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Challenges in Cosmetic Formulation

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

Formulating cosmetic products presents many challenges, ranging from regulations, product safety, performance, aesthetics, consumer demographic trends and claim substantiation, in addition to media scrutiny, etc.  To be a successful formulation chemist, one must toggle many priorities with limited resources of time and money, while maintaining market launch timing.  In this blog, a few of the selected challenges will be discussed.

Every Ingredient Should Have a Function.  A formulation chemist should understand the structure-property relationship and the role of each raw material in a formula.  Raw materials are tools for creating formulation options and contributing to tactile sensory, stability and efficaciousness of the formulation.  There are many cosmetic ingredients with multiple functions, providing benefits that meet consumer demands.  By understanding the ingredient function and interactions in the complex composition, chemists can develop better formulation strategies.  At times, a formulator would be asked to “tweak” an existing formulation in order to replace an ingredient in response to a supply chain issue, regulatory constraints or to meet some sensory needs requested by marketing or consumers.  Simply piling ingredients into a formula does not always provide a solution to the problem.  In fact, it can backfire and create instability, or other unwanted issues.  It is important to be familiar with the latest raw material technology by developing long-term partnership with strategic teams (both internal and external contacts).

How to Knockoff a Cosmetic Formula?1 One way to quickly become familiar with a cosmetic formulation is to “knockoff” (or duplicate) an existing formula.  Perry Romanowski published a 10-step strategy to essentially “reverse engineer” a competitor’s formulation.  This is by no means to simply create a “me-too” product, but to thoroughly understand formulation strategy and applications of raw material technology developed by competition.  It should serve as a good practice point for a novice and sometime even a seasoned formulator.  Again, the key points in Perry’s method are to (1) understand raw materials used in a formula by studying its full ingredient list (FIL), (2) read competitor’s patents and publications, and last but not least (3) create, revise and test prototypes, until the desired aesthetics are obtained.

Formulating Existing Formulation Platform.  As mentioned, a cosmetic formulator could be asked to “reformulate” an existing product formulation.  This is typically for continuation of a franchise with small modifications to the marketed formula, or a product launch with new claims, albeit based on existing formulas.  This approach can, for the most part, save time and resources on efficacy and safety testing, in addition to minimizing the potential risks from regulation and/or right-to-market.  Tony O’Lenick describes, in his many publications, “controlled modifications” of existing formulation. It is achieved by: 2 (1) minimally disruptive technology, and (2) functional formulation.  The first approach uses low concentrations of polymeric surfactant(s) to alter aesthetics of existing formulation.  The second strategy pertains to raw material replacement in a formula, i.e., replacing raw materials based on how they function in the formulation.   For certain formulation types, especially mass-market products, it is also imperative to make certain of cost effectiveness for the final formulation.

Developing New Formulation Chassis.  This brings the most challenging and rewarding experience for a formulator, i.e. to create a brand new formulation chassis with a new formulation composition that gives rise to new and enjoyable consumer use experience.  However, the challenges for formulators exist in many areas: (1) developing a stable formula with a plausible right-to-market, and more excitingly, new patent opportunities in the IP landscape, (2) meeting the microbiological, safety and regulatory requirements for the specific product launch markets, (3) achieving efficient scale-up production from laboratory bench experience, and for sustainable business sake, (4) meeting the consumer demographic trends and marketing needs, including claim substantiation and consumer communication, etc.  Due to these multifaceted challenges, this type of formulation is typically managed as a longer-term research project.

Product Performance and Sustainability from a Formula Perspective.  Long before the pandemic of 2020, the personal care industry has seen the rise of “clean beauty” demand from consumers, while the pandemic seems to have accelerated this demand.3  By definition, “clean beauty” product formulation requires the use of safe and non-toxic ingredients with proven efficacy.4  To take it further, we shall take into consideration sustainable development, in order to counteract global warming and environmental changes.4,5  What does it all mean for a cosmetic formulator?  It begins with selection of bio-based, renewable ingredients with respect of biodiversity and societal equality, and minimizing the use of fossil-based, non-renewable raw materials.  During formulation stages, one must also bear in mind the potential water usage to minimize the water footprint, and incorporation of as much as possible energy-efficient process for scale-up during production.6

Conclusion  

Cosmetic formulation has the most exciting challenges in combining science and art in response to the unmet needs from consumers.  A formulation scientist is an artist that creates new textures and influences the sensory perception of the customers.  In this ever-changing world of cosmetic and personal care industry, formulators are the primary driving force of technology and innovation.  No matter what formulation challenges at hand, product performance and sustainability will undoubtedly be the future of cosmetic formulation.

Acknowledgements

The author would like to thank the kind review and comments from Giorgio Dell’Acqua, Hani Fares, Ben Blinder, Howard Epstein, Hy Bui, Ryuji Hara and Ronni Weinkauf.

References:

  1. Perry Romanowski, https://chemistscorner.com/
  2. Tony O’Lenick, http://www.scientificspectator.com/tony-olenick-compilation-of-articles/
  3. NYSCC “At Home Live Series – Clean Beauty”, November 19, 2020.
  4. Giorgio Dell’Acqua, Clean Beauty – Beauty Horizons, December 15, 2020 https://digital.teknoscienze.com/beauty_horizons_1_2020_ww
  5. L’Oréal Sustainability Commitment for 2030. https://mediaroom.loreal.com/wp-content/uploads/2020/06/EN_Booklet_LOreal-for-the-Future_2020.pdf
  6. L’Oréal Product Environmental & Social Impact Labelling Methodologies. https://www.loreal.com/-/media/project/loreal/brand-sites/corp/master/lcorp/documents-media/publications/loreal-pil-methodologie-en01.pdf

Dr. Catherine Chiou holds a BS degree in Chemistry from National Taiwan University and a Ph.D. in Bioinorganic Chemistry from the University of Minnesota.  Catherine’s NIH Postdoctoral fellowship training in Synthetic Chemistry took place at Harvard University.  Her first industrial position was with Unilever Research US in the laundry bleach research program and machine dishwashing detergent research, including I&I applications.

Catherine began her career in cosmetic field at L’Oréal USA in 2001 in the DIMP (International Raw Materials Department).  She worked on all aspects of “innovative raw material” functions, including scouting for new supplier innovations, and managing supplier relationships.  In addition, Catherine took on a role within the PCPC INCI Committee.

Catherine is currently an Associate Principal Scientist at L’Oréal USA in the Cosmetic Application Domain, focusing on developing skin cleansing and makeup removing technologies.  Prior to the current position, she has worked in the skin care research and innovation lab as a senior formulator, contributing towards development of platform technologies and several global launches of skin care treatment products.  She is an inventor for more than 20 US and international patents.

How Many Languages Does our Skin Speak?

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

How Many Languages Does our Skin Speak? A fresh look at what it can it teach us in terms of innovation if we listen.

Inflammation is Just the Beginning:

Inflammation has garnished the attention of mainstream headlines for the past 20 years and has certainly taken center stage describing and managing the current virulence of the pandemic.  With terms like cytokine storm, pre-existing conditions and co-morbidities, what have we learned and what we still need to learn to properly manage the ill effects of inflammation and its impact on health is astounding.  As a biologist, I adopted the general tenant that inflammation is the root of all evil when it comes to aging and disease, particularly in the skin.  Whether its role is in normal aging from a subclinical perspective or pathological in nature in an acute verses chronic situation, inflammation seems to be a rate limiting step or first domino to fall for most underlining causes of both intrinsic and extrinsic aging processes in our largest organ the skin.  Even in the Covid-19 era, we are seeing persistent skin rashes documented post infection, why?  What are we doing right and what should we be doing different?

The good news is that we seem to understand inflammation from a mechanistic point of view.  How reactive oxygen, metals, lipid mediators, enzymes, transcription factors, temperature, microbes and sun play a role in skin inflammation is well documented.  The disconnect here is that we in the industry of cosmetic science have decided to treat the sources of inflammation as individual events rather than a consortium of cumulative ever changing processes designed to mute our first line of defense.  This is akin to putting a lock box around a fire alarm verses reducing existing fire hazards.

