Publications
171 results found
Cheung PCW, Williams DR, 2015, Separation of transition metals and chelated complexes in wastewaters, Environmental Progress & Sustainable Energy, Vol: 34, Pages: 761-783, ISSN: 1944-7442
This review responds to the ongoing needs of wastewater engineers tasked with treating aqueous solutions containing chelated complexes of metal ions, of which nickel citrate in electrodeless plating and copper–EDTA in electronic chip board manufacturing are two key examples. Because of the presence of these sequestering agents, metallic ions cannot be readily precipitated by alkalinity, making a compelling case for the discovery of alternative methods of treatment. This review is a critical appraisal of the varying degrees of success in separation process strategies deployed for the recovery of metallic ions under such challenging chemical conditions. Guidance is provided on making progress toward satisfactory industrial solutions to surmount these difficulties.
Shah UV, Parambil JV, Williams DRM, et al., 2015, Preparation and characterisation of 3D nanotemplates for protein crystallisation, Powder Technology, Vol: 282, Pages: 10-18, ISSN: 0032-5910
Heterogeneous template nucleants are gaining pace as a favoured tool for crystallisation of proteins that may be otherwise difficult to crystallise. A systematic understanding on protein-nucleant interactions has to be developed to enable the development of nucleants for a wide spectrum of biological macromolecules. Thorough characterisation of the nucleants is the key starting point to achieve this aim. This report focuses on the method to produce and characterise functionalised 3D nanotemplates with controlled porosity in the range of 3-22. nm and surface chemistry that can vary from highly hydrophilic to highly hydrophobic in nature. BET and TEM are used to study porosity and pore size distribution while contact angle, XPS and zeta potential are used to investigate surface chemistry of the nucleants. These functionalised 3D nanotemplates are hereby reported to produce protein crystals (concanavalin A and catalase) of different habits without changing any other crystallisation parameters other than the surface chemistry of the templates. This emphasises the potential of 3D nanotemplates with well-ordered porosity and chemistry for further development in protein crystallisation experiments.
Hedberg S, Heng JYY, Williams DR, et al., 2015, Chromatographic tools to predict the stability of mAbs for faster identification of therapeutic candidates, Pages: 1150-1151
Protein-protein molecular interactions are known to be involved in protein solution aggregation behaviour and are a common issue for the manufacturing of therapeutic proteins such as mAbs. Much effort has been employed to gain a better understanding of aggregation, however the mechanisms leading to protein aggregation are still not fully understood. The osmotic second virial coefficient (B22) is a fundamental physiochemical property that describes protein-protein interactions solution, which can be a useful tool to predict aggregation propensity of proteins. One way of predicting aggregation propensity is self-interaction chromatography (SIC), which recently have shown to be a promising tool for better understanding of phase behaviour of proteins. Another technique, cross-interaction chromatography (CIC), has shown to be an even more high-throughput technique than its predecessor with possibly the same capabilities. This work consists of two experimental studies with therapeutic mAbs to improve SIC and CIC as a tool to predict protein aggregation. The first part includes a 10 times scale-down study of therapeutic mAbs from laboratory scale macro-columns to micro-scale columns, which will enable the determination of B22 for the individual protein as well as the cross-virial coefficient, B23, between two proteins. Micro SIC and CIC uses only a few milligrams of mAb in order to obtain a complete formulation study. The results from the first part of the study proved to give good comparable results between the micro and macro scales enabling the use of micro SIC for B22 determinations. The second part of this work presents an extensive formulation study of mAbs, varying pH and salt, as well as the presence of different stabilisers as well as different external factors known to induce aggregation. The B22 and B23 values determined from the formulation study are then correlated with aggregation data obtained from size-exclusion chromatography. It was shown that over all te
Williams DR, 2015, Particle Engineering in Pharmaceutical Solids Processing: Surface Energy Considerations, CURRENT PHARMACEUTICAL DESIGN, Vol: 21, Pages: 2677-2694, ISSN: 1381-6128
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- Citations: 43
Devi S, Williams DR, 2014, Density dependent mechanical properties and structures of a freeze dried biopharmaceutical excipient - Sucrose, EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, Vol: 88, Pages: 492-501, ISSN: 0939-6411
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- Citations: 14
Smith RR, Williams DR, Burnett DJ, et al., 2014, A new method to determine dispersive surface energy site distributions by inverse gas chromatography, Langmuir: the ACS journal of surfaces and colloids, Vol: 30, Pages: 8029-8035, ISSN: 0743-7463
A computational model to predict the relative energy site contributions of a heterogeneous material from data collected by finite dilution–inverse gas chromatography (FD-IGC) is presented in this work. The methodology employed a multisolvent system site filling model utilizing Boltzmann statistics, expanding on previous efforts to calculate “experienced energies” at varying coverage, yielding a retention volume distribution allowing calculation of a surface free energy distribution. Surface free energy distributions were experimentally measured for racemic ibuprofen and β-mannitol powders, the energies of each were found in the ranges 43–52 and 40–55 mJ/m2, respectively, over a surface coverage range of 0–8%. The computed contributions to surface energy values were found to match closely with data collected on macroscopic crystals by alternative techniques (±<1.5 mJ/m2).
