Imperial College London

ProfessorDarylWilliams

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Particle Science
 
 
 
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Contact

 

+44 (0)20 7594 5611d.r.williams Website

 
 
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Location

 

439ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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126 results found

Mohd Azmi LH, Williams D, Ladewig B, 2021, Polymer-assisted modification of metal-organic framework MIL-96 (Al): influence of HPAM concentration on particle size, crystal morphology and removal of harmful environmental pollutant PFOA, Chemosphere, Vol: 262, Pages: 1-9, ISSN: 0045-6535

A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.

Journal article

Grape ES, Flores JG, Hidalgo T, Martínez-Ahumada E, Gutiérrez-Alejandre A, Hautier A, Williams DR, O'Keeffe M, Öhrström L, Willhammar T, Horcajada P, Ibarra IA, Inge AKet al., 2020, A Robust and Biocompatible Bismuth Ellagate MOF Synthesized Under Green Ambient Conditions., J Am Chem Soc, Vol: 142, Pages: 16795-16804

The first bioinspired microporous metal-organic framework (MOF) synthesized using ellagic acid, a common natural antioxidant and polyphenol building unit, is presented. Bi2O(H2O)2(C14H2O8)·nH2O (SU-101) was inspired by bismuth phenolate metallodrugs, and could be synthesized entirely from nonhazardous or edible reagents under ambient aqueous conditions, enabling simple scale-up. Reagent-grade and affordable dietary supplement-grade ellagic acid was sourced from tree bark and pomegranate hulls, respectively. Biocompatibility and colloidal stability were confirmed by in vitro assays. The material exhibits remarkable chemical stability for a bioinspired MOF (pH = 2-14, hydrothermal conditions, heated organic solvents, biological media, SO2 and H2S), attributed to the strongly chelating phenolates. A total H2S uptake of 15.95 mmol g-1 was recorded, representing one of the highest H2S capacities for a MOF, where polysulfides are formed inside the pores of the material. Phenolic phytochemicals remain largely unexplored as linkers for MOF synthesis, opening new avenues to design stable, eco-friendly, scalable, and low-cost MOFs for diverse applications, including drug delivery.

Journal article

Gorla S, Diaz-Ramirez ML, Abeynayake NS, Kaphan DM, Williams DR, Martis V, Lara-Garcia HA, Donnadieu B, Lopez N, Ibarra IA, Montiel-Palma Vet al., 2020, Functionalized NU-1000 with an Iridium Organometallic Fragment: SO2 Capture Enhancement, ACS APPLIED MATERIALS & INTERFACES, Vol: 12, Pages: 41758-41764, ISSN: 1944-8244

Journal article

Zárate JA, Domínguez-Ojeda E, Sánchez-González E, Martínez-Ahumada E, López-Cervantes VB, Williams DR, Martis V, Ibarra IA, Alejandre Jet al., 2020, Reversible and efficient SO2 capture by a chemically stable MOF CAU-10: experiments and simulations., Dalton Trans, Vol: 49, Pages: 9203-9207

The adsorption of sulphur dioxide (SO2) in CAU-10 is obtained with the use of advanced experimental and computational tools to gain insight into the molecular mechanisms responsible for the adsorption of SO2. It is shown that the adsorption by CAU-10 is highly energy efficient and that van der Waals interactions are the driving force that controls adsorption in this system.

Journal article

Martinez-Ahumada E, Diaz-Ramirez ML, Lara-Garcia HA, Williams DR, Martis V, Jancik V, Lima E, Ibarra IAet al., 2020, High and reversible SO2 capture by a chemically stable Cr(III)-based MOF, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 8, Pages: 11515-11520, ISSN: 2050-7488

Journal article

Mohd Azmi LH, Williams D, Ladewig B, 2020, Can metal organic frameworks outperform adsorptive removal of harmful phenolic compound 2-chlorophenol by activated carbon?, Chemical Engineering Research and Design, Vol: 158, Pages: 102-113, ISSN: 0263-8762

Removal of persistent organic compounds from aqueous solutions is generally achieved using adsorbent like activated carbon (AC) but it suffers from limited adsorption capacity due to low surface area. This paper describes a pioneering work on the adsorption of an organic pollutant, 2-chlorophenol (2-CP) by two MOFs with high surface area and water stability; MIL-101 and its amino-derivative, MIL-101-NH2. Although MOFs have higher surface area than AC, the latter was proven better having the highest equilibrium 2-CP uptake (345 mg g−1), followed by MIL-101 (121 mg g−1) and MIL-101-NH2 (84 mg g−1). Used MIL-101 could be easily regenerated multiple times by washing with ethanol and even showed improved adsorption capacity after each washing cycle. These results can open the doors to meticulous adsorbent selection for treating 2-CP-contaminated water.