In this regard, let us not loose site of the purpose of inflammation, which is to alert and respond to acute threats to homeostasis or skin balance.  Every level of our biological organization has its own cadence on how homeostasis is maintained and managed over time.  From a molecular level, through soluble cytokines (the language of our cells) all the way to behavior responses, evolution has afforded us a great deal of redundancy in this regard, all culminating to the ultimate goal of maintaining health and balance.  In what follows, I hope to serve up a fresh look at how we as skin care technology providers can approach new product designs and formulation innovations that not only address acute disturbances in skin but may ultimately change the way we look and feel about our skin and ourselves as a whole.

The Skin as a Sensory Organ:

The best part of focusing on the skin is that it does so much for us in terms of our survival, health, and our ability to adapt to the environments we find ourselves in on a daily basis.  Furthermore, the epidermis and some of the cell types that reside in it (melanocytes, Langerhans-like phagocytes) are embryologically derived from ectoderm which also gives rise to our nervous system proper.  This is a profoundly underappreciated opportunity as our skin has all of the “gear” needed to effectively communicate with the nervous system as well as the endocrine system and vice versa.   In this regard, we need to integrate the fact that our neural, endocrine, immune, skin microbiome and skin biology are all interlaced and cross talk every moment of our existence.  The ability of our skin to react to its environmental threats through inflammatory processes has opened a window into a world that is vastly more complex and interactive.   It requires a master’s degree in linguistics to hear all the talk between keratinocytes, immune cells, hair follicles and sweat glands and melanocytes.  As a result, this conceptual understanding opens up targets that not only affect the skin proper but our behavior as well.  What if we could understand the autonomic picture our brain has of our skin?  I believe we would see numerous snap shots of skin grafts unique to one another, painted by skin thickness, pH, lipid structure, water content, hair follicle density, immune residence and microbiome attendance.  Could we re-focus our formulation efforts in terms of sensory to be more inclusive of these micro environments and their associated biology?  Could we change the way our brain “sees” our skin?

 

Behavior is driven by how we perceive our surroundings.  Our skin is considered a neurosensory organ much the same way other species use antennae or chemoreceptors to “see” their environment as demonstrated by insects and snakes respectively.  Our skin senses electromagnetic radiation, temperature, chemicals, pH, biological insults, and subtle changes in our microbiome.  It also knows when there are sub clinical changes in chemistry as well as disruptions in barrier and wounding.  All of these stimuli we cannot see with our other senses unless they are out of sync or control.  We tend to focus more on sight and sound as an organism.  Why then do we ignore the largest sense organ we possess when it has so much to say?  More so, all of these stimuli are transmitted to the brain (consciously or unconsciously) and to the surrounding cells and tissues simultaneously, thus having an impact not only on our behavioral responses but on our epidermal biology, our immune and endocrine systems.  Furthermore, the reverse is true.  The brain and adrenals along with the immune cells talk back.  A fundamental requirement for communication is that more than one entity needs to deliver information to another that can receive and react to it.  How cool is it that whatever stimuli the skin observes it is translated via different systems that act in concert to maintain homeostasis and dictate behavior.  As formulators and inventors, the next level of innovation will come from exploiting these lines of communication.  Recall how simple the Wright brother’s solution to flight was compared to the latest version of air travel today.  You will most likely not be in a position to imagine a jet airliner if you never saw the Kitty Hawk.

Immune System Integration:

If things were not complex enough, we need to consider the immune system and all of its abilities and functions as a driver of skin health.  The marvelous thing about our immune system is that it is driven not just by genetics but also by environmental pressures we expose our body to on a regular basis.  The immune system adapts and learns and has a periodicity that is defined by age and time.  Our immune functions start out naive then grow, mature, plateau and decline throughout our lifespan.  Furthermore, our immune system is organized into two systems (innate and adaptive/learned) that together synergize in function.  It even has its own residential lymphoid cells called skin associated lymphatic tissue or SALT which supervises and coordinates your interactions with all things non-self.  From that organization it specializes in various modalities of responses that are classified into 3 groups depending on the type of initiation involved and cytokine profile released into the milieu along with contributions from epithelial cell derived cytokine signals such as IL-33.  For example Type I immunity is relegated to intracellular threats (viruses and parasites) and the production of IFN-g and/or TNFα.  Type 2 immune responses are in ordinance with itch and are caused by harmful substances driven by the secretion of IL-4, IL-5 and IL-13.  Type 3 immunity is specific to extracellular bacterial and fungal infections and characterized by the production of IL-17 and IL-22 cytokines.   It is interesting to note that the cytokine profiles of each type of immunity dictate a specific ordered response by immune tissue, but they also modulate sensory perception and behavior, another key component to our overall host defense arsenal.  For example, IL-33 release from keratinocytes in a compromised epidermal barrier can stimulate local neurons to become hypersensitive and hyper-excitable, thus releasing neuropeptides like substance P and CGRP, which then feedback on the very same keratinocytes to increase their proliferation in an effort to restore the compromised barrier.  As a result, the hypertrophy can further disrupt epidermal differentiation, trap bacteria and acne and/or folliculitis ensues respectively in affected sebaceous gland canals and hair follicles respectively.  Furthermore, antibodies to IL-13 and IL-4 (type 2 immune responses) reduce barrier inflammation which reduces itch in AD stuffer’s.

By grouping immune type cytokine profiles together along with their temporal expression patterns that includes initiation, plateau and resolution makes for a more precise technology development strategy in this regard.

 

A Systems Approach to Understanding:

It is an interesting to note that the nervous system and its functions rely on afferent signals (sensory neurons and their associated stimuli) to understand its place in the environment, whereas the immune system also “senses” our body’s interactions with our surrounding through more of a military surveillance strategy of touch, chemical codes, catabolism and synthesis.  Furthermore, the brain and its neurons are fixed in place converting chemical signals into electrical and back again at supersonic speed whereas the immune system is both static and dynamic adapting and learning at a significantly slower pace alongside the brain.  It evolves and grows.   The interplay between both of these systems tends to out rank the local tissue signals in which they reside. A linear approach to skin therapy has focused primarily on the residential populations of the skin with a peripheral mention of the other systems as secondary is like only listening to one side of the conversation.  Leveraging a systems approach to new skin therapeutics and personal care technologies could lead to significant transformational innovations in product development including new categories of skin care.

 

 

How does all of this work and where are we headed? 

Advances in sensory biology (specifically itch and pain) have elucidated novel mechanisms that arose from our understanding of inflammation.  Itch and pain are great examples of behavior changes as we have all experienced both.  What if by understanding how to modulate these behaviors we could apply these same strategies to resolve dry skin, alter tone and texture, improve radiance and create the de-novo synthesis of endogenous beneficial molecules such as vitamin D, melanin and keratin.  Furthermore, what if we could take these strategies forward to build better nails and hair, modulate sebum quality and quantity and even provide some level of subconscious behavior that could help you lose weight, reduce stress or just be happier?  We spend a lot of time and energy trying to reduce acne which has significant behavior ramifications especially in teenagers, when in actuality, if we could just reduce the erythema in a timely manner, most of the terrible downstream problems would be better tolerated or ameliorated such as post inflammatory hyperpigmentation and self-esteem related syndromes.

