Clean Beauty Product Formulation with Ultrasonics
Why Should You Use Ultrasonication for Your Clean Beauty Products?
Mixing, blending, dispersing, emulsifying ingredients and encapsulating bioactive molecules are core processes in the manufacturing of cosmetic, skin care, beauty and cosmeceutical products. The reliable, efficient and homogeneous execution of these core processes are essential to obtain high-quality cosmetic products with elevated effects, potency and efficiency of the final product. Modern high-tech ingredient are highly developed substances, which require sophisticated incorporation into the final product in order to get the desired effects.
Sonication – A Broad Spectrum of Applications
Sonication is a highly efficient and reliable technique of homogenizing liquid-liquid and solid-liquid suspensions. Encapsulating molecules into nano-sized lipidic carriers (e.g. liposomes, niosomes, solid-lipid nanoparticles, nanostructured lipid carriers, micelles etc.) is another important application of high-performance ultrasonics.
Ultrasonication can be applied to many steps in the production of clean, all-natural, organic cosmetic, beauty and skin care products and improve the efficiency of mixing and encapsulating applications. Since ultrasonic mixers provide intense blending and homogenization, the use of chemical additives that are commonly added to achieve prolonged stability and shelf-life can be minimized or completely avoided.
Sonication gives you a competitive advantage by producing superior outcomes in a rapid and efficient process resulting in uniform, homogeneous suspensions. This affects product stability, shelf life and biocompatibility positively.
- Mixing & Blending
- Emulsification & Nano-Emulsification
- Particle Size Reduction
- Encapsulation of Molecules (liposomes, niosomes)
- Extraction of bioactive molecules from botanicals
Sonication – A Purely Mechanical Treatment
Ultrasonification is a mild, non-thermal treatment, which does not degrade the raw materials by heat. Many ingredients such as lipids, bioactive molecules or essential oils are heat-sensitive and benefit therefore greatly by controlled low-temperature processing. Hielscher Ultrasonics devices are precisely controllable, easy adjustable and can be monitored and operated via browser emote control. The smart software automatically protocols the processing parameters on a built-in SD-card. These features facilitate process and quality standardization as well as the implementation of Good Manufacturing Practices (GMP).
The Working Principle of Sonication
Since sonication is a purely mechanical treatment, no additive chemicals, which would interfere with the philosophy of clean cosmetics, are added. Ultrasonic applications such as mixing, blending, emulsification, encapsulation and extraction are based on the working principle of acoustic cavitation.
High-power ultrasonic waves are coupled via a probe-type ultrasonic processor into the slurry. Highly energetic ultrasound waves travel through the liquid creating alternating high-pressure / low-pressure cycles, which results in the phenomenon of acoustic cavitation. Acoustic or ultrasonic cavitation leads locally to extreme temperatures, pressures, heating/cooling rates, pressure differentials and high shear forces in the medium. When cavitation bubbles implode on the surface of particles or droplets, micro-jets and interparticlular collision generate effects such as surface peeling, erosion, particle breakdown, sonoporation as well as droplet and cell disruption. Additionally, the implosion of cavitation bubbles in liquid media create macro-turbulences and micro-mixing. Ultrasonic irradiation represents an efficient way to enhance mass transfer processes, since sonication results in cavitation and its related mechanisms such as micros-movement by liquid jets, compression and decompression in the material with the subsequent disruption of droplets, as well as high heating and cooling rates.
Probe-type ultrasonicators can generate very high amplitudes, which is necessary to generate impactful cavitation. Hielscher Ultrasonic manufactures high-performance ultrasonic processors, which can easily create amplitudes of 200µm in continuous 24/7 operation. For even higher amplitudes, Hielscher offers specified high-amplitude sonotrodes (probes).
Pressurizable ultrasonic reactors and flow cells are used to intensify the cavitation. With increasing pressures, cavitation and cavitational shear forces become more destructive and improve thereby the ultrasonic effects.
