Complex ORAL health products (CORAL): Characterisation, modelling and manufacturing challenges

Lead Research Organisation: University College London
Department Name: Chemical Engineering

Abstract

Toothpastes - and especially specialised pharmaceutical toothpastes, whose major gel component is not water-based - have a surprisingly complex and ill-understood manufacturing process. There is the background fluid, which is already a mixture of a viscous liquid and a polymer; then solid particles are added. These are abrasive and do much of the tooth cleaning; but they also swell during processing, and the system becomes much thicker when they are added. Finally surfactant is added to help the toothpaste to foam in the mouth; and just to complicate matters further, air bubbles also creep in during processing.

In this project, we will systematically address all the stages of toothpaste processing. We will carry out precise small-scale rheological measurements to discover how the particles swell and how they interact once they have swollen: for example, do they absorb parts of the long polymer molecules to form a network, or do partly-absorbed polymers act as "brushes" to push swollen particles apart? We will also measure the overall behaviour of each stage of the system (the background fluid on its own, or with particles, or with bubbles) and create a phase map of system behaviour in terms of its composition. We will use advanced mathematical modelling techniques to derive new equations that can describe the behaviour of a mixture - for example, background fluid and swollen particles - as if it were a single material. Finally, we will use our new constitutive equations in computer simulations to predict the behaviour of the paste in a real processing environment, address the manufacturing challenges such novel formulations entail and propose new strategies to overcome these.

The research needs a team with many different specialist abilities, across experimentation, modelling and simulation, and also needs close ties with industry to ensure we are asking the right questions. GSK is a major collaborator on this project. The project is also supported by Xaar the leader in inkjet printing technology. With the understanding we generate, they hope to make their manufacturing processes both more efficient and more reliable and also develop new formulations to address future customer needs.

Planned Impact

The proposed research aims to provide new fundamental insights into complex oral health formulations and to overcome the related high impact manufacturing challenges through a multidisciplinary approach encompassing cutting-edge experimental techniques, mathematical modeling and simulations, spanning from the micro to the macro scale domain. It attempts to connect microscopic and macroscopic behaviour of such formulations, address the process scale-up challenges, the issues of manufacturability in current batch processes, and propose innovative solutions to enable new continuous-flow intensified technology.

The project is fully aligned with the EPSRC future formulations and complex fluids agenda and national developments in the field (e.g. National Formulation Centre); it is very much driven by the increased complexity of novel paste formulations in response to customer needs, the lack of understanding this entails in terms of both fundamental science and processing requirements and the need for a generic framework to design, process and manufacture such complex, soft solid formulations for a variety of applications. The strong engagement of a major healthcare industry (GSK) and a leading inkjet company (Xaar) demonstrate the potential for translation and impact that the research can create with industry through optimization of current formulations and production processes, and development of new formulations and manufacturing technologies, encompassing a move to continuous processing with a more reliable and adaptable process protocol. Continuous processing allows better control, uniform conditions, reduced process time and leads to enhanced energy efficiency, reduced wastage and improved product quality. This will advance the manufacturing capabilities of the partner and other related industries with subsequent benefits to the UK economy. The oral health industry is worth £1 billion in the UK with current growth at 4%; the 3D printing and additive manufacturing technology industry are predicted to have a worldwide size of US$16.8 billion by 2018.

Any improvement in toothpaste manufacture comes with major societal impact, as oral health is critical to overall health, particularly in childhood: dental caries is the number one reason why children aged five to nine are admitted to hospital in England. Toothpastes are the most important and widely used oral care products and many modern ones have pharmaceutical properties such as enamel rebuilding. Our research will help to address manufacturing issues of modern non-aqueous toothpastes and will lead to better control of the product properties which will impact on function and user acceptance.

The project is multidisciplinary with many novel aspects that will advance the science and technologies underpinning the formulation of complex pastes. This knowledge will be passed down to university students through teaching and project work, inspiring the next generation of scientists and engineers. Most notably, the project will result in highly trained and skilled researchers. The substantial sharing of knowledge and techniques between the experimental and modeling streams of the project, and the close interaction with industry will result in the research staff employed in the project acquiring unique skills and knowledge in cutting edge research techniques and scientific concepts in complex fluids and process engineering. This skillset is of extreme importance in manufacturing the future, and will not only enhance future career prospects of the researchers, in either academia or industry, but also benefit the UK's economic growth and competitiveness.