Melanocyte Biology Reimagined:

Since melanocytes are the focal point of Post Inflammatory Hyperpigmentation, they could be considered the “conductor” of the cross talk between residential skin cells, neurons and immune processes.  These cells that act as a UV detectors in our skin may in actuality have the ability to sense and focus on other stimuli.  They are of course derived from the same primordial soup as neurons.  If true, these master regulators would need to communicate with and receive signals from all cell types including neurons, macrophages, Langerhans cells and various lymphoid tissues (SALT).  Just like neurons, melanocytes convert energy to communicate.  Here melanocytes convert electromagnetic energy (UV and HEV) into relevant biological signals that initiate signal amplification and recruitment of multiple tissues to ultimately elicit a behavior change.  The same signaling molecules that have a role in the central and peripheral nervous tissue also have a role in cutaneous melanocytes. These include signaling pathways that include Wnt, bone morphogenetic proteins, endothelins, hepatocyte growth factor, fibroblast growth factors, and neurotrophins.

Applying the Concepts:

When afferent sensory neurons fire in our skin, they release neuropeptides in an efferent (reciprocal) manner that has its effects on melanocytes and immune cells simultaneously.  In other words, the skin is already reacting to the stimuli before the brain even gets the signal.  This is an important event as this profile of cellular signals creates a customized code of signals unique to the stimuli, very similar to the basic formula for how your brain remembers a memory.  If by understanding this profiling technic our body uses on the local level we could indeed teach our skin to react in different ways by nudging and modulating profile dynamics.

This concept is already in practice through the use of antibody therapy for psoriasis and atopic dermatitis (AD).  These antibody therapies work by interfering with the cytokine-induced pathways in neurons, important for intercellular conversations with local cytokines which then in turn modulates itch and inflammation.  The immune therapeutic Tofacitinib works through JAK inhibition thus reducing inflammation better than traditional broad spectrum anti-inflammatory strategies (systemic steroids).   Here the traditional modality of treating the source of the problem is over ridden by muting the signal that helps propagate it.  Additionally, this neuron targeted approach is also supported by the observations that patients with inflammatory (AD) experienced resolution of inflammation in body parts that experience nerve loss.  What are we to conclude from this? Chronic inflammation requires communication with the nervous system.

Integration of the Skin Microbiome:

Peeling back yet another layer of the onion, we need to include our newfound tribe the skin microbiome.  In collaboration with the gut microbiome, these two tribes have considerable influence on everyday life as it relates to well-being and health.  If you wonder of their overall purpose, it lies in their ability to adjust tolerance and direct the necessary “activation energy” needed to amplify inflammation, over and above the status quo.  Think of it as immune exercise or conditioning.  The diversity of microbes in and on our body translates and cross-trains all the different biological conversations between the skin epithelia, immune cells and processes along with the existing neural architecture. The “chatter” establishes a level of readiness.  It results in an overall host defense that is primed and semi-activated to address danger and invasion.  When microbiome diversity is lowered or dominated by a few select species, the response is detrimental by two-fold.  One, it allows for re-colonization of the skin by opportunistic invaders which may not be pathological at normal levels but create that cytokine profile or “storm” that trips the balance of cross talk between all the players resulting in an increase in entropy of the whole system.  Chaos, isn’t that what we all work so hard to control?  Two, the low diversity establishes a lower state of readiness and as result the conversations become quieter and limited leaving the health of the skin vulnerable to imbalance and thus, putting negative pressure on behavior.  Can we blame our little friends for our actions and thoughts?  Absolutely!  Just as folks with AD, psoriasis, irritable bowel syndrome and Crohn’s disease.

In closing:

As a result of all this biological chatter we have order and purpose.  It is exciting to see how fundamental understanding evolves.  The integration of multiple languages into a new one with higher purpose, efficiency and meaning is an evolutionary learning process.  To naively think we understand the language of our biological complexity is limiting our potential.  We must integrate and transcend across the mechanistic understanding and incorporate a multi-disciplinary approach to new concepts and ideas.  We need to explore new ways to achieve desired responses and ultimately behavior that favors well-being for all ages and health both physically and mentally.  I can’t help but wonder how many times we find ourselves enjoying a good meal, listening to our favorite music or being with friends and family that creates a sense of well-being that is most grounded.  Isn’t that what you would like to have in a product?  These feelings can’t be solely due to cerebral contentment, you have billions of other contributing opinions looking out for the same sense of well-being.  It’s time to listen more intently to those conversations.  One could have a hard time arguing which system truly dominates the conversation and thus our behavior and as a result our health.  Let not your strategy and ideation be limited to just one language.

Inspiration was gleaned from the following references:

The Neuro-Immune Axis in skin Sensation, Inflammation and Immunity, Anna M. Trier et. al., J Immunol, 2019 May 15: 202(10): 2829-2835.

Melanocytes: A Window into the Nervous System, Mina Yaar, et. al. Journal of Investigative Dermatology Volume 132, Issue 3, Part 2, March 2012, Pages 835-845

Inflammatory Resolution: New Opportunities for Drug Discovery, Derek W. Gilroy, et. al., Nature Reviews /Drug Discovery May 2004, 401-416.


Michael Anthonavage
VP of Operations & Technology

Eurofins CRL Cosmetic Testing, Inc.

Michael Anthonavage has 20+ years of experience in personal care product development and a career spanning background in skin biology. Michael has extensive knowledge in product development and product design.  He specializes in R&D to marketing translation, including claims validation both in-vitro and in-vivo. He is an engaging public speaker and product technology advocate with an ability to marry complex ideas and concepts to various consumer needs. Michael is currently the VP of Operations & Technology at Eurofins CRL Cosmetic Testing, INC.  Michael’s previous positions have involved R&D leadership positions at Johnson & Johnson Consumer Products, Presperse and Vantage Specialty Chemicals.  Michael is currently on the NYSCC Scientific Advisory Board and has won a variety of industry awards for his contributions in research and product development.   He has a number publications and patents to his name and continues to be an influential speaker in the personal care, bioinstrumentation and skin testing arena.

 

 

An Overview on Hair Porosity

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

Introduction

Human hair is characterized by several descriptors, some of which influence how the hair behaves and responds to cosmetic products.  Common descriptors include texture, density and diameter.  Porosity is another relevant descriptor of hair that merits further attention.  It is advantageous for the industry to consider aspects of hair porosity given the rise of customization in hair care.  Further, the industry has become increasingly more interested in textured hair care.  Individuals with textured hair, hair that is naturally wavy, curly or coily, are more likely to have more porous hair than individuals with straight hair (1). Hair porosity resonates with textured hair consumers, especially considering that moisture and breakage are top concerns among this demographic (2).  The objective of this blog is to present a primer on hair porosity and its relevance to the cosmetic chemist and consumer alike.

Overview of Hair Porosity

Hair porosity describes the extent to which hair absorbs and retains water, products and treatments based on the integrity of the cuticle.  Porosity can be influenced by both genetics and hair grooming practices to varying degrees.  This blog will focus on the extremes of low and high porosity, but it should be noted that a mixture of low, normal and high porosity hair fibers can certainly exist in a head of hair.  Additionally, porosity can vary along the length of the hair fibers.

Normal or medium porosity hair absorbs and retains water reasonably well; hair can absorb 75% of the maximum amount possible within 4 minutes (3).  Normal hair is also receptive to chemical treatments such as bleaches, colorants and relaxers, and the results are generally predictable.

In low porosity hair, the cuticle layers are reinforced and lay flat leading to hair that is more resistant to water and chemical treatments.  From a consumer perspective, this is realized if  1.) the hair takes a significant amount of time to wet and dry, 2.) products build up easily on the surface rather than absorbing, 3.) protein treatments yield a stiff feel, and/or 4.) chemical treatments are less effective than expected.

In high porosity hair, the cuticle is compromised by configurational, mechanical and/or chemical stresses.  Textured hair represents a good example of how configuration can influence porosity.  Curls and coils are characterized by twists that lead to cuticle lifting at various points along the fiber, and this is more prevalent in the more elliptical hair fibers characteristic of individuals of African ancestry.  Mechanical stresses from daily grooming practices such as combing, brushing and hygral fatigue from repeated wetting (swelling) and drying (deswelling) can damage the cuticle over time, thereby exposing hydrophilic areas.  Chemical treatments such as oxidative colorants and ultraviolet radiation can affect hair porosity by oxidizing the protective surface lipids (3,4).