Journal article

Hunter-Sellars E, Tee JJ, Parkin IP, Williams DRet al., 2020, Adsorption of volatile organic compounds by industrial porous materials: Impact of relative humidity, MICROPOROUS AND MESOPOROUS MATERIALS, Vol: 298, ISSN: 1387-1811

Journal article

Ngeow YW, Williams DR, Chapman A, Heng JYYet al., 2020, Surface Energy Mapping of Modified Silica Using IGC Technique at Finite Dilution, ACS OMEGA, Vol: 5, Pages: 10266-10275, ISSN: 2470-1343

Journal article

Hakim Mohd Azmi L, Williams DR, Ladewig BP, 2020, Polymer-Assisted Modification of Metal-Organic Framework MIL-96 (Al): Influence on Particle Size, Crystal Morphology and Perfluorooctanoic Acid (PFOA) Removal

<jats:p>&lt;div&gt;&lt;b&gt;Abstract&lt;/b&gt;&lt;/div&gt;&lt;div&gt;A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve &gt;200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.&lt;br&gt;&lt;/div&gt;</jats:p>

Journal article

Martinez-Ahumada E, Lopez-Olvera A, Jancik V, Sanchez-Bautista JE, Gonzalez-Zamora E, Martis V, Williams DR, Ibarra IAet al., 2020, MOF Materials for the Capture of Highly Toxic H2S and SO2, ORGANOMETALLICS, Vol: 39, Pages: 883-915, ISSN: 0276-7333

Journal article

Duralliu A, Matejtschuk P, Stickings P, Hassall L, Tierney R, Williams DRet al., 2020, The Influence of Moisture Content and Temperature on the Long-Term Storage Stability of Freeze-Dried High Concentration Immunoglobulin G (IgG), PHARMACEUTICS, Vol: 12

Journal article

Cherukupally P, Sun W, Wong APY, Williams DR, Ozin GA, Bilton AM, Park CBet al., 2020, Surface-engineered sponges for recovery of crude oil microdroplets from wastewater (vol 321, pg 784, 2019 ), NATURE SUSTAINABILITY, Vol: 3, Pages: 161-161, ISSN: 2398-9629

Journal article

Hunter-Sellars E, Saenz-Cavazos PA, Houghton AR, McIntyre SR, Parkin IP, Williams DRet al., 2020, Sol–Gel Synthesis of High-Density Zeolitic Imidazolate Framework Monoliths via Ligand Assisted Methods: Exceptional Porosity, Hydrophobicity, and Applications in Vapor Adsorption, Advanced Functional Materials, ISSN: 1616-301X

© 2020 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH Monolithic ZIF-8 and ZIF-67 adsorbents are synthesized at room temperature using a novel, ligand-assisted method. Despite reductions in crystallinity within some of the samples, monolithic zeolitic imidazolate frameworks (ZIFs) have superior volume-relative microporosity, total porosity, and surface areas relative to their particulate counterparts due to increased density. Samples synthesized using a single modulator, n-butylamine, have a hierarchical porosity resulting in improved adsorption capacities in mid- to high- sorbate pressure regions. ZIF-67 monoliths produced through mixed-modulator synthesis, n-butylamine and 1-methylimidazole, are almost entirely microporous. Vapor adsorption isotherms find that, whilst their amorphous content results in increased water uptake, monolithic ZIFs are found to possess higher surface and adsorption hydrophobicity than traditional non-polar adsorbents. Cosorption measurements with a common VOC toluene, under humid conditions, find that these monolithic ZIF samples outperform powder equivalents, with the mixed-modulator ZIF-67 monolith capturing 28% more VOC compared to the powder ZIFs studied due to its superior volumetric efficiency. This study provides insights into the benefits of modulator-based tuning of porosity within monolithic ZIFs which, combined with their hydrophobicity, may facilitate their application for industrial organic vapor recovery or indoor air cleaning, where efficient hydrophobic adsorbents which can operate in humid environments are essential.