Publications

10 25 50
 
Description in the project we have developed a number of state of the art experimental approaches to study the rheological properties, the flow and the mixing of non-Newtonian fluids and of solid suspensions in non-Newtonian media. These are relevant to the manufacturing of many modern formulations, such as oral care products and toothpastes. In addition, we have developed new analytical and numerical approaches for the modelling of solid suspensions. the combined experimental and numerical approaches have enabled us to study the behaviour of the formulations in different process environments including the current widely used batch vessels but also new continuous systems. In particular for the latter we exploited novel rheological measurements to produce maps of the degree of gelation of the formulations.
Exploitation Route -The findings on the mixing of non-Newtonian fluids in stirred vessels can be used to improve the design of the vessels and to choose appropriate operation conditions.
-The methodology for developing maps for the degree of gelation can be applied to other systems and can aid process design..
-The experimental techniques developed fort the study of flow and mixing of non-Newtonian suspensions are generic and applicable to other systems.
-The simulation tools can be used to model the mixing in different process units of complex formulations which involve suspensions of particles.
Sectors Chemicals,Healthcare,Manufacturing, including Industrial Biotechology

URL https://www.ucl.ac.uk/chemical-engineering/thames-advanced-multiphase-systems
 
Description In the project we are investigating the rheology and the mixing of non-Newtonian fluids relevant to the manufacturing of complex oral healthcare formulations, such as toothpastes. The findings so far, both experimental and numerical, have revealed how mixing progresses in industrial scale units and have led to recommendations to improve the mixing and reduce the time required. We are also considering an alternative continuous manufacturing approach that will improve quality and reduce the time required to produce the formulation. This approach involves initial mixing of two liquid phases followed by gelation . Extensive rheological studies, using a new approach to characterise both the viscous and the elastic properties of the formulations, have resulted in maps which link the degree of gelation to the temperature and the consistency of the mixture. These maps are currently being implemented in the design of the continuous process. Demonstration set ups based on the project and on the manufacturing of toothpastes have been used in STEM open days at University and in talks to schools. Researchers have also given outreach talks to schools and science festivals on the importance of science and engineering in improving quality of life.
First Year Of Impact 2018
Sector Chemicals,Healthcare,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

 
Description Flow Pattern Transitions In Oil-Water Flows - Impact Studentship
Amount £66,000 (GBP)
Organisation Chevron Corporation 
Sector Private
Country United States
Start 09/2018 
End 02/2022
 
Description Industrial project
Amount £138,956 (GBP)
Organisation GlaxoSmithKline (GSK) 
Sector Private
Country Global
Start 04/2018 
End 04/2019
 
Description Mixing in complex oral health products
Amount £33,000 (GBP)
Organisation GlaxoSmithKline (GSK) 
Sector Private
Country Global
Start 09/2016 
End 08/2019
 
Description PREdictive Modelling with QuantIfication of UncERtainty for MultiphasE Systems (PREMIERE)
Amount £6,560,538 (GBP)
Funding ID EP/T000414/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2019 
End 09/2024
 
Description Studies of non-Newtonian suspensions
Amount £85,000 (GBP)
Organisation GlaxoSmithKline (GSK) 
Sector Private
Country Global
Start 08/2019 
End 03/2023
 
Description APS Presentation (Jurriaan) 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Conference presentation by Jurriaan Gillissen (RA on this project) at APS meeting, October 2018. Title "Contact Friction and Normal Stresses in Particle Suspensions".
Year(s) Of Engagement Activity 2018
URL https://www.apsdfd2018.org/
 
Description Conference presentation, UK Fluids Conference 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact PhD student Liam Escott gave a talk entitled "Rheological properties of a solid sphere suspension in second order fluid using a single cell model" at the UK Fluids Conference, primarily a postgraduate student forum.
Year(s) Of Engagement Activity 2018
 
Description Enrichment talk to high school students 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Delivered a 20 minute lecture on an interesting area of applied mathematics which was followed by a 10 mins of Q&A with the students.
Year(s) Of Engagement Activity 2020
 
Description Girls in Maths day (Kent) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Around 60 pupils (all female) attended a day of talks and workshops by various mathematicians. I talked about my research, including this project, which sparked questions and discussion.
Year(s) Of Engagement Activity 2017
 
Description IMA 16+ Lecture 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A lecture covering much of my research, including that carried out in this project, to 16-17 year old students.
Year(s) Of Engagement Activity 2018
URL https://mediacentral.ucl.ac.uk/Play/13697
 
Description Inspire Summer School 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact The Inspire Summer School is a residential summer school programme which promotes STEM degrees among young female students. During the three days, the students gained a deeper understanding and hands-on experience on sustainable engineering solutions whilst experiencing university style lectures and receiving sessions on presentation skills, research techniques, safety and ethics in engineering. Specific demonstrations based on project findings (such as efficient mixing of fluids and the effects of rheology) were implemented.
Year(s) Of Engagement Activity 2020
 
Description Maths Gets Messy - outreach talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact This is a talk I give to various different organisations, such as Cafe Scientifique, IMA regional branches, etc. It discussed complex fluids in general but also the specific research produced by the CORAL project. The audience is typically of size about 50, an evening event with age range from teens to nineties. The impact is likely opening people's minds to the ways science and mathematics are used in the commercial world; I don't usually get any direct evidence of this impact.
Year(s) Of Engagement Activity 2017,2018
 