From a consumer perspective, high porosity presents as hair that absorbs water and dries quickly, maintains a dry feeling, experiences excessive frizz and breaks easily in some cases.  While high porosity hair quickly absorbs water, it also loses water quickly. The effects of chemical treatments are also accelerated and inconsistent in some cases, which can lead to damage.  For example, porous hair accepts hair colorants faster and the treatment can result in a cooler tone than that observed on less porous hair (5).

Consumer & Technical Methods for Hair Porosity

Select consumer and technical methods used to evaluate hair porosity are highlighted below.  Simple qualitative methods such as the Float Test and Spray Test have limitations but can potentially give a general idea under controlled conditions.

 – Float test: A qualitive assessment of porosity is made based on how quickly a clean hair fiber sinks when placed in room temperature water.  If the fiber more quickly sinks to the bottom, then it is porous.  If it floats over time, then it is likely low porosity.

– Spray test:  A qualitative assessment of porosity is made based on the behavior of water when sprayed on clean dry hair.  High porosity hair should adsorb the water more quickly than lower porosity hair, which would instead have visible beads of water and a longer dry time.

 – Dynamic Vapor Sorption (DVS) (6): The weight of hair is recorded as a function of increasing or decreasing humidity.

 – Gas Adsorption & Pore Size Analysis (7): Hair samples are subjected to nitrogen adsorption followed by mapping of the distribution and sizing of pores.

 – Fiber Swelling: The dimensions of a hair fiber are measured as a function of exposure to water. 

Hair Care Considerations by Porosity

The key concern for low porosity hair is hydrating the hair.  This can be facilitated with the use of a steamer, which simultaneously opens the cuticle with heat and infuses water vapor into the hair (8).  The steamer can be used to aid penetration during deep conditioning or to revitalize and moisturize hair as needed during styling.  The Q-Redew Handheld Steamer has become a quite popular tool.  Additionally, neat or formulated light-weight polar saturated oils can slowly absorb into the hair (1).  Rele et al demonstrated that coconut oil supports hair moisture retention and fortification by reducing water sorption and hygral fatigue (9).  Products that are less likely to penetrate the hair and result in buildup, i.e. some proteins, butters, etc. should be avoided in significant amounts, while those that contain humectants such as glycerin can be useful.

As the key concern for high porosity hair is moisture retention, consumers with this hair type benefit from sealing the hydrated hair with oils.  Consumers with textured hair frequently employ product layering to help retain moisture (in addition to styling).  This is referred to as the LOC or LCO method, in which the hair is hydrated with liquid or leave-in conditioner (L), followed by an oil (O) to seal the hair and then a creamy moisturizer/styler (C).  Polyunsaturated oils like avocado oil reportedly work best for high porosity hair.  While scientists have demonstrated that perceived hair moisturization does not correlate with actual hair moisture content (8,10), this method warrants attention given the satisfaction expressed by consumers.  It is plausible that the perceived improvement in “hair moisture” resulting from product layering techniques is due to the combined influence of at the least some of the following variables on the modification of the hair’s tactile properties: presence of product on the surface, oil penetration, and actual moisture content or localization.

In addition to sealing the hair with oils or product layering, high porosity hair can benefit from protein treatments.  Proteins can fill the voids of a compromised or lifted cuticle via film formation and penetration into the fiber. Further, products with significant levels of humectants should be avoided depending on the climate.

While there are marketed products that target hair porosity concerns, efficacy data are not available to the greater scientific community.  This opens the door of opportunity for the technical community to link technical capabilities such as the aforementioned methods with compelling data-backed product/ingredient stories.

Conclusion

As personalization in cosmetics/personal care continues to grow, the industry could benefit from further considering hair porosity.  Opportunity exists to further explore the distribution of hair porosity types and the link between porosity and CMC lipids, protein content, etc. beyond the current understanding.  Further research into this parameter could lead to ingredients, formulations, test methods, styling implements, and communications better tailored to address various hair porosities more effectively.  Linking consumer perception and practices with appropriate technical principles will be useful in meeting the needs of diverse hair types.

References

  1. Davis-Sivasothy, The Science of Black Hair (Saja Publishing Company, Texas, 2011), pp. 47-50, 78-91.
  2. Texture Media LLC. Texture Trends Consumer Study 2018.
  3. Dawber. Hair: its structure and response to cosmetic preparation, Clinics in Dermatology, 14, 105-113 (1996).
  4. Syed. Correlating porosity to tensile strength, Cosmetics & Toiletries, 117,11, 57-62 (2002).
  5. M. Frangie, L. Barnes, and Milady. Milady’s Standard Cosmetology Textbook, 1st ed. (Cengage Learning, Massachusetts, 2012), pp.630-631.
  6. Evans, “Adsorption Properties of Hair,” in Practical Modern Hair Science, T. Evans and R. Wickett. Eds. (Allured Business Media, Illinois, 2012), pp. 333-365.
  7. Z. Hessefort, B.T. Holland, and R.W. Cloud. True porosity measurement: a new way to study hair damage mechanisms, J. Cosmet. Sci., 59, 263–289 (2008).
  8. Schmid, H. Hair care appliance and method of using same. U.S. Patent 8,136, 263, filed August 21, 2008, and issued March 20, 2012.
  9. S. Reles and R.B. Mohle, Effect ofmineral oil, sunflower oil, and coconut oil on prevention of hair damage, J. Cosmet. Sci., 54, 175-192 (2003).
  10. Davis. Moisture vs. Moisturization: Understanding the Consumer Benefit, P&G Beauty Care Presentation, TRI 5th International Conference on Applied Hair Science (2014).

 


 

Dr. Amber Evans is a cosmetic industry professional with over a decade of experience and expertise in the science of hair and skin care.  In her current role as Senior Manager of Product Development at Moroccanoil, she is responsible for driving the development of high-quality innovative hair & body care products for the successful global brand.  She previously worked at as a development scientist at BASF Corporation, where her contributions spanned multiple market segments, including hair, body and oral care, and the technical areas of innovation and claims testing over eight years.

Dr. Evans earned a Ph.D. in Pharmaceutical Sciences (Cosmetic Science focus) from University of Cincinnati and a B.S. in Chemistry from North Carolina Agricultural & Technical State University.  She has conducted extensive research into the influence of water hardness on hair and has contributed to initiatives including upstream research for hair colorants, hair conditioner formulation and clinical testing for skin/shave care applications at The Procter & Gamble Company.  She has also authored hair care research publications, contributed content to NaturallyCurly.com, the leading resource for textured hair care, and featured on multiple platforms that support aspiring scientists and early career professionals.  As a mentor, active member of the Society of Cosmetic Chemists (SCC) and of the NYSCC Scientific Committee, peer reviewer for the Journal of Cosmetic Science and member of the Advisory Board for the University of Cincinnati Cosmetic Science Program, Dr. Evans is dedicated to influencing the progression of the cosmetic field.

 

Multifaceted Dimensions of Special Effect Pigments

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

Introduction

Light dances on the surface of special effect pigments before it bounces off angles to bend and blur lines with optical diffusion, creating depth, offering dimensionality, sheer luminous glow or a dazzling, eye catching sparkle. Used in everyday products across a wide array of industries such as color cosmetics, personal care, auto, paint and fashion, an effect pigment can display color, offer multiple effects, impart color travel as it reflects and refracts light through many angles. The chemistry and manufacturing process impact the unique visual performance of these special effect pigments but may not be as appreciated or understood compared to the end product’s desirable effects. Taking a closer look at the use of effect pigments in the beauty industry as their function and use allows for eyeshadows to take on properties offering intense color depth and a captivating sparkle, stunning gemstone effects in nail polishes and for highlighters to impart a soft focus contour on cheek bones.

