Knowledge Base
Unlike Newtonian fluids, non-Newtonian fluids possess shear-rate dependent viscosities. In addition to shear-rate dependent viscosities, non-Newtonian
fluids also exhibit elastic stresses when subjected to high shear rates. The usefulness of the elastic response varies with application.
At low shear rates, i.e., near at rest conditions, non-Newtonian fluids exhibit high viscosities that are relatively insensitive to shear rate and characterized by zero shear viscosity. The zero shear viscosity is known to be highly sensitive to the molecular weight and concentration of the rheological additives. The rates of deformation associated with this region include sedimentation and levelling forces, and one can tailor the zero shear viscosity to combat these forces. At moderate shear rates the decrease in viscosity versus shear rate helps when pouring and pumping these fluids. At high shear rates it is found that a second Newtonian plateau in viscosity is reached usually characterised by the so-called infinite viscosity. The shear forces in this area are close in magnitude to forces developed during rubbing and spraying exercises. The low viscosities exhibited by the rheological additives in this region imply low resistance to rubbing and thus a smooth sensation of the substance during its application.
Source: Handbook of Cosmetic Science and Technology - André O. Barel, Marc Paye, Howard I. Maibach
The viscosity of fluids can be modified by addition of particulates that may strictly change the viscosity index. When non-interacting buoyant particles are used in these
fluids, the viscosity of the dispersion can be predicted using the Einstein relation. Examples of such rheology-modifying substances include silica gels, fumed silica, carbon black, titanium dioxide and aluminum-magnesium-stearates when used at very small concentrations. Low molecular weight polymers also fit in this category and may be preferred if a smooth or fluid like formulation is desired.
Source: Handbook of Cosmetic Science and Technology - André O. Barel, Marc Paye, Howard I. Maibach
The Food and Drug Administration (FDA) includes Niacinamide and Niacin on its list of direct food substances affirmed as Generally Recognized As Safe (GRAS). Both ingredients are also GRAS as nutrients and/or dietary supplements. The safety of Niacinamide and Niacin has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the available scientific data and concluded that Niacinamide and Niacin were safe in the current practices of use and concentration in cosmetics and personal care products. Niacinamide (aka nicotinamide) and Niacin (aka nicotinic acid) are heterocyclic aromatic compounds which function in cosmetics primarily as hair and skin conditioning agents. Niacinamide is used in around 30 cosmetic formulations including shampoos, hair tonics, skin moisturizers, and cleansing formulations. Niacin is used in a few similar product types. The concentration of use of Niacinamide varies from a low of 0.0001% in night preparations to a high of 3% in body and hand creams, lotions, powders and sprays. Niacin concentrations of use range from 0.01% in body and hand creams, lotions, powders and sprays to 0.1% in paste masks (mud packs). Both ingredients are accepted for use in cosmetics in Japan and the European Union. Both are GRAS direct food additives and nutrient and/or dietary supplements. Niacinamide may be used in clinical treatment of hypercholesteremia and Niacin in prevention of pellegra and treatment of certain psychological disorders. Both ingredients are readily absorbed from skin, blood, and the intestines and widely distribute throughout the body. Metabolites include N1-methylnicotinamide and N1-methyl-4-pyridone-3-carboxamide. Excretion is primarily through the urinary tract. While Niacinamide is more toxic than Niacin in acute toxicity studies, both are relatively non-toxic. Short-term oral, parenteral, or dermal toxicity studies did not identify significant irreversible effects. Niacinamide, evaluated in an in vitro test to predict ocular irritation, was not an acute ocular hazard. Animal testing of Niacinamide in rabbits in actual formulations produced mostly non-irritant reactions, with only some marginally irritating responses. Skin irritation tests of up to 2.5% Niacinamide in rabbits produced only marginal irritation. Skin sensitization tests of Niacinamide at 5% during induction and 20% during challenge were negative in guinea pigs. Neither cosmetic ingredient was mutagenic in Ames tests, with or