Description New Scientist Instant Expert day 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Day-long series of lectures, with a panel discussion at the end, themed on mathematics. I talked about my research including the CORAL project. Several people were particularly engaged with, and asking questions about, the applications of viscoelastic fluids.
Year(s) Of Engagement Activity 2018
 
Description Oral presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Oral presentation given at the 70th Annual Meeting of the APS Division of Fluid Dynamics ( Sunday-Tuesday, November 19-21, 2017; Denver, Colorado). This is one of the most established conferences in the fluid dynamics community. Title of talk: Effect on Non-Newtonian Rheology on Mixing in Taylor-Couette Flow by N. Cagney, S. Balabani. Abstract can be found in the Bulletin of the American Physical Society, Volume 62, Number 14.
Year(s) Of Engagement Activity 2017
URL http://meetings.aps.org/Meeting/DFD17/Session/L37.2
 
Description Oral presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Annual European Rheology Conference 2018. 17 - 20 April 2018 - Sorrento Italy Title of oral presentation:
'Particles in Complex Formulations: Rheology, Dynamics and Microstructure' A. Papadopoulou, M. K. Tiwari, S. Balabani.
Year(s) Of Engagement Activity 2018
URL https://rheology-esr.org/aerc2018/welcome
 
Description Poster presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact A one day conference organised by the Formulation Science and Technology group (FSTG) of the Royal Society of Chemistry entitled Clever Characterization for Smarter Formulations. Attended by a mixture of academics and industrialists. 10 November 2017 - Burlington House, London - Royal Society of Chemistry
Poster title: 'Understanding the Flow Properties of Particles in Complex Formulations' A. Papadopoulou, M. K. Tiwari and S. Balabani.
Year(s) Of Engagement Activity 2017
URL http://www.rsc.org/events/detail/27809/clever-characterisation-for-smarter-formulation-ii-cc4sf2
 
Description Poster presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation at Annual ChemEng DayUK2018 -Molecules to Manufcatuirng-an annual conference organised by IChemE. Title of poster: 'Rheological Characterisation of suspensions of rough particles in complex formulations ' A. Papadopoulou, M.K.Tiwari and S. Balabani.
Year(s) Of Engagement Activity 2018
URL https://www.chemengdayuk.co.uk
 
Description Presentation to working group with industry 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Broad overview of the current understanding of suspension rheology to an audience of both academics working to improve this understanding, and industrialists using it day to day.
Year(s) Of Engagement Activity 2018
URL https://ifpri.net/
 
Description School visit (London) 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Demonstrated processing steps in the production of toothpastes. A suspension and glycerol were mixed to produce the non Newtonian gel that is used in toothpastes. About 50 students attended the demonstration. This sparked questions on how toothpastes are made and on processing and engineering in general.
Year(s) Of Engagement Activity 2017
 
Description Short Video 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact A video about non- newtonian fluids filmed as part of the UCL Mechanical Engineering: Tomorrow's Technology series. This is a series highlighting connections between everyday phenomena and engineering research, filmed by broadcaster and fellow academic Dr Helen Czerski. Episode 4 features CORAL PhD student Anastasia Papadopoulou using the toothpaste as an exemplar to explain the concept of non-Newtonian Rheology to the wider public. Video appears both in UCL web site as well as YouTube.
Year(s) Of Engagement Activity 2017
URL https://www.youtube.com/watch?v=qRolFxZAw0w&index=4&list=PLXXq6t7B9L_7ItyGo7kzG224AA3QOnpIN
 
Description Study of suspension fluid dynamics in complex oral health products (CORAL) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact More than 50 academics and post graduate students attended the 2nd meeting of Special Interest Groups (SIG), UK Fluids Network in London, 8 December 2017 on the specific topic of : Multiphase Flows and Transport Phenomena. A poster is presented to introduce briefly the current project (CORAL).
Year(s) Of Engagement Activity 2017
URL https://fluids.ac.uk/sig
 
Description Visit by school students 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Students visited the research lab and carried out experiments on rheology measurements and on the use of microfluidics for two phase flow studies. The experiments motivated questions and discussion on non-Newtonian fluids and their applications to modern products. They also prompted further discussions on research and its significance.
Year(s) Of Engagement Activity 2020
 
Description Widening Participation Chemical Engineering Summer School 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact The WP Chemical Engineering Summer School is a residential summer school programme which provides young students coming from underprivileged backgrounds with an understanding of what a career in chemical engineering might entail and which skills are required. Demonstrations based on the project findings were used (e.g. involving rheology, mixing).
Year(s) Of Engagement Activity 2020