The special effect pigment market has been forecasted to increase over the next 5 years due to high consumer demands seeking to continue personal care upkeep particularly within the nail and eye category as a result of Covid-19.   An evolution is not only seen regarding effect pigments usage through the years in cosmetic products to attain desired results, but also with an important transition to address sustainable platforms looking to safeguard global resources. These initiatives intertwine the beauty industry with heightened levels of innovation to support ethical and environmental objectives.

Intricate Composition

Special effect pigments, often referenced as pearlescent pigments, have manufacturing processes that are as dynamic as the product effect itself.  Visual properties are created with a starting base layer known as a substrate. Initial determination between a natural or synthetic substrate help to establish expected properties and unique characteristics when used in a product. Natural options include Mica, Kaolin, and Rayon. These ingredients are Generally Recognized as Safe (GRAS) and create similar effects to synthetic options such as fluorophlogopite, boron nitride, and glass flakes/borosilicates. Differentiation is demonstrated through optical impressions with the level of reflection, opacity, and interference offered.

Depending on the selected substrate and desired end use, the manufacturing process plays a critical role to yield the product consumers are accustomed to seeing in finished goods. Review of the process cycle used when mica is the substrate offers an opportunity to demonstrate the level of detail involved during development. The mined mica is coated typically with Titanium Dioxide or oxide metals during processing. This occurs when a base and acid are combined in a reactor used to calcine the substrate at variable high temperatures. Impurities are then filtered off, and the process is completed through blending. The thickness of the coating on the substrate directly determines elements of color and can offer interference effects when alternating layers of oxide metals are used or combined with transparent spacers to create optical variable pigments for color travel. Observed color effects are directly correlated to the thickness of the coating as it increases and decreases. The thickness of the coating impacts color development ranging from gold, red, violet, blue to green translating from 70 nm to 360 nm in measurement, respectively. Particle size of the effect pigment plays a critical role as well in the brilliance. Smaller sizes closer to 10 µm impart more of a soft texture matching a satin sheen coverage; larger sizes closer to 60 µm displays more of a dazzling pearlescent appearance; while an average micron size of 125 and above sparkle.

Enhancements

Effect pigments similar to iron oxides and dyes are not necessarily easy to add to formulas as it is dependent on the chassis composition. Stability, color shift, and undesirable payoff performance can be experienced by a formulator during product development as a result of polar hydroxyl groups with adsorbed moisture on the effect pigment.  Surface treatments on effect pigments whether physical or chemically added can address many common drawbacks to ease dispersion into formulas, improve outcome of stability and other unique benefits based on the chemical properties of the specific treatment used.

Sustainable Vision

Ethical and environmental concerns prompted many forward-thinking beauty organizations to create innovative solutions and restriction lists in response to negative aspects of the effect pigment supply chain. Focus on child labor, traceability, and environmental considerations are needed for a better tomorrow to keep our world beautiful more than just on the surface. As a result of these issues being uncovered, opportunities arose for alternative material solutions paired with philanthropic initiatives to give back to communities. As a result, demand to innovate in support of environmentally considerate substrates such as bio-based options were developed. Bio-based effect pigments look at upcycling to introduce cleaner alternatives with similar appearances and attributes especially compared to PET glitters. The ban on microplastics in recent years has exposed PET glitter due to their small size and inability to breakdown as they enter the environment and can end up on our dinner tables. Due diligence has spurred innovation on many levels as formulators seek new understandings to develop similar product effects and encourage consumer education in hopes to inspire mindfulness.

Formulating Tips

  • Effect pigments should be incorporated carefully into batches and sweep mixing blade is recommended. It’s best to avoid particle size optimization with homogenizers as they are fragile materials, and it jeopardizes the effect of larger micron sizes when sheer force is applied. When the effect pigment surface is deformed the sparkle effect is reduced or no longer visible.
    Take time to understand the material’s specifications from the certificate of analysis (COA). For example, when formulating anhydrous formulas the oil absorbency and ingredient ratios determine ease of pourability, skin feel, and payoff. A balanced, high performing formula takes into consideration these aspects to make improvements and/or alternatively to select a surface treated option if a high effect pigment loading is required.
  • Caution is recommended with composites that contain Ferric Ferrocyanide, Carmine or when used in a formula that will contain Avobenzone with Titanium Dioxide coated pigments as this will likely shift color and cause other adverse stability outcomes.
  • Understand global regulations to ensure that each of the effect pigment constituents meet regulatory requirements and areas of use for distribution. Not all pigments are allowed in the eye area and micron size is another critical aspect to consider pending product positioning. Generally, special effect pigments for eye product have a micron cap at 150. While this can pose as a challenge to match prototypes there are other available options such as synthetic fluorophlogopite that do not follow the same particle size restrictions.
  • Color matching should be done with colorants, iron oxides and dyes, then to use effect pigments to compliment. Higher usage levels of pigments should be used to achieve deeper, more intense tones and will offer a good base color to make it easier to shade match instead of being reliant on pearls alone where there is less color consistency. This technique promotes cost efficiency for a more economical approach to shade matching as well.

Conclusion

Special effect pigments have wide applicability to impart visually appealing impressions. The characteristic properties are heavily reliant on the chemical framework and manufacturing process implemented to determine desirable elements. The beauty industry counts on effect pigments for their role to enhance the color appeal, effects, and texture in finished goods. Even as much as the consumer looks for these alluring effects, sustainable platforms are necessary as awareness increases. Sustainability has invigorated innovation within this market that will hopefully continue to support technological advances with novel solutions.

References

  1. Cramer WR. Hidden Secret of Effect Pigments. PCI Magazine, October 3, 2017 – https://www.pcimag.com/articles/102924-hidden-secrets-of-effect-pigments
  2. Maile FG, Pfaff G, Reynders P. Effect pigments-past, present and future. Progress in Organic Coatings, 54 (3): 150-163, 2005
  3. Special Effect Pigments Market Size 2020 Industry Demand, Share, Trend, Industry News, Growth, Top Key Players, Business Statistics and Forecast to 2026. Market Watch, October 8, 2020.

Acknowledgements

Frank Mazella, David Schlossman, and Yun Shao for inspirational talking.


Stacey House

Stacey is the Vice President of Research and Innovation at KDC/One’s East Coast R&D leading the talented teams at Acupac, Chemaid, Innovation Lab and Kolmar. Her strong team is focused on developing elevated, high touch formulas in categories spanning the personal care industry. Previously, she was the Director of R&D at Mana Products, Director of Applications at Kobo Products, and had also worked in Coty and Revlon’s R&D labs. She holds a patent on Low Viscosity Phenyl Trimethicone Applications and has written several published industry articles. Stacey graduated from Northeastern University with MBAs in Operations, Supply Chain, and International Business and received her Bachelors of Science degree at Rutgers University-New Brunswick.

 

Delivery Systems for Antioxidants

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

Introduction

As the body’s first defense against the elements, skin is frequently exposed to electromagnetic radiation from the Sun, which can lead to a variety of detrimental conditions such as photoaging, photoimmunosuppression, and photocarcinogenesis. Reactive oxygen species are largely responsible for the initiation of these disease states in skin and are mostly due to exposure to ultraviolet light, but have also been shown to result to some extent from the absorption of visible and infrared light. Considerable efforts have also been made to better understand the effects of pollution on the skin from a free radical and reactive oxygen species point of view.

Antioxidants

The use of antioxidants in various skin treatments is a sound approach to improve the overall health state of skin [1]. This statement is supported by a wealth of research conducted over the last several decades toward better understanding how antioxidants mitigate the effects of solar radiation. Topical application of antioxidant-containing products reduces the deleterious effects of solar radiation exposure of the skin.

While some antioxidants may offer some photoprotection as a solar filter, the majority of their mechanisms are through their antioxidant capacity or immunomodulating effects. Some of the most common antioxidants in skin care formulations are vitamin E, vitamin C, and coenzyme Q. Historically, these were probably the most studied antioxidants due to their importance in the endogenous antioxidant system.