Journal article

Cherukupally P, Sun W, Wong APY, Williams DR, Ozin GA, Bilton AM, Park CBet al., 2019, Surface-engineered sponges for recovery of crude oil microdroplets from wastewater, Nature Sustainability, ISSN: 2398-9629

In the United States, the oil industry produces over 15 billion barrels of wastewater contaminated with crude oil microdroplets annually. Current methods are ineffective for the removal of these microdroplets at the variable pH conditions commonly found in wastewater. Here, an innovative surface-engineered sponge (SEnS) that synergistically combines surface chemistry, charge and roughness, provides a solution to this problem. Over broad pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95–99% removal efficiency, predominantly facilitated by Lifshitz–van der Waals forces. At the optimum pH, 92% of the oil was adsorbed within 10 min. The oil was subsequently recovered by solvent extraction under ambient conditions, and the cleaned SEnS was reused for oil microdroplets adsorption ten times. The combined efficacy and reusability can enable large-scale removal and recovery of crude oil microdroplets from wastewater.

Journal article

Hakim Mohd Azmi L, Williams DR, Ladewig BP, 2019, Can Metal Organic Frameworks Outperform Adsorptive Removal of Harmful Phenolic Compound 2-Chlorophenol by Activated Carbon?, Publisher: American Chemical Society (ACS)

<jats:p>&lt;b&gt;Abstract:&lt;/b&gt; Removal of persistent organic compounds from aqueous solutions is generally achieved using adsorbent like activated carbon (AC) but it suffers from limited adsorption capacity due to low surface area. This paper describes a pioneering work on the adsorption of an organic pollutant, 2-chlorophenol (2-CP) by two MOFs with high surface area and water stability; MIL-101 and its amino-derivative, MIL-101-NH&lt;sub&gt;2&lt;/sub&gt;. Although MOFs have higher surface area than AC, the latter was proven better having the highest equilibrium 2-CP uptake (345 mg.g&lt;sup&gt;-1&lt;/sup&gt;), followed by MIL-101 (121 mg.g&lt;sup&gt;-1&lt;/sup&gt;) and MIL-101-NH&lt;sub&gt;2&lt;/sub&gt; (84 mg.g&lt;sup&gt;-1&lt;/sup&gt;). Used MIL-101 could be easily regenerated multiple times by washing with ethanol and even showed improved adsorption capacity after each washing cycle. These results can open the doors to meticulous adsorbent selection for treating 2-CP-contaminated water</jats:p>

Working paper

Cherukupally P, Sun W, Wong APY, Williams DR, Ozin GA, Bilton AM, Park Cet al., 2019, Adsorptive Recovery of Crude Oil Microdroplets from Wastewater Using Surface Engineered Sponges

<jats:p>In the US, the oil industry produces over 15 billion barrels of wastewater contaminated with crude oil microdroplets annually. Current technologies are unable to remove these microdroplets at different pH conditions. Herein, an innovative surface engineered sponge (SenS) was designed by combining surface chemistry, surface charge, roughness, and surface energy. Under all pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95-99% removal efficiency. The adsorbed oil was recovered at ambient conditions while the cleaned SEnS was reused for five times for crude oil adsorption. Due to the process efficacy, sponge reuse, and oil recovery, this adsorptive-recovery method using SEnS demonstrates great potential for the industrial recovery of oil from wastewater.</jats:p>

Journal article

Duralliu A, Matejtschuk P, Williams DR, 2019, Measuring the specific surface area (SSA) of freeze-dried biologics using inverse gas chromatography, EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, Vol: 142, Pages: 216-221, ISSN: 0939-6411

Journal article

Hedberg SHM, Brown LG, Meghdadi A, Williams DRet al., 2019, Improved adsorption reactions, kinetics and stability for model and therapeutic proteins immobilised on affinity resins, Adsorption, Vol: 25, Pages: 1177-1190, ISSN: 0929-5607

Protein adsorption on solid state media is important for the industrial affinity chromatography of biotherapeutics and for preparing materials for self-interaction chromatography where fundamental protein solution thermodynamic properties are measured. The adsorption of three model proteins (lysozyme, catalase and BSA) and two antibodies (a monoclonal and a polyclonal antibody) have been investigated on commercial affinity chromatography media with different surface functionalities (Formyl, Tresyl and Amino). Both the extent of protein immobilised (mg protein/ml media) and the reaction kinetics are reported for a range of reaction conditions, including pH, differing buffers as well as the presence of secondary reactants (glutaraldehyde, sodium cyanoborohydride, EDC and NHS). Compared to the reaction conditions recommended by manufacturers as well as those reported in previous published work, significant increases in the extent of protein immobilisation and reaction kinetics are reported here. The addition of glutaraldehyde or sodium cyanoborohydride was found to be especially effective even when not directly needed for the adsorption to happen. For mAb and pIgG, immobilisation levels of 50 and 31 mg of protein/ml of resin respectively were achieved, which are 100% or more than previously reported. Enhanced levels were achieved for lysozyme of 120 mg/ml with very rapid reaction kinetics (< 1 h) with sodium cyanoborohydride. It can be concluded that specific chromatography resins with Tresyl activated support offered enhanced levels of protein immobilisation due to their ability to react to form amine or thio-ether linkages with proteins. Additionally, glutaraldehyde can result in higher immobilisation levels whilst it can also accelerate immobilisation reaction kinetics.