Hedberg S, Quigley A, Heng JYY, et al., 2014, Self-interaction chromatography (SIC) of mabs: New methods for estimating the dead volume in SIC and using sic to predict mab stability, Pages: 897-907
Protein-protein molecular interactions are known to be involved in protein solution aggregation behaviour; however the mechanisms leading to protein aggregation are still not fully understood. The osmotic second virial coefficient (B22) is a fundamental physiochemical property that describes proteinprotein interactions in solution, which can be a useful tool to predict aggregation propensity of proteins. This work includes two experimental SIC studies on both model proteins and therapeutic mAbs of different sizes. The first study is an evaluation of two different experimental techniques used to determine SIC dead volumes and the second study uses SIC results for mAb to predict stability. Accurate dead retention volumes are essential for the accurate determinations of B22. The traditional method of estimating dead volume for SIC includes the use of a dead column (without protein immobilised) where the retention volume for proteins can be established. For this technique the dead volume was established for the proteins over a wide range of solution conditions (pH and salt concentrations), and then compared with a new method, where a number of non-interacting dextrans of different molecular weights (MW) (including the MW's of the protein) were employed to find the dead retention volume. The results for the traditional technique with a dead column changed depending on the protein used; only certain model proteins kept a constant dead retention volume when the pH was changing under a constant high salt concentration to minimise protein-surface interactions. Several proteins, including the mAb, exhibited an increased dead retention volume especially when exposed to lower pH. From this it can be concluded that there is no absolute dead volume that can be determined by this technique which are independent of solution conditions. The new technique involving dextrans gives a better overall result for the dead volume for proteins such as mAbs. The second study shows that the SI
Devi S, Williams D, 2013, Morphological and Compressional Mechanical Properties of Freeze-Dried Mannitol, Sucrose, and Trehalose Cakes, JOURNAL OF PHARMACEUTICAL SCIENCES, Vol: 102, Pages: 4246-4255, ISSN: 0022-3549
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- Citations: 20
Quigley A, Heng JYY, Liddell JM, et al., 2013, The accurate measurement of second virial coefficients using self-interaction chromatography: Experimental considerations, EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, Vol: 85, Pages: 1103-1111, ISSN: 0939-6411
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- Citations: 11
Wang GD, Heng JYY, Williams DR, 2013, Dilatometry of powder compacts - Characterizing amorphous-crystalline transformations, POWDER TECHNOLOGY, Vol: 236, Pages: 12-16, ISSN: 0032-5910
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- Citations: 4
Delmas T, Shah UV, Roberts MM, et al., 2013, Crystallisation of the orthorhombic form of acetaminophen: Combined effect of surface topography and chemistry, POWDER TECHNOLOGY, Vol: 236, Pages: 24-29, ISSN: 0032-5910
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- Citations: 16
Khoo JY, Shah UV, Schaepertoens M, et al., 2013, Process-induced phase transformation of carbamazepine dihydrate to its polymorphic anhydrates, POWDER TECHNOLOGY, Vol: 236, Pages: 114-121, ISSN: 0032-5910
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- Citations: 21
Ho R, Naderi M, Heng JYY, et al., 2012, Effect of Milling on Particle Shape and Surface Energy Heterogeneity of Needle-Shaped Crystals, PHARMACEUTICAL RESEARCH, Vol: 29, Pages: 2806-2816, ISSN: 0724-8741
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- Citations: 88
Tsekova DS, Williams DR, Heng JYY, 2012, Effect of surface chemistry of novel templates on crystallization of proteins, CHEMICAL ENGINEERING SCIENCE, Vol: 77, Pages: 201-206, ISSN: 0009-2509
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- Citations: 29
Shah UV, Allenby MC, Williams DR, et al., 2012, Crystallization of Proteins at Ultralow Supersaturations Using Novel Three-Dimensional Nanotemplates, CRYSTAL GROWTH & DESIGN, Vol: 12, Pages: 1772-1777, ISSN: 1528-7483
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- Citations: 31
Shah UV, Williams DR, Heng JYY, 2012, Selective Crystallization of Proteins Using Engineered Nanonucleants, CRYSTAL GROWTH & DESIGN, Vol: 12, Pages: 1362-1369, ISSN: 1528-7483
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- Citations: 48
Quigley A, Williams D, 2012, Second Virial Coefficients as Determined using Self Interaction Chromatography and Protein Aggregation in Solution, BIOPHYSICAL JOURNAL, Vol: 102, Pages: 442A-442A, ISSN: 0006-3495
Parambil JV, Schaepertoens M, Williams DR, et al., 2011, Effects of Oscillatory Flow on the Nucleation and Crystallization of Insulin, CRYSTAL GROWTH & DESIGN, Vol: 11, Pages: 4353-4359, ISSN: 1528-7483
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- Citations: 38
Ho R, Dilworth SE, Williams DR, et al., 2011, Role of Surface Chemistry and Energetics in High Shear Wet Granulation, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 50, Pages: 9642-9649, ISSN: 0888-5885
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- Citations: 31
Heng JYY, Williams DR, 2011, Vapour Sorption and Surface Analysis, Solid State Characterization of Pharmaceuticals, Editors: Storey, Ymén, Publisher: Wiley-Blackwell, ISBN: 9780470659359
This book provides an up-to-date review of the current techniques used to characterize pharmaceutical solids.