Equally important are a vast majority of botanical extracts, which are chock-full of phyto-antioxidants. In recent years, research has focused on understanding the antioxidant behavior of polyphenols in an attempt to harness their protective properties for skin. In some cases, specific polyphenols are used in formulation while in others the extract is directly added.

 

Topical Application of Antioxidants

Topical application of antioxidants is the most straightforward approach to fortify the skin. As compared to dietary intake of antioxidants, in many cases topical application allows: (1) greater concentrations to reach tissues, (2) greater tissue specificity, and (3) reduced side effects to other organs. Unfortunately, not all antioxidants (e.g., from extracts) easily cross the stratum corneum barrier. The fact that some antioxidants are not able to penetrate the skin could be considered a positive toxicological benefit. Skin permeation and antioxidant stability can be enhanced by utilizing state-of-the-art delivery systems.

One of the major factors with antioxidant stability in skin care formulations stems from the need to prevent oxidation within the formulation and also to deliver to the skin an active antioxidant that is bioavailable. In many cases, formulations are based on carrier systems in which oxidation can occur in the oil phase, water phase, or at the interface. More often than not, oxidation occurs at the interface. Some of the hurdles facing formulators in the antioxidant arena are a result of stability issues with antioxidants that are intended to be delivered to skin.

 

Antioxidant Carrier Systems

The use of carrier systems represents a real asset for the delivery of antioxidant to skin and can include various types of emulsion, vesicular, or lipid particle systems.

Emulsions systems

These systems are dispersions of oil and water and can refer to microemulsions, nanoemulsions, and Pickering emulsions. Microemulsions and nanoemulsions are characterized by the dispersion size of the emulsified phase, while Pickering emulsions refer to a type of emulsion that is stabilized by solid particles.

Vesicular systems

These systems consist of liposomes, phytosomes, transferomes, ethosomes, and niosomes. Liposomes are the most popular vesicular system used in personal care applications and are composed of concentric layers of phospholipid bilayers spherically shaped with a hollow center for the active ingredient. Phytosomes are vesicles of phospholipids that have high affinity for phytocompounds, such as polyphenols. Transferosomes are lipid vesicles that consist of fatty acids and a small amount of ethanol. They are more elastic than liposomes, which improves their deposition characteristics. Ethosomes are lipid vesicles that contain even greater amounts of ethanol, yielding a more flexible vesicle. Niosomes are lamellar vesicles based on nonionic surfactants. Due to the nature of the surfactants in niosomes, crossing the stratum corneum is more facile than in the case with other vesicles.

Lipid particle systems

These systems consist of lipid microparticles and lipid nanoparticles. Lipid microparticles are created by a process known as microencapsulation where a small solid or liquid droplet is surrounded with a thin layer of shell. Lipid nanoparticles are further categorized as solid lipid nanoparticles and nanostructured carriers. Solid lipid particles consist of a lipid system in the solid state at room temperature with a thin surface coating on the outside as a stabilizer. Nanostructured lipid carriers, on the other hand, are more complex and contain lipids both in the solid and fluid phase. Typically, such systems can increase the stability of antioxidants and their permeation efficacy to skin as well as reduce irritation. The reader is referred to a review by Pol and Patravale for a nice introduction to the subject [2].

 

Nanoparticle and Nanocarriers

Nanoparticles and nanocarriers continue to be at the forefront of skin care research for their potential at stabilizing and delivering antioxidants to the skin. For example, gold nanoparticles are known for their anti-inflammatory, antiaging, and wound healing properties in skin care. A recently published study demonstrated how polyphenols from an aqueous extract can be used to reduce metal salts—in this case gold—into nanoparticles [3]. In another study, gold nanoparticles wrapped with chitosan were used to stabilize ellagic acid [4]. In both cases, green technology was used to fabricate the nanoparticle structures.

Nanoencapsulation is another area that shows much promise for the delivery of antioxidants to skin. Lipid-core nanocapsules containing resveratrol and lipoic acid have enhanced chemical stability and photostability as compared to the non-encapsulated forms of the molecules [5]. TiO2 is a nanoparticle found in many sun protection products. It functions by scattering incoming UV rays from the Sun and preventing photodamage to the skin. Researchers at Sabanci University in Istanbul found enhanced cellular penetration and antioxidant properties of quercetin-TiO2 nanoparticles, as compared to quercetin alone, in studies carried out on fibroblast cell cultures [6].

 

Concluding Remarks

Some of the challenges with the conventional delivery of antioxidants stems from their poor solubility, limited shelf-life stability, compromised photostability, and low degree of skin permeability. Delivery systems enhance the ability of antioxidants to carry out their function. Conventional systems used to deliver antioxidants consist of emulsion, vesicular, or lipid particle systems. In recent years, a great deal of interest has evolved in using nanoparticles as stabilization enhancers and delivery agents for antioxidants. Nanoencapsulation also offers much promise and has been shown to enhance the chemical stability and photostability of antioxidants.

 

References

  1. McMullen, R., Antioxidants and the Skin. 2nd ed. 2019, Boca Raton: CRC Press.
  2. Pol, A. and V. Patravale, Novel lipid based systems for improved topical delivery of antioxidants. Household and Personce Care TODAY, 2009(4): p. 5-8.
  3. Haddada, M., et al., Assessment of antioxidant and dermoprotective activities of gold nanoparticles as safe cosmetic ingredient. Colloids Surf B Biointerfaces, 2020. 189: p. 110855.
  4. Gubitosa, J., et al., Multifunctional green synthesized gold nanoparticles/chitosan/ellagic acid self-assembly: Antioxidant, sun filter and tyrosinase-inhibitor properties. Mat Sci Eng C, 2020. 106: p. 110170.
  5. Davies, S., et al., Simultaneous nanoencapsulation of lipoic acid and resveratrol with improved antioxidant properties for the skin. Colloids Surf B Biointerfaces, 2020. 192: p. 111023.
  6. Birinci, Y., et al., Quercetin in the form of a nano-antioxidant (QTiO2) provides stabilization of quercetin and maximizes its antioxidant capacity in the mouse fibroblast model. Enzyme Microb Tech, 2020. 138: p. 109559.

 


Roger L. McMullen, Ph.D. – BIO

Dr. Roger McMullen has over 20 years of experience in the personal care industry with specialties in optics, imaging, and spectroscopy of hair and skin. Currently, he is Principal Scientist in the Material Science department at Ashland Specialty Ingredients G.P. Roger received a B.S. in Chemistry from Saint Vincent College and completed his Ph.D. in Biophysical Chemistry at Seton Hall University.

Roger actively engages and participates in educational activities in the personal care industry. He frequently teaches continuing education courses for the SCC and TRI-Princeton. In addition, Roger is an Adjunct Professor at Fairleigh Dickinson University and teaches Biochemistry to students pursuing M.S. degrees in Cosmetic Science and Pharmaceutical Chemistry. Prior to pursuing a career in science, Roger served in the U.S. Navy for four years on board the USS YORKTOWN (CG 48). He is fluent in Spanish and Catalan.

 

Formulating effective and stable W/O emulsions

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

Cosmetic chemists are an innovative, curious, and creative group of scientists, continually looking to formulate the most effective and pleasing products for the world’s consumers. Yet when asked to create the galenic forms most often requested by marketing – creams and lotions – the “default emulsion” is almost always oil-in-water (O/W). While O/W systems offer good sensory properties and ease of manufacturing, the primary alternative system – water-in-oil (W/O) – offers distinct advantages, among them long-lasting adherence to the skin and improved water resistance. So why isn’t W/O used more often? Because (a) it is difficult to create a stable W/O system, and (b) the esthetics of a W/O emulsion are often undesirable (sticky, tacky, thick…).