Journal article

Duralliu A, Matejtschuk P, Dubey S, Koroma H, Gubinelli F, Williams DRet al., 2019, The influence of the closure format on the storage stability and moisture content of freeze-dried influenza antigen, VACCINE, Vol: 37, Pages: 4485-4490, ISSN: 0264-410X

Journal article

Antonio Zarate J, Sanchez-Gonzalez E, Williams DR, Gonzalez-Zamora E, Martis V, Martinez A, Balmaseda J, Maurin G, Ibarra IAet al., 2019, High and energy-efficient reversible SO2 uptake by a robust Sc(III)-based MOF, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 7, Pages: 15580-15584, ISSN: 2050-7488

Journal article

Ngeow YW, Chapman AV, Heng JYY, Williams DR, Mathys S, Hull CDet al., 2019, Characterization of silica modified with silanes by using thermogravimetric analysis combined with infrared detection, Rubber Chemistry and Technology, Vol: 92, Pages: 237-262, ISSN: 0035-9475

Tire treads with reduced rolling resistance and increased wet grip can be achieved by coupling hydrophilic silica to hydrocarbon rubber by using an alkoxysilane. The silica surface was modified by reaction with a wide range of coupling and non-coupling silanes. The chemistry and extent of these silanizations were elucidated using thermogravimetric analysis (TGA) combined with infrared detection. The silane grafting efficiencies were typically 52–72%, but efficiencies were lower in the bulkier [3-(di-(tridecyloxypenta(ethyleneoxy))ethoxysilyl]propyl mercaptan. However, the silica surface coverage increases with increasing size of the silane. Grafting efficiencies were lower with higher silane loadings. In the TGA, ethoxy and methoxy groups are displaced from the grafted silanes mainly at moderate temperatures (up to about 495 °C) to form siloxane bridges. Over a similar temperature range, the weaker S–S bonds present in bis(3-triethoxysilylpropyl) tetrasulfide (TESPT)- or bis[3-(triethoxysilyl)propyl] disulfide (TESPD)-modified silica are cleaved, leading to weight losses from TESPT or TESPD bound at one end to the silica and from TESPT bound at both ends. The remaining weight losses from bound silanes occurred mainly at higher temperatures. In the commercial silanized silica Coupsil 8113, TGA indicates that about two of three ethoxy groups in each triethoxysilane were lost during the silanization process.

Journal article

Kondor A, Mautner A, Lee K-Y, Bismarck A, Williams Det al., 2019, Challenges on specific surface area analysis of cellulosic materials, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Ngeow YW, Heng JYY, Williams DR, Davies RT, Lawrence KME, Chapman AVet al., 2019, TEM observation of silane coupling agent in silica-filled rubber tyre compound, Journal of Rubber Research, Vol: 22, Pages: 1-12, ISSN: 1511-1768

The microdispersion of silica in filled elastomer vulcanisates was evaluated by transmission electron microscopy (TEM)—network visualisation analysis. In this study, the silica is modified with a wide range of coupling and non-coupling silanes. The silica-filled elastomer samples were microtomed using a glass knife. The resulting TEM micrographs were interpreted and characterised based on aggregates with a cross-sectional area larger than 100 nm2. The study showed that silica surface modification has reduced the silica aggregate size by approximately 30–40% compared to an untreated silica-filled elastomer vulcanisate. The TEM micrographs showed evidence of coupling between silica and the elastomer phase and demonstrated a good estimation of silica microdispersion in the elastomer phase. This study has shown that the presence of different surface functionalities has an effect on the silica microdispersion.