Jefferson AE, Williams DR, Heng JYY, 2011, Computing the Surface Energy Distributions of Heterogeneous Crystalline Powders, JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, Vol: 25, Pages: 339-355, ISSN: 0169-4243
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- Citations: 24
Ho R, Hinder SJ, Watts JF, et al., 2010, Determination of surface heterogeneity of D-mannitol by sessile drop contact angle and finite concentration inverse gas chromatography, INTERNATIONAL JOURNAL OF PHARMACEUTICS, Vol: 387, Pages: 79-86, ISSN: 0378-5173
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- Citations: 65
Roberts MM, Heng JYY, Williams DR, 2010, Protein Crystallization by Forced Flow through Glass Capillaries: Enhanced Lysozyme Crystal Growth, CRYSTAL GROWTH & DESIGN, Vol: 10, Pages: 1074-1083, ISSN: 1528-7483
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- Citations: 29
Khoo JY, Heng JYY, Williams DR, 2010, Agglomeration Effects on the Drying and Dehydration Stability of Pharmaceutical Acicular Hydrate: Carbamazepine Dihydrate, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 49, Pages: 422-427, ISSN: 0888-5885
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- Citations: 12
Khoo JY, Williams DR, Heng JYY, 2010, Dehydration Kinetics of Pharmaceutical Hydrate: Effects of Environmental Conditions and Crystal Forms, DRYING TECHNOLOGY, Vol: 28, Pages: 1164-1169, ISSN: 0737-3937
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- Citations: 14
Roskilly SJ, Colbourn EA, Alli O, et al., 2010, Investigating the effect of shape on particle segregation using aMonte Carlo simulation, Powder Technology, Vol: 203, Pages: 211-222
A Monte Carlo simulation has been used to investigate the segregation potential of a range of particulate systems under conditions in which the particles undergo high amplitude low frequency shaking. These systems involve a wide range of binary powder mixtures in which complex particle shapes have been investigated, including plates and rods which represent the real world materials encountered in pharmaceutical systems such as those which include crystalline components. Previous simulations on the segregation propensity of systems with different shapes were limited to spheres and spherocylinders, with relatively low vibrational amplitude drops. A commercial computer application for particle packing—calledMacroPac—has been successfully employed here, as it has been able to model systems that are more complex where the shape variation is much wider. These simulations apply to the case of macroscopic particles, in the absence of air resistance and inter-particle forces. For non-spherical shapes, an ‘effective size’ which relates to the radius of gyration of the particles is determined. Our studies indicate that with high amplitude low frequency shaking, in a mixture of particles with different shapes but with equal volumes, the particles with the larger ‘effective size’, which tend to have a lower packing fraction, segregate to the top
Burnett D, Malde N, Williams D, 2009, Characterizing amorphous materials with gravimetric vapour sorption techniques, Pharmaceutical Technology Europe, Vol: 21, Pages: 41-45, ISSN: 0164-6826
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- Citations: 17
Hwang Y-S, Cho J, Tay F, et al., 2009, The use of murine embryonic stem cells, alginate encapsulation, and rotary microgravity bioreactor in bone tissue engineering, BIOMATERIALS, Vol: 30, Pages: 499-507, ISSN: 0142-9612
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- Citations: 145
Yla-Maihaniemi PP, Heng JYY, Thielmann F, et al., 2008, Inverse gas chromatographic method for measuring the dispersive surface energy distribution for particulates, LANGMUIR, Vol: 24, Pages: 9551-9557, ISSN: 0743-7463
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- Citations: 87
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