sensitivities, and compactability. The data showed a general improvement in maltodextrin, PVP K10, trehalose and gum arabic flowability measures as L-leu concentrations increased. In contrast, PVP K90 and HPMC formulations experienced unique challenges that provided insight into the mechanistic behaviour of L-leu. Therefore, this study recommends further investigations into the interplay between L-leu and the physico-chemical properties of coformulated excipients in future amorphous powder design. This also revealed the need to enhance bulk characterisation tools to unpack the multifactorial impact of L-leu surface modification.
Publisher: Elsevier BV
Date: 12-2009
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 12-2009
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 08-2014
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 06-2019
Publisher: Informa UK Limited
Date: 16-04-2015
DOI: 10.3109/03639045.2014.908901
Abstract: Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.
Publisher: Wiley
Date: 02-2003
Publisher: Wiley
Date: 25-06-2012
Publisher: Elsevier BV
Date: 06-2001
Publisher: Elsevier BV
Date: 2015
Publisher: arXiv
Date: 2022
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 06-2012
Publisher: Springer Science and Business Media LLC
Date: 09-05-2016
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.EJPB.2008.12.015
Abstract: This study determined the influence of mixing speed and time on the dissolution and deagglomeration of a micronised, poorly water-soluble drug, indomethacin, in lactose interactive mixtures. Mixing occurred in a Turbula mixer dissolution studies were performed using the USP paddle method, and the extent of deagglomeration was determined using modelling strategies and laser diffraction particle sizing of the powder mixtures. During low energy mixing at low rates and short mixing times, dissolution profiles showed an unusual flat asymptote indicating incomplete extents of dissolution caused by agglomerates that did not readily disperse in the dissolution medium. The study showed that increasing both speed and time of mixing increased the extent of dissolution and deagglomeration of the indomethacin powder. Nonlinear least squares modelling of the dissolution data using a sigmoidal equation provided estimates of the extent and rate of dissolution. Mixing speed and time had a much greater influence on the extent of dissolution which was controlled by deagglomeration than on the initial dissolution rate which was related to dispersed indomethacin. While some deagglomeration did occur at higher mixing energies, the deagglomeration of the indomethacin was not complete with only about 58-80% of indomethacin particles overlapping with the primary indomethacin particle size distribution. The significant outcome of this study was that mixing conditions have a major influence on the mixing quality, especially in areas where agglomerate characteristics influence performance.
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 12-2014
Publisher: Informa UK Limited
Date: 26-07-2018
Publisher: Elsevier BV
Date: 03-2004
Publisher: Elsevier BV
Date: 11-2009
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 03-2015
Publisher: BMJ
Date: 10-2016
Publisher: Elsevier BV
Date: 05-2013
Publisher: Wiley
Date: 20-03-2013
DOI: 10.1002/AIC.14024
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.WATRES.2015.04.021
Abstract: Dried sludge is preferred when the sludge is either to be incinerated or used as a soil amendment. This paper focuses on superheated steam drying which has many benefits, because the system is totally enclosed, thereby minimising odours and particulate emissions. This work reports on field trials at a wastewater treatment plant where anaerobically digested sludge is dried immediately after being dewatered by belt press. The trials showed that unlike previous off-site tests, the sludge could be dried without the addition of a filter aid at a low production rate. However, the trials also confirmed that the addition of the lignite (brown coal) into the anaerobically digested sludge led to a more productive drying process, improved product quality and a greater fraction of the product being in the desired product size range. It is concluded that these results were achieved because the lignite helped to control the granule size in the dryer. Furthermore neither Salmonella spp or E coli were detected in the dried s les. Tests on spontaneous combustion show that this risk is increased in proportion to the amount of lignite used as a drying aid.
Publisher: Elsevier BV
Date: 06-2009
Publisher: Elsevier BV
Date: 11-2010
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 11-2010
Publisher: Wiley
Date: 28-04-2009
DOI: 10.1002/AIC.11772
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 09-2022
Publisher: Wiley
Date: 29-05-2015
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.EJPS.2015.07.016
Abstract: This study investigates the effects of a variety of coating materials on the flowability and dissolution of dry-coated cohesive ibuprofen powders, with the ultimate aim to use these in oral dosage forms. A mechanofusion approach was employed to apply a 1% (w/w) dry coating onto ibuprofen powder with coating materials including magnesium stearate (MgSt), L-leucine, sodium stearyl fumarate (SSF) and silica-R972. No significant difference in particle size or shape was measured following mechanofusion with any material. Powder flow behaviours characterised by the Freeman FT4 system indicated coatings of MgSt, L-leucine and silica-R972 produced a notable surface modification and substantially improved flow compared to the unprocessed and SSF-mechanofused powders. ToF-SIMS provided a qualitative measure of coating extent, and indicated a near-complete layer on the drug particle surface after dry coating with MgSt or silica-R972. Of particular note, the dissolution rates of all mechanofused powders were enhanced even with a coating of a highly hydrophobic material such as magnesium stearate. This surprising increase in dissolution rate of the mechanofused powders was attributed to the lower cohesion and the reduced agglomeration after mechanical coating.
