Abstract submission is now open
We would like to offer the opportunity to submit papers for this conference in the general field of particle engineering. Areas to be considered include modellling, particle formation and measurement. Authors of successful abstracts will be offered the opportunity to present an oral paper on the topic. There will also be ample opportunities to present work in the form of posters.
Abstracts should consist of a one- paragraph summary (ca 150 – 200 words) and the contact details of the authors and a contact address.
Please use the abstract template [download document]
Predictions, Crystals and Crystallisations
Prof. Alastair Florence
University of Strathclyde
Crystallisation is widely used in the purification and production of pharmaceuticals and other fine chemicals however our fundamental understanding of the transformations involved remains limited. As a consequence, solid form selection and process development remains highly dependent upon extensive experimental effort to identify potential crystal forms, measure properties and stability and to select process conditions that enable uniform product to be achieved. The presentation will cover elements where predictive tools can impact through targeting experiment towards desirable outcomes. Examples will include the role of crystal structure prediction as a tool to inform experimental approaches for the discovery of novel polymorphs and also show the potential role of statistical models to understand crystallisability and solid state diversity.
Crystal Engineering: From Form to Function
Prof. Michael Zaworotko
That composition and structure profoundly impact the properties of crystalline solids has provided impetus for exponential growth in the field of crystal engineering1 over the past 25 years. This lecture will address how crystal engineering has evolved from structure design (form) to control over bulk properties (function). Strategies for the generation of two classes of functional crystalline materials will be delineated: Multicomponent pharmaceutical materials, MPMs, such as cocrystals2 have emerged at the preformulation stage of drug development. This results from their modular and designable nature which facilitates the discovery of new crystal forms of active pharmaceutical ingredients, APIs, with changed physicochemical properties. Case studies concerning hydrates and brain bioavailability of lithium will be presented. Hybrid Ultramicroporous Materials, HUMs, are built from metal or metal cluster “nodes” and combinations of organic and inorganic “linkers”. Benchmark selectivity for CO2 capture in HUMs with pcu or mmo topology has been observed3 thanks to the strong electrostatics associated with pores lined by the inorganic components of these nets. New results that address other applications of HUMs will be presented.
In summary, this lecture will emphasize how crystal engineering, especially when coupled with molecular modeling, can offer a paradigm shift from the more random, high-throughput methods that have traditionally been utilized in materials discovery and development.
1. (a) Desiraju, G.R. Crystal engineering: The design of organic solids Elsevier, 1989; (b) Moulton, B.; Zaworotko, M.J. Chemical Reviews 2001, 101, 1629-1658.
2. Duggirala, N.; Perry, M.L.; Almarsson, Ö.; Zaworotko, M.J. Chem. Commun. 52, 640-655, 2016.
3. Nugent, P.; Belmabkhout, Y.; Burd, S.D.; Cairns, A.J.; Luebke, R.; Forrest, K.; Pham, T.; Ma, S.; Space, B.; Wojtas, L.; Eddaoudi, M.; Zaworotko, M.J. Nature 2013, 495, 80-84, 2013.
Designed particles for optimised formulations using supercritical fluid technologies
Prof. Peter York
Design of efficient and effective solid particles in formulation science depends upon two fundamental principles – a well understood, controlled, flexible particle formation process and clearly defined target particle properties and performance characteristics. Whilst there are numerous claims made to be able to achieve such particle design, in practice real particle design strategies and processes based on the above criteria are rather limited. Our extensive materials, science and engineering research and development studies, together with evidence from client and in-house projects, has clearly demonstrated the success and superior performance of supercritical fluid (SCF) particle formation technologies. This applies to a wide variety of chemicals primarily used in formulations and products for the pharma, biotech, agrochem, and healthcare sectors.
This presentation introduces the concept of the key requirements for efficient and effective particle design and briefly highlights the scientific and engineering background to the modified supercritical anti-solvent (mod-SAS) technology. A number of examples of single component and multi-component (i.e. formulated) particle designs are then provided, ranging from consideration of solid state and physical properties and improving the bioavailability of solubility limited drugs, through to in vivo evidence for designed particles within final manufactured medicines achieving defined target particle and product performance criteria. The presentation provides an update on more recent applications of SCF to especially challenging molecules. Benefits of this strategy relating to current QbD philosophy and regulatory ambition are also considered.