Advantages of Ultrasonic Blending and Emulsification
The production of homogeneous mixtures, dispersions, emulsions, and nano-emulsions by sonification has got the interest of cosmetic formulators due to its exceptional energy efficiency, requirement of low-end mixing instruments, easy system manipulation and most importantly, its low production cost. Ultrasonic mixing, blending and emulsification increases the flexibility for selecting surfactant and internal structures of emulsions. (cf. Marzuki et al. 2019)
Molecule Size Matters
Submicron- and nano-sized molecules exhibit a significantly increased transdermal permeation rate. Whilst large molecules sit on the top of the skin and cannot penetrate the skin due to their size, smaller molecules are able to pass through the epidermis.
This means the bioactive compounds are transported into deeper dermal layers, where there they can fulfil their “work” by nourishing or repairing the skin.
A prominent example for the relevance of molecular size is hyaluronic acid, a long-chain molecule. If the hyaluronic acid has a high molcular weight, it cannot pass through the skin barrier and stays as a film on its outer layer. Low molecular hyaluronic acid on the other hand is transported into deeper skin layers, where it enfolds its moisturizing effects.
Another example for the relevance of particle size are titanium dioxide and zinc oxide. Both are used as active ingredients in natural sun screen products (e.g. lotions, moisturizers, sprays). A uniformly small particle size is important to avoid clogging the skin pores and to prevent thereby break-outs. Furthermore, with smaller particles the whitening and shining effect of sun screens is reduced or avoided.
Improved Skin Penetration
- Vesicular skin penetration enhancers include vesicular carriers such as liposomes and niosomes. Vesicular carriers are potent delivery systems for active molecules. Due to their composition, they offer the advantage of carrying hydrophilic as well as lipophilic molecules. Hydrophilic molecules are encapsulated into the aqueous core, and lipophilic molecules are incorporated into the lipid membrane surrounding the aqueous core. Since vesicle walls are comprised of phospholipid bilayers for liposomes and synthetic surfactants for niosomes respectively, the vesicles are water-soluble and thereby highly biocompatible.
Read more about ultrasonically produced liposomes!
- Enzymatic skin penetration enhancers include enzymes such as HMGCoA reductase and acetyl CoA carboxylase, which inhibit key enzymes of epidermal lipid synthesis and alter the critical molar ratio of the key stratum corneum lipids.
- Urea, also known as carbamide, is used to enhance the absorption of other active cosmetic ingredients as it increases skin permeability.
Ultrasonically Improved Bioavailability of Actives in Skin Care
The bioavailability is defined as the penetration rate for an active compound to reach its site of action. The so-called flux rate or the amount of active penetrating over time is determined in micrograms/cm2/hour. For active ingredients in cosmetic products, the target site of action for an ingredient is usually the lower epidermis. Exceptions are actives such as zinc oxide or titanium dioxide, common ingredients in sunscreen lotions and sprays, since these substances have their work site on the surface of skin, where there the particles can enfold their maximum UV absorption capacity.
The bioavailability of active ingredients is heavily influenced by the types of cosmetic formulations used. Common formulations in beauty and personal care products are oil-in-water emulsions (O/W), water-in-oil emulsions (W/O), water-in-oil-in-water emulsions (W/O/W), polyol-in-oil emulsions as well as hydrogels. (Polyols used in natural cosmetic formulations are sorbitol, mannitol, etc.).
Sonication for Increased Skin Permeability
Skin permeability and thereby bioavailability of cosmetic actives and cosmeceuticals can be increased by either influencing the skin barrier or by increasing the solubility of the active molecules.
In order to lower the skin barrier and facilitate the transport of the active molecules into the lower epidermis, manifold substances such as solvents, phospholipids and surfactant vesicles made from phospholipids as well as exfoliants can improve the penetration of actives into deeper skin layers.