Let’s cover some key concepts to enhance stability when formulating W/O emulsions:

  1. When making W/O emulsions, high energy is required

Why do we need high energy when making a W/O emulsion? High energy brings several benefits to your W/O system, altogether contributing to a stable emulsion:

  1. Creates high energy dissipation rates 1,2
  2. Controls particle size of the dispersed phase of the emulsion 1,2
  3. Reduces interfacial tension 1,2

To achieve the desired results, one may use high-energy equipment such as a rotor stator/homogenizer or a deflocculator at moderate to high shear.

Let’s take a closer look at each…

A) Dissipation rate refers to the rate of conversion of turbulence into heat by molecular velocity.

Here is a simplified energy flow chart when you are creating a W/O emulsion:

Turbulence, initiated by the high-shearing rotor stator, transfers its energy into kinetic energy within the W/O system. That energy of motion is converted into the large velocity gradients of the dispersed droplets of various sizes. And finally, the energy of the rapidly moving particles is converted into heat through dissipation.2

This is a very simplified flowchart, as there are many other variables involved, but the take-home message here is that the higher the conversion of energy into heat, the higher the dissipation energy, the more kinetically stable emulsion. Essentially, we do not want any energy left in the emulsion, especially in those water droplets because that can lead to instability.

B) The energy applied when creating a W/O emulsion affects the particle size of the internal phase of an emulsion.

As mentioned before, high energy processes will use rotor stators/homogenizers, while a low energy process may use simpler blades (turbine stirrer, propeller, or blade stirrer). If you use high energy, you will achieve a finer, more evenly dispersed emulsion, which is exactly what you want, as this is more stable.

But if homogenization is too mild, due to your equipment and/or shearing speed, your W/O emulsion will be highly poly-dispersed, meaning, there will be a wide size distribution in the dispersed droplets, which can lead to instability. 

C) And finally, we need to use high energy with W/O systems because it reduces the interfacial tension (energy present at the water-oil interface).

This benefit is a result of the other two: The more heat that is given off, the less energy and mobility in the dispersed water phase. And the smaller the average droplet size of the dispersed phase, the more the stability increases. Altogether, there is less energy remaining at the water-oil interface, so water droplets are less likely to coalesce and will remain stable within the continuous oil phase. 

  1. Electrolytes must be used

Electrolytes – inorganic salts such as magnesium sulfate or sodium chloride – must be present in the emulsion because they will stabilize your system through various mechanisms of action. For example, NaCl has been shown to decrease the particle size through electrostatic and steric repulsion in the droplets.3 CaCl2 has proven to decrease attractive forces between water droplets.3 And MgCl2 can reduce interfacial tension and enhance interfacial film strength.3

Each of these mechanisms may prevent one or more of the following from happening.

1) Ostwald ripening, also referred to as disproportionation, is caused by the difference in solubility in emulsion droplets. Smaller droplets are more soluble than larger ones, and with prolonged time, the smaller droplets tend to diffuse in the bulk and are deposited on larger droplets. Therefore, larger droplets eventually grow at the expense of smaller ones. Adding salts will counterbalance the driving force for Ostwald ripening, which is related to the total pressure and pressure in the droplets.3

2) Sedimentation is another unstable condition where there is no change to the droplet size, but droplets move to the bottom. The addition of various salts could improve stability by decreasing particle size and reducing the interfacial tension. Salts can allow for tighter packing of surfactant molecules at the O/W interface.3

3) Coalescence is when droplets join, creating larger sized droplets with water separation at the bottom. Adding salts will reduce the attractive forces between water droplets, which will reduce their collision frequency, and thereby prevent droplet coalescence and increase emulsion stability.3

  1. Depending on the emulsifier, the polarity of the oils used must be specific

Unlike O/W systems, the polarity of the oils used in the oil phase has an outsized influence on the stability of the emulsion, and the performance of high-polarity vs. low-polarity oils will be significant. This is because of the “like dissolves like” rule. In general, chemicals of similar polarities demonstrate better interaction. If the lipophilic tails of your emulsifier are polar, perhaps having esters or hydroxyl groups in its carbon backbone, for example, then the emulsifier is better suited in an oil phase of medium to high polarity. The opposite holds true as well. If the polarity of the oil phase does not match that of the emulsifier, the emulsion will not be stable.

Now, let’s talk briefly about the esthetics of W/O emulsions

W/O emulsions are often tacky or draggy, leaving an unpleasant skin feel and an uncomfortably thick layer of product. Also, as W/O systems are often used with pigments, many common emulsifiers do not have the correct compatibility with the wide variety of pigments used today, resulting in non-homogenous dispersions of the pigments within the emulsion. Many traditional W/O emulsifiers were not designed to address issues of skin feel or pigment dispersion, but modern advances in esterification chemistry allow for the creation of a new generation of emulsifiers that provide perceptibly improved sensory characteristics.

It can be suggested that the use of an emulsifier based on polyglycerol chemistry is especially suited to W/O systems due to enhanced stability resulting from large polar headgroups. (Incidentally, polyglycerol chemistry is considered “green” and advantageous when formulating natural or clean products…) Esterifying a polyglycerol backbone with other esters will significantly effect both skin feel and pigment dispersion properties; for example, the use of a ricinoleic acid ester could provide fluidity and improved skin feel, while the use of a hydroxystearic acid ester could improve the dispersibility of both coated and uncoated pigments.

With these concepts in mind, formulating a W/O emulsion can result in an elegant product satisfying the end consumer while meeting the requirements of marketing, allowing the creativity of the chemist to move “beyond the box” of traditional cosmetic emulsions.

References

  1. Turbulence and multiphase flow. http://www.lowshearschool.com/?page_id=16919
  2. The effect of shear on oil-water mixture. http://www.lowshearschool.com/?page_id=16933
  3. Zhu Q , Pan Y, Jia X, Li J, Zhang M, Yin L. Review on the stability mechanism and application of water-in-oil emulsions encapsulating various additives. Comprehensive Reviews in Food Science and Food Safety, 18 (6): 1660-1675, 2019

Leor Fay Tal is the Technical Marketing Leader for the Personal Care division of Gattefossé USA. She delivers information on trends and consumers, provides technical marketing support to the company’s sales teams and agents across North America, Canada, and Mexico, and works to promote knowledge and understanding of the company’s ingredients. Prior to Gattefossé, Leor Fay had worked in the R&D Powder Laboratory and then as the Raw Material Regulatory Affairs Specialist at MANA Products. Leor Fay is also an active member of the NYSCC. She organized the April 2018 event Cosmetics in the Middle East, A Regulatory Perspective and now serves as the Secretary for the executive board.

 

 

 

 

Ben Blinder is the Senior Director for Gattefossé USA – Personal Care Division, where he is responsible for the strategic direction and performance of the cosmetic business for Gattefossé in the US and Mexico. Ben holds a chemical engineering degree from Lehigh University and has been working in the personal care industry for 32 years, with extensive experience in strategic and long-range planning, sales and technical management, and new technology search/discovery.  Ben also serves on the NYSCC Scientific Committee.

 

 

 

 

Sunscreen Monograph Proposed New Rules and its Impact on Formulations-Part II

by NYSCC NYSCC No Comments

In my recent blog published in August, changes to the current sunscreen tentative monograph were proposed.  These changes are probably the most drastic changes to the sunscreen monograph since its inception.  In this section, I would like to tackle two key areas related to the changes requested by the FDA.  The first one is the human pharmacokinetics Maximal Usage Trial (MUsT) for sunscreens conducted by the FDA and published in the Journal of the American Medical Association in May 2019.  The second is the response from the Personal Care Product Council (PCPC) to the requests from the FDA for additional safety data.

The FDA conducted a MUsT trial on 4 sunscreen formulations.  The products consisted of 2 sprays, one lotion and one cream. A detailed description of the products used in the study and the sunscreens concentrations used is displayed in Table I below.