The presentation concludes with a brief summary and a forward look for the wider uptake and application of SCF-based particle design strategies.
Can the crystal structure of organic molecules be predicted?
Dr John Kendrick
University of Bradford
The “Blind Tests in Crystal Structure Prediction” organised by the Cambridge Crystallographic Data Centre (CCDC) provide a very useful benchmark for the progress that is being made in our ability to predict a crystal form simply on the basis of the molecular structure of a molecule. The talk will provide a survey of the results that have been achieved in the Blind Tests, culminating in the last test which reported its results in 2015 and which has been submitted for publication. An outline of the methods employed will be described and a summary given of the potential applications of methods which can successfully predict crystal structure. The talk will conclude by a brief look at the future for crystal structure prediction.
Salt-Cocrystal interface studies: The importance of being Hydrogen
Prof. Chris Frampton
Wolfson Centre for Materials Processing, Brunel University
The physical properties of many functional industrial materials including that of active pharmaceutical ingredients are dependant upon the crystal structure of that material. Along with polymorph screening and salt selection, the area of cocrystallisation offers a further unique and exciting opportunity in the area of solid form development to enhance or change deficient properties that may be inherent within a particular development candidate, e.g. hygroscopicity, melting point, dissolution rate and processability by modification of the crystal structure. The presentation will focus in particular on the transition pathway of salt to cocrystal from a structural perspective as illustrated below for the case of the weakly basic agrochemical active Pyrimethanil.
The pka of a coformer can have a significant influence on the structural outcome yielding in some cases multiphase materials where a salt and a cocrystal of the same active material and coformer can coexist either in the same asymmetric unit of the crystal structure or a further example where they can be isolated as unique materials from the same crystallization experiment.
Drug product design: From molecule to drug product
Dr Ernest Chow
In Drug Product Design at Pfizer, our vision is that “Molecules make crystals, crystals make particles, and particles make drug products“. As we ask ourselves why drug products behave the way they do, we constantly aim to better understand the link from the fundamental chemistry of the molecule to drug product performance.
In this presentation, we would like to take you through our current journey from molecules to drug products. We have been constantly making progress through collaboration with the academic community, together with the implementation of new characterisation techniques and computational modelling tools. The importance of surface chemistry, surface anisotropy, and crystal morphology will be discussed, which are important building blocks that allow our knowledge on solid form to be extended into predicting crystal or particle properties.
There’s still a long way ahead towards our ultimate goal, which is to be able to rationally design drug products of desired properties from first principles. With our continued efforts, we are eager to explore the path in front of us, and we welcome any further engagement from the scientific community to join us on our journey from molecules to drug products.
Functional Group Interactions and Cocrystal Formation
Prof. Chris Hunter
University of Cambridge
Molecular recognition events in solution and the solid state are affected by many different factors that complicate the development of a thermodynamic understanding of intermolecular interactions at the quantitative level. We have developed an integrated approach for estimating the relative magnitudes of non-covalent interactions in different environments. This presentation will describe the application of these ideas to the solid state, and specifically to the problem of the prediction of the probability of cocrystal formation between two different substances.
Crystallisation – a matter of patience
Dr Sophie Janbon
The pharmaceutical industry uses crystallisation primarily as a mean to purify and isolate desired organic chemical molecules from solutions1. Crystallisation is a two-step process in which supersaturation drives molecules from solution into nuclei, some of which reach a critical size, after which crystal growth occurs2.
Molecules vary in flexibility, size, shape and functional groups. Unsurprisingly, the kinetics of crystal nucleation and growth vary from molecule to molecule. Moreover, most molecules can access more than one crystal structure. This phenomenon of polymorphism is particularly important for Active Pharmaceutical Ingredients (APIs) as different polymorphs may have different bioavailabilities. Consistent API particle properties are also required for consistent downstream processing and dissolution.
