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Product Science & Product Evaluation Seminars

09:00 - 09:30

KEYNOTE – Green Chemistry & Cosmetics

Green Chemistry and Cosmetics
The drive for improved sustainability credentials in cosmetics fuelled both by consumer interest and the potential impact of future legislation around, for example micropollutants, is well-known.

Several current topics of research in the field of green chemistry – that is chemistry focussed of the design of products and processes that minimise or eliminate the use and generation of hazardous substances – will be explored.

Solvents
What makes a solvent green? One can consider many aspects. Perhaps a full lifecycle analysis, or a balance of health hazards, whether or not it is bio-based, or biodegradable, whether it gives rise to VOC emissions, or has an aquatic impact,  whether it is flammable or explosive, or otherwise reactive and indeed the impacts those solvent properties may have on the processes in which it is used, or products in which it is a component.

Some existing solvents currently in use in cosmetics will be critiqued - including instances where they have been applied in other fields after cosmetics led the way, and some newer biobased solvents, potentially of relevance to application in cosmetics, will be profiled.

Polymers in Liquid Formulations
Polymers in liquid formulations have an estimated global value of $1.3 trillion pa, with 36 million tonnes being made annually: enough to fill Wembley Stadium 32 times over. As part of an EPSRC/BBSRC Prosperity Partnership collaboration between Croda, the University of Nottingham and the University of York, we have recently been preparing a library of novel bioderived monomers, making those monomers into polymers and are working towards exploring their biodegradability as it is critical that we understand the wider sustainability credentials of these materials and how they might compare with current products.

Peptides
Solid phase peptide synthesis is traditionally highly wasteful - requiring large volumes of undesirable solvent.  We are working to explore both more sustainable solvent choices – and more efficient coupling conditions compatible with those choices.

Speaker

  • Prof. Helen Sneddon Professor in Sustainable Chemistry & Director of the Green Chemistry - University of York
09:30 - 10:00

The Challenges of Delivering Cosmetic Actives – Role of the formulator

The skin has evolved to keep water in and other xenobiotics or foreign substances out. The outer layer, the stratum corneum, is a unique membrane that is about a sixth of the thickness of a piece of paper.  It is composed of dead cells that are filled with keratin and are very dense in nature. Today we understand that it is this thin membrane that is the major barrier to effective targeting of actives from topical formulations.

Targeting of actives to specific regions of the epidermis and dermis is the ‘holy grail’ of skin delivery. However, skin penetration of most actives often does not exceed more than 2-4% of the applied amount. Partly this reflects a lack of focus on the vehicle and a lack of awareness that the fate of the active is linked inextricably to specific carrier components of the formulation. No single formulation can address the competing requirements of the diverse array of compounds we find in personal care and cosmetic products. Instead, consideration must be given to the solubility of the active in vehicle components as well as the residence time of those vehicle components in the skin. The overarching theme of my research is the identification of vehicle components that are optimal for a specific active. Over the years my work has demonstrated the utility of this approach using both in vitro and in vivo studies.

Advances in the range and sensitivity of analytical techniques available to scientists are already providing better insights into vehicle effects on skin delivery of actives. Building on these findings, we should be optimistic about our ability to create better and more efficacious formulations for consumers.

Speaker

  • Majella Lane PhD Director, Skin Research Group - School of Pharmacy, University College London
10:00 - 10:30

Rheological Principles to Predict Sensorial Properties of Topical and Hair Formulations

The sensorial properties of skin and hair care products play a key role on consumer’s acceptability of the products. In a previous work [1] we have set design principles for hand sanitiser formulations relating rheological properties and hand feel experience: low runoff, spreadability, smoothness and non-stickiness. In this work we investigate the rheological properties of different topical and hair care formulations and access if the same design principles can be applied to those formulations.

Shear and extensional rheological measurements were performed on different topical and hair commercial products. Rheological experiments are informative of the deformation and flow behaviour of the material and how it responds to different applied stresses. Shear rheology tells us about the viscoelastic properties of the material when subjected to shear deformations, whereas extensional rheology can show us the material’s response when stretched/extended. Both type of flows can be generated while applying topical and hair care formulations. Steady shear rheology was measured using a Kinexus Ultra+ (NETZSCH), using a 40 mm smooth and/or sandblasted cone-plate 1° geometry, and a 40 mm Crosshatch plate-plate geometry. When possible, the extensional properties of the formulations were obtained using a Capillary Breakup Extensional Rheometer (ThermoFisher) using 6 mm plates.

Results show that not all the topical and hair formulations tested follow all the four design principles proposed in our previous work, which for some products could be expected based on their formulation’s composition. Most of the formulations that passed the smoothness criteria, that is satisfied if the formulation has a measurable First Normal Stress Difference at high shear rates [1], have polymers in their composition. The rheology and sensorial performance of topical formulations can be improved by changing or adjusting the formulation ingredients properties, such as the polymer’s molecular weight and concentration; colloids and particle’s size and concentration; adapting solvent’s composition; and others. A better understanding of the rheological behaviour of formulations and how each ingredient contributes to the final rheological properties of the formulation is key to comprehend product’s behaviour as well as to identify what needs to be modified to achieve enhanced sensorial perception.

 

[1] Silva, A.F., Wood, T.A., Hodgson, D.J.M. et al. Rheological design of thickened alcohol-based hand rubs. Rheol Acta 61, 571–581 (2022)

Speaker

10:30 - 11:00

Coffee & Tea Break

11:00 - 11:30

An Introduction to Nutricosmetics

Discussing the regulatory landscape, claims, and exploring some key considerations in this growing sector.

Speaker

11:30 - 12:00

KEYNOTE – Regulation of Human Skin & Hair Colour: What we know and what we don’t

Melanin synthesis in the human epidermis and hair follicle occurs within melanocyte-specific organelles called melanosomes that are transferred when (relatively) mature to adjacent keratinocytes. Melanin-accepting keratinocytes are distributed in the basal layer (S. basale) of the epidermis, as well as in the anagen hair follicle bulb. In the latter melanin is specifically donated to keratinocytes that will form the bulky cortex of the hair fiber. Only in epidermis is the process of melanogenesis continuous and UVR-protective. By contrast, in the hair follicle this process is tightly coupled to the hair growth cycle and occurs deep in the scalp beyond direct UVR influence.

While hypopigmentary/ hyperpigmentary disorders are not usually of medical consequence, there remains considerable clinical unmet need. Prominent examples for skin pigmentation include;  vitiligo, melasma, solar lentigines etc., while for the hair include aging-related graying or canities, poliosis etc.

The tonal palette of skin and hair colour that is detectable at the skin or hair surface is the product of a complex interplay of multiple biological events, each with their own regulatory control.  While significant progress has been made in our understanding of the phylogenetically-ancient process that is melanin synthesis at cell/molecular biological and biochemical levels, clinical interventions that can consistently and successfully treat pigmentary disorders, be they pathological or physiological (e.g., aging-related), have largely failed to translate from the laboratory to the clinic or salon. Much of this lack of progress must, in my view, be due to poor translatability of mouse studies to humans or to a failure to fully appreciate the often very significant artefacts of conventional cell/tissue and culture technologies and models.

This presentation will attempt to tease out the gaps in our current understanding of how skin and hair pigmentation is regulated in humans and will focus on how exploitation of this incomplete knowledge is being limited by deficiencies in our laboratory models.

Speaker

  • Dr Des Tobin Full Professor of Dermatological Science & Director - University College Dublin