- Solvents used include dimethyl isosorbide, ethoxydiglycol, ethanol, and oleic acid. These solvents are highly compatible with ultrasonic mixing, blending and emulsification processes.
- Phospholipids are well known to enhance skin penetration of both oil- and water-soluble molecules. Commonly used phospholipids are lecithin, hydrogenated lecithin, lysolecithin, and tocopheryl phosphate. They benefits from ultrasonic processing as sonication distributed the phospholipids evenly into the suspension.
- Surfactant vesicles: Surfactants can form multilamellar and unilamellar vesicles with actives. Liposomes and solid-lipid nanoparticles are prominent examples for skin penetrating vesicles transporting bioactive compounds to target sites. Ultrasonication is the most efficient and effective method to produce liposomes, nanoliposomes and solid-lipid nanoparticles (SLNs) with a high active load, encapsulation efficiency (%EE), stability and bioavailability.
- Chemical exfoliants include lactic, glycolic, salicylic acids, and N-acetyl-glucosamine. Mechanical peelings include minuscule abrasive particles from charcoal, coconut flakes or coffee scrub. All these substances can be efficiently dispersed via ultrasonification.
Solubility of active ingredients in cosmetics can be increased by inclusion complexes, encapsulation, sub-micron-/nano-emulsions as well as the efficient solubilisation into the formulation.
- Inclusion complexation using cyclodextrins (such as alpha-, gamma-, hydroxypropyl beta-cyclodextrin) is achieved by ultrasonication. Cyclodextrin complexes exhibit a cavity in which bioactive ingredients are encapsulated. The encapsulation / complexation makes the active compounds water-soluble and thereby bioavailable. Read more about ultrasonic infusion complexation!
- Phytoglycogen is a plant-based, high-density carbohydrate (polysaccharide) nanoparticle with a cavity which can encapsulate many different types of actives. Phytoglycogen octenyl succinate (PG-OS) is an amphiphilic carbohydrate nanoparticle, whose addition gives emulsions a high lipid oxidative stability. Ultrasonic emulsification improves the generation of homogeneous, stable phytoglycogen emulsions.
- Submicron- and nanoemulsions are used as minute delivery systems, which make the compounds water-soluble and allow to transport the active ingredients to the target site. The small nano-scale size of the droplets increase the permeability through the skin barrier into deeper skin layers.
- Highly polar emollients are commonly used in formulations to solubilize hydrophobic / water-insoluble ingredients as only few active substances are non-polar. Frequently used are the following highly polar emollients: isopropyl lauroyl sarcosinate, lauryl lactate, phenyl ethyl benzoate, dioctyl maleate, and dioctyl isosorbide. Various types sunscreens are known to be penetration enhancers, too. Ultrasonic mixing and dispersing ensures a homogeneous mixture of polar emollients and active ingredients.
High-Performance Ultrasonic Mixers for Clean Beauty Products
As purely mechanical mixing treatment, sonication can used for the production of all kinds of certified natural cosmetic products. Hielscher Ultrasonics’ systems are reliable machines used in the production of high quality cosmetics and therapeutics to formulate nano-emulsified and liposomal encapsulated bioactive compounds with superior absorption rate and biocompatibility. To meet its customers’ demands, Hielscher supplies ultrasonicators from the compact hand-held lab homogenizer and bench-top ultrasonicators to fully industrial ultrasonic systems for the production of high-volumes of cosmetic formulations. Ultrasonic formulation processes of cosmetics and cosmeceuticals can be run as batch or as continuous inline process using an ultrasonic flow-through reactor. A broad range of ultrasonic sonotrodes (probes) and reactor vessels are available to ensure an optimal setup for your liposome production. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation under heavy duty in demanding environments and ensure a long machine life cycle.