Regardless of molecular design, the same procedure is used to develop crystallisation processes. The first step is to identify a suitable solvent system, which is best done via solubility measurements. This fixes the yield and productivity of the crystallisation process.
The next step is to define a ‘safe space’ in terms of seeding, cooling rates and other parameters to achieve the desired Critical Quality Attributes (CQAs), including polymorph and particle properties. Such experiments can be performed in the laboratory at a scale of few millilitres. The final step is to evaluate the effects of scale-up to hundreds of litres, paying particular attention to effects on particle properties.
This presentation will show how to develop different types of crystallisation processes, including real examples from the pharmaceutical industry, which illustrate typical challenges.
1 R. Davey & J. Garside. From Molecules to Crystallisers: An introduction to Crystallization, Oxford Chemistry Primers, 2001.
2 J. W. Mullin, Crystallization, Elsevier Ltd, Fourth Edition, 2001
Silicon-based Aerocrystals for controlled delivery of very high payloads of Nanostructured drugs
Dr Leigh Canham
Figure 1. A silicon “aerocrystal”.
Mesoporous matrices are receiving increasing attention for drug delivery (1). The very small size of mesopores (2-50nm) results in nanostructured loaded drugs. Required matrix properties include biocompatibility and excellent control of morphology. The latter is used to tune the delivery of therapeutic levels of the drug, either by restricted diffusion via mesopores, or biodegradability, or a combination of the two.
One key performance parameter is the drug payload, since this determines how much material needs to be administered to achieve therapeutic drug levels. We demonstrate that it is feasible to achieve very high payloads using silicon-based “aerocrystals” (see figure 1) prepared by a combination of electrochemical etching techniques and supercritical drying (2). Internal payloads of a model drug (ibuprofen) are assessed by a combination of 4 analytical methods and demonstrate that 70wt% (drug/(drug + matrix) ) nanostructured drug loading is achievable. We believe this value is the highest internal payload reported to date for any mesoporous matrix-based delivery system, surpassed only by reservoir systems.
1. Mesoporous Biomaterials: A New Open Access Journal. www.degruyter.com/view/j/mesbi
2. Luminescent anodized silicon aerocrystal networks prepared by supercritical drying. L.T.Canham, A.G.Cullis, C.Pickering, O.D.Dosser, T.I.Cox, T.P.Lynch. Nature 368: 133-5 (1994)
Abstracts for Posters Presentations
Preparation Of Polycaprolactone Nanoparticles Via Supercritical Carbon-dioxide Extraction Of Emulsions
Adejumoke Lara Ajiboye* a, Vivek Trivedi a, *, and John Mitchell a
a University of Greenwich, Central Avenue, Chatham Maritime. Kent. ME4 4TB
The use of drug delivery systems, particularly the micro- and nano- scale intelligent systems for therapeutic molecules has rapidly increased over the years because they can successfully maximise the efficacy of the drug molecules. This has therefore led to an increase in the use of biodegradable polymers such as polycaprolactone (PCL) for the production of nanoparticles1. Common nanoparticle preparation methods are usually associated with limitations concerning process efficiency and control of the particle size and distribution1. In this work, PCL nanoparticles were produced through oil-phase extraction of an oil-in-water emulsion via supercritical fluid (SCF) processing. The efficiency of the supercritical carbon dioxide extraction was investigated and compared to that of solvent extraction at atmospheric pressure. The effects of process parameters including polymer concentration and polymer: surfactant ratio on the particle size and surface morphology were also investigated. Spherical polycaprolactone nanoparticles with mean particle sizes between 190 – 350 nm and of a uniform size distribution were produced. Nanoparticles produced were analysed using dynamic light scattering and scanning electron microscopy.
Table: Size distribution of PCL nanoparticles.
Figure 1: Micrograph of PCL nanoparticles.
SCF extraction of emulsions allowed the preparation of PCL nanoparticles without agglomeration and in a comparatively short duration. These particles have the potential to be used as delivery vehicles either by surface adsorption of a drug or encapsulation within to provide modified release1.