Journal article

Hedberg SHM, Devi S, Duralliu A, Williams DRet al., 2019, Mechanical behavior and structure of freeze-dried cakes, Methods in Pharmacology and Toxicology, Pages: 327-351

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Freeze-drying or the lyophilization of biopharmaceuticals is a standard method for product manufacture in order to increase product shelf-life and minimize the tendency of re-constituted products to aggregate. However, the physical and or mechanical stability of freeze-dried cakes can be problematic, which can directly result in financial losses due to unusable or damaged products. Currently, there is very limited systematic knowledge of the relationship between lyophilization process conditions and the cake-specific physical structure, mechanical performance, and stability. This Chapter reviews the detailed mechanical properties and structure of freeze-dried cakes formed from aqueous solutions with concentrations from 1 to 40% w/v of common excipients, mannitol, sucrose, and trehalose in some detail. In addition, the mechanical properties of commercial freeze-dried products as well as effects of moisture content and ingress into freeze-dried cakes are also reported. Both experimentally measured Young’s moduli and yield stress data scale well with reduced cake density, in line with theoretical predictions from classical cellular solids theory. A novel compressive indentation method is reviewed which can accurately determine a cake’s Young’s modulus and yield stress within 1 min, allowing the potential future use of these mechanical cake attributes as Critical Quality Attributes (CQAs).

Book chapter

Hedberg S, Rapley J, Haigh JM, Williams Det al., 2018, Cross-interaction chromatography as a rapid screening technique to identify the stability of new antibody therapeutics, European Journal of Pharmaceutics and Biopharmaceutics, Vol: 133, Pages: 131-137, ISSN: 0939-6411

Protein aggregation can be a major problem in the manufacturing of new biopharmaceuticals and there is a desirability for development of techniques that can predict the behaviour of new biopharmaceuticals early on in the development process. A technique that can be used to predict aggregation is self-interaction chromatography that is used to determine the second virial coefficient, B22, but one of the limitations includes the need to immobilise every protein of interest. In this study a related technique, cross interaction chromatography (CIC), is evaluated which overcomes this limitation. Three antibodies were studied across a range of NaCl concentrations with each antibody being studied as both a mobile phase and as the stationary phase - in total 6 different stationary-mobile phase combinations. The B22 values obtained for all three proteins correlated strongly with the B23 results obtained for the same protein in the mobile phase, and were significantly independent of the protein immobilised on the stationary phase. This observation allows the use of pre-prepared columns with known immobilised model proteins such as a polyclonal antibody or mAb, with other unknown monoclonal antibodies in the mobile phase. Preliminary experiments using a series of known immobilised mAbs columns with an unknown mAb in the mobile phase resulted in at least a 50 fold reduction in the amount of unknown protein needed and a rapid semi-quantitative assessment of aggregation propensity. CIC can speed up the screening process with minimum preparation time and therefore more rapidly be able to identify the aggregation stability of new antibody formulations.

Journal article

Sadeek SA, Williams DR, Campbell KLS, 2018, Using sodium thiosulphate for carbon steel corrosion protection against monoethanolamine and 2-amino-2-methyl-1-propanol, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 78, Pages: 125-134, ISSN: 1750-5836

Journal article

Ali N, Marsh J, Godfrey S, Williams DRet al., 2018, Aqueous MEA and Ammonia Sorption-Induced Damage in Keratin Fibers, ACS OMEGA, Vol: 3, Pages: 14173-14180, ISSN: 2470-1343

Journal article

Sadeek SA, Williams DR, Campbell KLS, 2018, Using sodium thiosulphate for carbon steel corrosion protection against monoethanolamine and methyldiethanolamine, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 74, Pages: 206-218, ISSN: 1750-5836

Journal article

Williams DR, 2018, Mapping the mAb Aggregation Propensity Using Self-InteractionChromatography as a Screening Tool, Analytical Chemistry, ISSN: 0003-2700

Journal article

Duralliu A, Matejtschuk P, Williams DR, 2018, Humidity Induced Collapse in Freeze Dried Cakes: A Direct Visualization Study using DVS., European Journal of Pharmaceutics and Biopharmaceutics, Vol: 127, Pages: 29-36, ISSN: 0939-6411

Maintaining low moisture content is seen as crucial to sustaining long term stability in freeze dried (FD) cakes as higher moisture could lead to cake collapse, degradation and loss in biological potency. Using a combination of gravimetric data and video images captured from a Dynamic Vapour Sorption instrument the onset humidity Collapse Point (RHcp), the humidity Onset Crystallisation (RHc) and Onset Glass Transition (RHg) points for a series of freeze dried cakes at 10, 25 and 40°C have been determined. The moisture sorption behavior with respect to cake collapse and other morphological phase transitions are reported for a two freeze drying excipients and one product formulation; sucrose, trehalose (both 5% w/w) and an influenza antigen (A/Wisconsin/15/2009 H3N2 NYMCX-183, formulated with 1.1% w/w sucrose). Stability maps for all three formulations tested were reported as a function of %RH and temperature using the methods described in this work, thus direct visualization of collapse behavior for any FD cake can now be standardized and routinely determined, facilitating the formulation of FD products with improved stability and storage performance.

Journal article

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