The precise control over all important process parameters such as amplitude, pressure, temperature and sonication time make the ultrasonic process reliable and reproducible. Hielscher Ultrasonics knows of the importance of continuously high product quality and supports cosmetic manufacturers to implement process standardisation and GMP (Good Manufacturing Practices) by intelligent software and automatic data recording. Our digital ultrasonic homogenizers automatically record all ultrasonic process parameters on a built-in SD-card. Digital touch displays and browser remote control allow for continuous process monitoring and enable to adjust the process parameters precisely whenever required. This facilitates process monitoring and quality control significantly.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
|Batch Volume||Flow Rate||Recommended Devices|
|1 to 500mL||10 to 200mL/min||UP100H|
|10 to 2000mL||20 to 400mL/min||UP200Ht, UP400St|
|0.1 to 20L||0.2 to 4L/min||UIP2000hdT|
|10 to 100L||2 to 10L/min||UIP4000hdT|
|n.a.||10 to 100L/min||UIP16000|
|n.a.||larger||cluster of UIP16000|
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Literature / References
- Kentish, S.; Wooster, T.; Ashokkumar, M.; Simons, L. (2008): The use of ultrasonics for nanoemulsion preparation. Innovative Food Science Emerging Technologies 9(2):170-175.
- Zahra Hadian, Mohammad Ali Sahari, Hamid Reza Moghimi; Mohsen Barzegar (2014): Formulation, Characterization and Optimization of Liposomes Containing Eicosapentaenoic and Docosahexaenoic Acids; A Methodology Approach. Iranian Journal of Pharmaceutical Research (2014), 13 (2): 393-404.
- Joanna Kopecka, Giuseppina Salzano, PharmDa, Ivana Campia, Sara Lusa, Dario Ghigo, Giuseppe De Rosa, Chiara Riganti (2013): Insights in the chemical components of liposomes responsible for P-glycoprotein inhibition. Nanomedicine: Nanotechnology, Biology, and Medicine 2013.
- Harshita Krishnatreyya, Sanjay Dey, Paulami Pal, Pranab Jyoti Das, Vipin Kumar Sharma, Bhaskar Mazumder (2019): Piroxicam Loaded Solid Lipid Nanoparticles (SLNs): Potential for Topical Delivery. Indian Journal of Pharmaceutical Education and Research Vol 53, Issue 2, 2019. 82-92.
- Kiran A. Ramisetty; R. Shyamsunder (2011): Effect of Ultrasonication on Stability of Oil in Water Emulsions. International Journal of Drug Delivery 3, 2011. 133-142.
- Shabbar Abbas, Khizar Hayat, Eric Karangwa, Mohanad Bashari, Xiaoming Zhang (2013): An Overview of Ultrasound-Assisted Food-Grade Nanoemulsions. Food Engineering Reviews 2013.
- Ng Sook Han, Mahiran Basri, Mohd Basyaruddin Abd Rahman, Raja Noor Zaliha Raja Abd Rahman, Abu Bakar Salleh, Zahariah Ismail (2012): Preparation of emulsions by rotor–stator homogenizer and ultrasonic cavitation for the cosmeceutical industry. Journal of Cosmetic Science 63, September/October 2012. 333–344.
Facts Worth Knowing
What are Clean Beauty Products?
Clean beauty cosmetics are beauty products, which are made of non-toxic, naturally occurring ingredients. Whilst organic or natural cosmetic is not a uniformly defined and protected term, natural cosmetic focusses on the use of natural, organically grown raw materials. Substances that might be harmful (e.g. endocrine disruptors) are excluded from clean cosmetic products, whilst the purity of the used raw materials is an important quality factor.
According to a definition widely recognised in the European Union, natural cosmetics are products that are made from natural substances. For preservatives and emulsifiers contained in natural cosmetic products, this definition is partly stretched. Natural substances are defined as substances of plant, animal or mineral origin as well as their mixtures and reaction products with each other. For the extraction and further processing only physical / mechanical processes, such as mechanical agitation, drying, filtering and extraction with specified solvents is allowed. In addition, enzymatic and microbiological processes are permitted if only natural enzymes or microorganisms that are not genetically engineered (non-GMO) are used.