Publisher: Elsevier BV
Date: 09-2002
Abstract: The kinetics of drop penetration were studied by filming single drops of several different fluids (water, PEG200, PEG600, and HPC solutions) as they penetrated into loosely packed beds of glass ballotini, lactose, zinc oxide, and titanium dioxide powders. Measured times ranged from 0.45 to 126 s and depended on the powder particle size, viscosity, surface tensions, and contact angle. The experimental drop penetration times were compared to existing theoretical predictions by M. Denesuk et al. (J. Colloid Interface Sci.158, 114, 1993) and S. Middleman ("Modeling Axisymmetric Flows: Dynamics of Films, Jets, and Drops," Academic Press, San Diego, 1995) but did not agree. Loosely packed powder beds tend to have a heterogeneous bed structure containing large macrovoids which do not participate in liquid flow but are included implicitly in the existing approach to estimating powder pore size. A new two-phase model was proposed where the total volume of the macrovoids was assumed to be the difference between the bed porosity and the tap porosity. A new parameter, the effective porosity epsilon(eff), was defined as the tap porosity multiplied by the fraction of pores that terminate at a macrovoid and are effectively blocked pores. The improved drop penetration model was much more successful at estimating the drop penetration time on all powders and the predicted times were generally within an order of magnitude of the experimental results.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier
Date: 2007
Publisher: Elsevier BV
Date: 04-01-2008
DOI: 10.1016/J.IJPHARM.2007.06.022
Abstract: A model that describes the relationship between roller-compaction conditions and tablet strength is proposed. The model assumes that compaction is cumulative during roller compaction and subsequent granule compaction, and compact strength (ribbon and tablet) is generated irreversibly as if strength is controlled by plastic deformation of primary particles only. Roller-compaction is treated as a compaction step where the macroscopic ribbon strength is subsequently destroyed in milling. This loss in strength is irreversible and tablets compressed from the resulting granulation are weaker than those compressed by direct compression at the same compression force. Roller-compacted ribbons were produced at a range of roll forces for three formulations and subsequently milled and compacted into tablets. Once the total compaction history is taken in account, the compaction behavior of the uncompacted blends and the roller-compacted granules ultimately follow a single master compaction curve--a unified compaction curve (UCC). The model successfully described the compaction behavior of DC grade starch and formulations of lactose monohydrate with 50% or more microcrystalline cellulose, and may be more generally applicable to systems containing significant proportions of any plastically deforming material, including MCC and starch.
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.XPHS.2016.07.017
Abstract: This study aims at testing the feasibility of a single-step coating process to produce a powder formulation of active and inactive ingredients for direct compression. A cohesive ibuprofen powder was coprocessed with a coating material, a binder (polyvinylpyrrolidone K25), and a superdisintegrant (crospovidone). Magnesium stearate (MgSt), l-leucine, and silica were selected as coating materials (1% w/w). A coprocessed powder without any coating material was employed as a control. Coating with MgSt, l-leucine, or silica produced significantly improved powder flow in comparison to the control batch. Robust tablets were produced from the processed powders for each coating material. The tablets compacted using the coated powders with MgSt or l-leucine also exhibited significantly lower tablet ejection forces than the control batch, demonstrating their lubrication effect. Furthermore, the disintegration time and dissolution rates of these tablets made of the formulations coprocessed with lubricants were enhanced, even for those coated with the hydrophobic material such as MgSt that has been previously reported to inhibit dissolution. However, the tablets made with silica-coated powders would not disintegrate. This study indicated the feasibility of a single-step dry coating process to produce powders with both flow-aid and lubrication effects, which are suitable for direct compression.