Table I

Concentrations of sunscreens in all treatments

Treatment Percent sunscreen contents per label
Avobenzone Oxybenzone Octocrylene Ecamsule
Spray 1 3.00 6.00 2.35 0.00
Spray 2 3.00 5.00 10.00 0.00
Lotion 3.00 4.00 6.00 0.00
Cream 2.00 0.00 10.00 2.00

Twenty-four subjects were enrolled in the study and were randomized into 4 groups.  Each treatment was studied on 6 individuals. All subjects finished the study except one.  Products were applied at a rate of 2 mg/cm2 on 75% of the body area.  Products were applied by a trained expert and were re-applied every 2 hours four times a day.  The study ran for 4 days and panelists were kept indoors.  Thirty blood samples were collected from each panelist over a period of 7 days and were analyzed for their concentration of sunscreens using a validated HPLC method.

Mean maximum plasma concentrations for all sunscreens were calculated for the four treatments and are displayed in Table II.

Table II

Geometric mean maximum plasma concentration for all treatments

Treatment Geometric Mean Maximum plasma concentration, ng/mL (%CV)
Avobenzone Oxybenzone Octocrylene Ecamsule
Spray 1 4.0 (60.9) 209.6 (66.8) 2.9 (102) Not applicable
Spray 2 3.4 (77.3) 194.9 (52.4) 7.8 (113.3) Not applicable
Lotion 4.3 (46.1) 169.3 (44.5) 5.7 (66.3) Not applicable
Cream 1.8 (32.1) Not applicable 5.7 (47.1) 1.5 (166.1)

As seen from the table, all sunscreens tested had higher blood levels than the FDA proposed threshold of 0.5 ng/mL.  These levels were also achieved on the first day of treatment.  The levels obtained triggered the FDA to request safety data not only on the sunscreens studied but also on the 12 sunscreens listed in the monograph.  In addition, the FDA requested MUsT studies to be conducted by the manufacturers on several dosage forms to establish proper guidelines for usage based on safety and efficacy.  Regardless of the results obtained, the FDA insisted on the fact that individuals should not refrain from using sunscreens.

In response to the request from the FDA, the PCPC sent a letter to describe the protocols and studies suggested by the council as well as a timeline.  The PCPC suggested to conduct, in addition to MUsT studies, several surveys on usage of sunscreen products to guide the council in designing the MUsT studies.  The timeline extends till 2023 which should give the industry some breathing room in terms of formulations.  Once the studies are received and completed, an additional timeline delineating the safety of the selected molecules will be proposed.  In the council’s response, two sunscreens were not considered for MUsT studies.  These are Cinoxate and Dioxybenzone.  The fate of these two sunscreens is not determined at this stage yet.

The sunscreen monograph has been evolving for the past 35 years to keep up with the advancement in science.  Formulators, and companies in the field of sun care will have to adjust one more time to the changes.  These changes bring a lot of new challenges and opportunities to innovate and lead.


 

Biography

Dr. Fares started his career in personal care studying the effect of solvents on sunscreen chemicals.  His interest in skin drug delivery especially from polymeric matrices grew during his graduate work at Rutgers, where he completed his Ph. D. in Pharmaceutics.

Dr. Fares worked at Block Drug and GlaxoSmithKline where he held positions in research and development in the areas of skincare and oral care.  After that, he joined L’Oreal where he held several positions of increasing responsibility leading to AVP of skincare.  He is currently the Senior Director of skincare and oral care at Ashland Specialty Ingredients.  Dr. Fares is the author of many publications, and patents and made many presentations in national and international meetings in the areas of suncare, skincare, and oral care.

 

NYSCC Suppliers’ Day Partners with Cosmetic Executive Women (CEW) on New Beauty Award for Supplier’s Innovative Ingredients and Formulation

by james.runkle@drummondst.com james.runkle@drummondst.com No Comments

All Things Beauty to Be Celebrated May 2019 in NYC

 

(New York, NY, December 2018)—The New York Society of Cosmetic Chemists  (NYSCC) has renewed its partnership with CEW by sponsoring a new category in its prestigious Beauty Awards program the “Supplier’s Award: Ingredients and Formulation.”  Mirroring the Academy Awards Science and Technical Achievement awards, the winner of the Supplier’s Award will be announced in advance at the 40th Annual Suppliers’ Day taking place May 7-8, 2019 at the Javits Convention Center in New York City. The winner of the Supplier’s Award will also be recognized at the CEW Beauty Awards luncheon on May 17th at the New York Hilton that attracts more then 3,000 attendees.

Any ingredient and formulation provider that has demonstrated innovation and new technology can submit to the CEW Supplier’s Award.  The deadline for submissions is January 15, 2019.   The submissions can only be entered from a supplier, there is no year limitation, and natural and synthetic ingredients can be entered.  For the submission form and more information click here or email: beautyawards@cew.org

A curated panel of judges from leading beauty and personal care brands including members of the NYSCC Scientific Advisory Committee will select the finalists of the “CEW Supplier’s Award: Ingredients and Formulation.”  Finalists will be announced on April 2, 2019.

“Increasingly, the line between marketing and formulation is being challenged and blurred in product development and this award highlights how all the elements and departments—ingredients, formulation and new technology—need to work together for successful product launches,” said Cathy Piterski, Chair, NYSCC.

The NYSCC Suppliers’ Day is the main trade show and conference for beauty

ingredients, formulations, and delivery innovations.  New educational programming, expanded features and enhanced industry alliances taking place at the event in 2019 include:

-“Fragrance: The Invisible Art,” an all-day, in-depth Fragrance Program, co-produced with the American Society of Perfumers featuring experts in perfume, scent, essential oils, consumer trends, and more.

 

-Spotlight on the important topic of “Safety & Testing.”  Suppliers’ Day will be collaborating with IKW, a leading European Association for German Cosmetic, Toiletry, Perfumery and Detergent, to create a program that addresses important safety and lab testing topics in the industry today.

 

-Suppliers’ Day 2019 has also added a new exhibit hall at the Javits Center, making it the largest event in the show’s history.  This hall will also feature presentation theaters and an innovation hub that will experientially complement specific theater presentations.

 

-Enhanced student engagement with an expanded Future Chemists Workshop that will include college students from Florida, Illinois and other states across the country, as well as a segment for bench chemists who are new to the industry.

 

“I am looking forward to Suppliers’ Day 2019 being the most immersive and experiential event in cosmetics chemistry and product development for our attendees.

Being our 40th Anniversary, we will also look back at the evolution of our industry over the decades and explore current trends that are elevating the importance of formulation and ingredients in beauty innovation,” said Sonia Dawson, Chair-elect, NYSCC.

For more information on NYSCC and Suppliers’ Day visit: https://nyscc.org/suppliers-day or email: suppliersday@nyscc.org.   Companies interested in exhibiting or sponsoring the NYSCC Suppliers’ Day in 2019 should contact Jane McDermott, jmcdermott@nyscc.org or call 212.786.7468.

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About New York Society of Cosmetic Chemists (NYSCC)

Dedicated to the advancement of cosmetic science, the New York Society of Cosmetic Chemists, www.nyscc.org, strives to increase and disseminate scientific information through meetings and publications. By promoting research in cosmetic science and industry, and by setting high ethical, professional and educational standards, we reach our goal of improving the qualifications of cosmetic scientists. Our mission is to further the interests and recognition of cosmetic scientists while maintaining the confidence of the public in the cosmetic and toiletries industry.  Connect with NYSCC on Twitter and Facebook at @NYSCC and Instagram: @NYSCCMAIN

 

About CEW:

CEW is an international organization of 9,000 individual members representing a cross section of beauty and related businesses. The composition of membership includes leading brands, indies, retailers, media and suppliers. CEW’s primary purpose is to provide programs online and in person to develop careers and knowledge of the beauty industry. CEW provides opportunities to connect and gain industry knowledge through networking events, trend reports, industry newsletters, interactive workshops and industry leader talks. For more information, please visit https://www.cew.org/.

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