Organic and natural cosmetics include beauty and skin care products that are made exclusively of natural substances and derivatives or permitted substances for preservation. Natural / organic beauty and skin care products are subject to the same legal regulations as other cosmetics.
These ingredients (INCIs / International Nomenclature Cosmetic Ingredients) are commonly used and preferred raw materials used in clean beauty formulations:
- Solvents: water phase: aqua, infused water such as rose water etc.; organic ethanol; vegetable glycerin etc.
- Surfactants / stabilizers / emulsifiers: lecithin, phospholipids; glucosides such as lauryl glucoside, decyl glucoside, caprylyl / decyl glucoside, coco glucoside; cocamidopropyl betaine; cetearyl alcohol, etc.
- Carrier oils / oil phase: oils and butters such as sweet almond oil, avocado oil, walnut oil, coconut oil, hemp oil, sunflower seed oil, castor oil, organ oil, broccoli seed oil, black seed oil, carrot oil, baobab seed oil, etc.
- Butters and waxes: shea butter, coconut butter, mango butter, cocoa butter, organic bee wax, etc.
- Botanical extracts such as chamomile water, arnica flower extract, calendula extract, burdock root extract, rose water, prime rose seed extract, nettle tincture, papaya glycerol extract, etc.
- Natural essential oils such as lavender, peppermint, tea tree, rosehip, menthe (essential oils used in natural cosmetic products must be extracted from natural raw material, not artificially synthsized)
- Active ingredients are the substances which make cosmetic products actually work, i.e. gives them their moisturising, rejuvenating & anti-aging effects. Active ingredients / bioactive molecules such as resveratrol, hyaluronic acid, urea, vitamin C, CoQ10, ceramides, vitamin E / alpha-tocopherol, B vitamins, ferulic acid, retinol & retinoids, peptides, titanium dioxide, zinc oxide, activated charcoal, natural lactic acid, pyrrolidone carboxylic acid, mineral salts, D-panthenol, grape extract, olive leaf extract, aloe vera, oligogalactomannans etc.
- Fragrances and perfume ingredients used in natural cosmetics are mostly essential oils, natural oils and specific aroma compounds. Essential oils from orange, lavender, peppermint, lemon, sandalwood, jasmine, neroli, patchouli, rose, and ylang-ylang are popular fragrance ingredients in natural cosmetic products.
Ultrasonic extraction is the superior method to produce high quality essential oils from botanicals. Read more about ultrasonic hydrodistillation of essential oils!
Common Active Ingredients in Natural Cosmetic Products
Panthenol is a substance, that occurs in nature known as pro-vitamin B5, and is used in cosmetic products material as emollient and moisturizing agent. In hair care formulations it is added as humectant, emollient, glossifier, detangler and moisturizing agent. Panthenol is available as D form, or as a racemic mixture, the DL-panthenol. D-panthenol is the preferable form, since only D-panthenol is converted to Vitamin B5.
Polyphenols such as resveratrol, quercetin, and rutin are potent natural antioxidants, which can be extracted from botanicals. They are used in cosmetics and cosmeceuticals to inhibit oxidative chain reactions in human skin and support therefore overall skin health and can prevent some skin diseases as well as premature ageing.
Certified Natural Cosmetics
There is no single globally valid certification standard for organic natural beauty and cosmetic products. Cosmetic manufacturers can get their products certified in accordance with different certification standards, which are accepted in specific countries or regions.
A prominent and internationally recognised certification is the COSMOS-standard (COSMetic Organic Standard) that distinguishes between natural cosmetics (Cosmos-natural) and organic cosmetics (Cosmos-organic) and sets the respective requirements for certification. A cosmetic care product is COSMOS ORGANIC certified only if 95% minimum of the plants it contains are organic and at least 20% of organic ingredients are present in the total formula (10% for rinse-off products).