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 04-2002
Publisher: Springer Science and Business Media LLC
Date: 09-02-2013
DOI: 10.1007/S00125-013-2851-Y
Abstract: Sirtuin (SIRT)3 is a mitochondrial protein deacetylase that regulates reactive oxygen species (ROS) production and exerts anti-inflammatory effects. As chronic inflammation and mitochondrial dysfunction are key factors mediating pancreatic beta cell impairment in type 2 diabetes, we investigated the role of SIRT3 in the maintenance of beta cell function and mass in type 2 diabetes. We analysed changes in SIRT3 expression in experimental models of type 2 diabetes and in human islets isolated from type 2 diabetic patients. We also determined the effects of SIRT3 knockdown on beta cell function and mass in INS1 cells. SIRT3 expression was markedly decreased in islets isolated from type 2 diabetes patients, as well as in mouse islets or INS1 cells incubated with IL1β and TNFα. SIRT3 knockdown in INS1 cells resulted in lowered insulin secretion, increased beta cell apoptosis and reduced expression of key beta cell genes. SIRT3 knockdown also blocked the protective effects of nicotinamide mononucleotide on pro-inflammatory cytokines in beta cells. The deleterious effects of SIRT3 knockdown were mediated by increased levels of cellular ROS and IL1β. Decreased beta cell SIRT3 levels could be a key step in the onset of beta cell dysfunction, occurring via abnormal elevation of ROS levels and lification of beta cell IL1β synthesis. Strategies to increase the activity or levels of SIRT3 could generate attractive therapies for type 2 diabetes.
Publisher: Wiley
Date: 29-10-2010
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 2016
Publisher: Wiley
Date: 29-03-2019
Publisher: American Chemical Society (ACS)
Date: 23-04-2019
Publisher: Elsevier BV
Date: 2010
Publisher: Wiley
Date: 13-05-2012
Publisher: Humana Press
Date: 06-11-2009
DOI: 10.1007/978-1-60761-421-0_3
Abstract: Human blood dendritic cells (DCs) are a rare, heterogeneous cell population that comprise approximately 1% of circulating peripheral blood mononuclear cells (PBMCs). Their isolation has been confounded by their scarcity and lack of distinguishing markers and their characterisation perplexed by the recent discovery of phenotypic and functionally distinct subsets. Human blood DCs are broadly defined as leukocytes that are HLA-DR positive and lack expression of markers specific for T cell, B cell, NK cell, monocyte and granulocyte lineages. They can be sub ided into the CD11c(-) (CD123(+)CD303(+)CD304(+)) plasmacytoid DC and CD11c(+) myeloid DC, which can be further sub ided into three subsets based on differential expression of CD1c, CD141 and CD16. DC can be isolated from peripheral blood by using an initial density gradient centrifugation step to enrich for mononuclear cells followed by immunomagnetic depletion of cells expressing markers specific for leukocyte lineages and undesired DC subsets. Subsequent flow cytometry-based cell sorting allows the isolation of highly pure in idual DC subsets that can then be used for functional studies.
Publisher: Informa UK Limited
Date: 22-01-2018
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 11-2021
Publisher: Informa UK Limited
Date: 12-10-2013
DOI: 10.3109/03639045.2012.719233
Abstract: Foam granulation technology is a new wet granulation approach for pharmaceutical formulations. This study evaluates the performance of foam and spray granulation in achieving uniform drug distribution using a model formulation. To observe wetting and nuclei formation, single drop/foam penetration experiments were performed on a static powder bed comprised of varying compositions of hydrophilic/hydrophobic glass ballotini, and hydrophilic lactose/hydrophobic salicylic acid respectively. High shear granulation experiments were performed in a 5L mixer using varying compositions of hydrophilic lactose and hydrophobic salicylic acid. Four percent hydroxylpropyl methylcellulose (HPMC) solution was delivered at 90 g/min as either a foam (92% FQ) or an atomized spray whilst recording impeller power consumption. After drying, the granule size distribution was measured and the granule composition was estimated using gravimetric filtration in methanol. Foam penetration was less dependent on the powder hydrophobicity compared to drop penetration. For glass ballotini powder mixtures, foam induced nucleation created nuclei with relatively uniform structure and size regardless of the powder hydrophobicity. For salicylic acid and lactose mixtures, increasing the proportion of salicylic acid reduced the nuclei granule size for both foam and drop binder addition. The granule drug distribution was not significantly affected by the binder addition method. Processing conditions, including liquid binder amount, impeller speed, wet massing, and the wettability properties of the formulation were the dominant factors for delivering homogeneous granules. The study reveals that foam and spray granulation involve different nucleation mechanisms - spray tends to incur early liquid penetration whereas foam granulation operates well in mechanical dispersion.
Publisher: Elsevier BV
Date: 07-2009
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 04-2013
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2015
End Date: 12-2021
Amount: $375,900.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2014
End Date: 06-2017
Amount: $400,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 01-2008
End Date: 12-2011
Amount: $390,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 01-2007
End Date: 07-2011
Amount: $135,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2013
End Date: 12-2016
Amount: $354,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2020
End Date: 12-2025
Amount: $3,574,272.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2020
End Date: 07-2027
Amount: $35,000,000.00
Funder: Australian Research Council
View Funded Activity