 M.R. Guilherme et al, Polycaprolactone nanoparticles containing encapsulated progesterone prepared using a scCO2 emulsion drying technique, Materials letters 124 (2014) 197-200.
Solubility and Intrinsic Dissolution Rate Study for Caffeine:Dicarboxylic acids Cocrystals
MHD Bashir Alsirawan, Dr. Venu R. Vangala, Prof. Anant Paradkar
Centre for Pharmaceutical Engineering Science – University of Bradford
Cocrystals have a promising potential for pharmaceutical industry due to their role in improving physicochemical properties such as solubility, bioavailability, and stability. Caffeine (CA):Dicarboxylic acids (DAs) cocrystals shown to display superior physical stability compared to caffeine. The objective of this paper is to perform solubility and IDR measurements of CA cocrystals with various coformers namely, oxalic (OX), malonic (MO), glutaric (GL), and maleic acid (ML) and compared the results to that of pure CA. The chosen cocrystals are CA:OX2:1, CA:MO2:1, CA:GL 1:1(FII) CA:GL 1:1(FI), CA:ML1:1, and CA:ML2:1. The results suggest that CA:OX exhibited lower solubility (12.5 mg/mL) and IDR (3.54 mg min-1 cm-2) compared to pure CA (20.32 mg/mL and 5.13 mg min-1 cm-2). CA:MO IS (30.2 mg/mL) is higher compared to CA but have IDR (3.76 mg min-1 cm-2) lower than CA. Both CA:GL(FII) and CA:ML1:1, have showed significantly higher solubility (60.4 and 58.8 mg/mL) and IDR ( 21.37 and 22.52 mg min-1 cm-2). In conclusion, cocrystal technology can offer an opportunity to obtain different solubility and dissolution profiles. However, a balance of stability and solubility should be taken into consideration during the drug development.
Solubility and crystallization of pharmaceutical drugs in an ionic liquid system
Ratnadeep Bansode, Nazira Karodia, Anant Paradkar
University of Bradford
Ionic liquids, commonly defined as salts that melt below 100 °C, Ionic liquids have proven their applications in due to their unique tuneable properties, and due to their thermal stability. The present work is a systematic study on the solubility of sulfathiazole drug in ionic liquids. This work is focused on screening of three ionic liquids as alternative function solvents, 1-ethyl-3-methylimidazolium tetrafluroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium diethyl phosphate used for the cooling and antisolvent crystallization of a Sulfathiazole. Sulfathiazole tested were soluble 50 °C, 70 °C and 100 °C within ionic liquids. The cooling and antisolvent crystallizations were carried out above ionic liquids and were found to produce sulfathiazole. A dramatic effect was ascribed to the solubility of sulfathiazole in 1-ethyl-3-methylimidazolium tetrafluroborate ionic liquid. In conclusion the studied ionic liquids are appropriate solvents for drug manufacturing and such solvents can be suitable for pharmaceutical processing. PXRD analysis showed that mixtures of three different polymorphs were obtained and DSC analysis showed that new melting point of sulfathiazole compared to other polymorphs.
Thermodynamic investigation of carbamazepine-saccharin co-crystal polymorphs
Niten B Jadav, Sudhir Pagire, Venu Vangala, Benjamin Whiteside and Anant Paradkar
University of Bradford
Polymorphism in active pharmaceutical ingredients (APIs) can be regarded critical for the potential that crystal form can have on the quality, efficacy and safety of the final drug product. The current contribution aims to characterize thermodynamic interrelationship of a dimorphic co-crystal, FI and FII, involving carbamazepine (CBZ) and saccharin (SAC) molecules. Supramolecular synthesis of CBZ-SAC FI and FII have been performed using thermo-kinetic methods and systematically characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and solubility and slurry measurements. According to Berger and Ramberger’s heat of fusion rule, FI (∆Hfus = 118.7 J/g, mp 171.5 °C) and FII (∆Hfus= 110.3 J/g, mp 164.7 °C) are monotropically related. The solubility and van’t Hoff plot results suggest that FI stable and FII metastable forms and these are monotropically related polymorphs. This study reveals that CBZ-SAC co-crystal phases, FI or FII, could be stable to heat induced stresses during formulation development. It should be mentioned, however, that FII converts to FI during solution mediated transformation.
Effect of Leucine on aerosolization performance of salbutamol sulphate containing spray dried lactose
Carlos Molina and Ali Nokhodchi
University of Sussex
Through the use of spray drying, which allows for the manipulation of a particle’s physicochemical properties along with their morphology, L-Leucine was introduced into lactose monohydrate formulations of varying concentrations (0.1%, 0.5%, 1%, 5%, and 10%; w/w) and then compared to physical mixtures of similar concentrations to determine aerosolization performance of salbutamol sulphate. To analyze each formulation, numerous analytical techniques were implemented such as particle size distribution analysis, Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), Powder X-Ray Diffraction (PXRD), and Fourier Transform Infrared (FT-IR) Spectroscopy. The results showed that spray dried samples containing leucine exhibited better aerosolization performance with an increase in fine particle fraction compared to physical mixtures and spray dried sample without leucine. Such effect is attributed to leucine improving surface activity and altering the charge density of lactose particles. In addition, the ease by which lactose monohydrate agglomerates was used, and exploited, in such a manner as to manifest it into a carrier through the careful manipulation of spray drying parameters which altered the aforementioned physicochemical properties.
Encapsulation of ibuprofen in layered hydroxide silicates (Veegum F®)
Uttom Nandi, Vivek Trivedi
University of Greenwich
The desire to maximise therapeutic activity and stability of a drug molecule with minimal side effects has become an important aspect of pharmaceutical drug delivery systems. Novel drug delivery systems based on inorganic clay materials or clay based drug delivery system are currently gaining interest within the pharmaceutical community. Layered hydroxide silica specifically smectite clays are negatively charged particles which are especially adept at retaining positively charged molecules. The layered silicates are known to accommodate polar organic compounds between the layers to form intercalated composites. Present study involves encapsulation of Ibuprofen in a commercial smectite clay (Veegum F®). The clay-drug intercalated composites showed a high drug loading of 80% according to HPLC. The interaction between these two entities also significantly increased the basal spacing of layered silicates from 12.08 to 15.60 Å. Similarly, energy dispersive X-ray spectroscopy (EDX) showed an increase in carbon content by 9% on clay containing Ibuprofen in comparison to the blank clay particles. Considering Carbon as a signature molecule for identification of drugs inside the composites, EDX spectroscopy confirms the encapsulation process of Ibuprofen inside the interlayer spacing of clay particle.
Scale up of production of theophylline cocrystals via continuous hot-melt extrusion
Steven Ross, Dennis Douroumis
Faculty of Engineering and Science, University of Greenwich, Medway Campus,
Difficulties in large-scale production of pharmaceutical cocrystals are a major barrier preventing widespread commercial utilization. Previous typically used methods of cocrystallization, such as solution growth or milling techniques are limited in the scale-up of operation due to the volume of solution required for large-scale production and the fact they are batch controlled operations. This issue can be avoided through the use of hot-melt extrusion (HME). The geometric similarities between mid-size and large scale HMEs enable rapid process scale-up without compromising product quality and because it is a continuous mechanism one can easily redesign the process parameters to increase throughput, while maintaining acceptable quality. In this study; Theophylline (THL) and nicotinamide (NIC) cocrystals were used as a model drug to investigate the effect of HMEs process parameters in the scale-up of production. THL/NIC cocrystals were produced at 0.5kg/hr at various temperatures and screw speeds. Cocrystal quality was evaluated using DSC, XRPD and NIR techniques to find the optimal processing parameters. The process was then scaled up to 1.5kg/hr under optimal conditions with subsequent characterization showing there to be minimal change in cocrystal quality. Only screw speed was adjusted to accommodate the increased throughput. This study has shown that the scale-up of pharmaceutical Cocrystals can be easily achieved through HME, without sacrificing Cocrystal quality, with minimal editing of process parameters.
Silicon-based Aerocrystals for controlled delivery of very high payloads of Nanostructured drugs
Dr Leigh Canham