without metabolic activation. Niacinamide and Niacin at 2 mg/ml were negative in a chromosome aberration test in Chinese hamster ovary cells, but did produce large structural chromosome aberrations at 3 mg/ml. Niacinamide induced sister chromatid exchanges in Chinese hamster ovary cells, but Niacin did not. Under certain circumstances, Niacinamide can cause an increase in unscheduled DNA synthesis in human lymphocytes treated with UV or a nitrosoguanidine compound. Niacinamide itself was not carcinogenic when administered (1%) in the drinking water of mice. No data on the carcinogenic effect of Niacin were available. Niacinamide can moderate the induction of tumors by established carcinogens. Niacinamide in combination with streptozotocin (a nitrosourea compound) or with heliotrine (a pyrrolizidine alkaloid), produced pancreatic islet tumors. On the other hand, Niacinamide reduced the renal adenomas produced by streptozotocin; and intestinal and bladder tumors induced by a preparation of bracken fern. Niacinamide evaluated in in vitro test systems did affect development, but Niacinamide reduced the reproductive/developmental toxicity of 2-aminonicotinamide-amino-1,3,4-thiadiazole hydrochloride and urethane. Clinical testing of Niacinamide produced no stinging sensation at concentrations up to 10%, use tests produced no irritation at concentrations up to 5%, and a 21-day cumulative irritation test at concentrations up to 5% resulted in no irritancy. Niacinamide was not a sensitizer, nor was it a photosensitizer. The CIR Expert Panel considered that Niacinamide and Niacin are sufficiently similar from a toxicologic standpoint to combine the available data and reach a conclusion on the safety of both as cosmetic ingredients. Overall, these ingredients are non-toxic at levels considerably higher than would be experienced in cosmetic products. Clinical testing confirms that these ingredients are not significant skin irritants, sensitizers or photosensitizers. While certain formulations were marginal to slight ocular irritants, other formulations were not. Niacinamide, while not carcinogenic alone, can modulate the induction of tumors by certain established carcinogens. The Panel noted that the doses in these studies are high relative to the low concentrations at which Niacinamide is used in cosmetic formulations. In neither case (tumor protection or tumor promotion) are these findings considered relevant to the use of Niacinamide at its current low concentrations of use in cosmetics. Both ingredients were considered safe as used in cosmetics.
Source: Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5)
When choosing your bottle you will need to decide which neck best suits your products and choice of cap. This number is the neck finish.
The neck finish is normally signified by two numbers - for example 20/410, 20/415, 24/410 ans 24/415. These two numbers represent the outer diameter of the neck opening (mm), the thread configuration and height of the neck.
A natural is any material that is harvested, mined, or collected, and which may have subsequently been washed, decolorized, distilled, fractionated, ground, milled, separated, or concentrated, leaving a chemical or chemicals that would be available and detectable in the original source material. It is also the modification of natural material by the action of microorganisms, enzymes, or yeasts to modify or increase the yield of material by this process. Naturally derived materials are defined by the use of a natural raw material as the starting point in a chemical process that produces a new chemical or chemicals that in themselves may not be available in nature or in the starting material. Nature-identical materials are substances that have been synthetically produced, not usually from a natural starting material, in order to produce a material that is identical to that naturally occurring in nature.
Source: Dermatologic, Cosmeceutic and Cosmeticdevelopment - Kenneth A. Walters, Michael S. Roberts
What is a nanomaterial?
A nanomaterial is a material in which at least one external dimension is in the nanoscale range (1-100 nanometers). Nanomaterials exhibit unique properties that are different from their bulk counterparts due to their small size. These properties arise from the increased surface area, quantum confinement, and enhanced reactivity of nanomaterials.
Despite the many potential benefits of nanomaterials, there are also some concerns about their safety. Nanomaterials can be inhaled, swallowed, or absorbed through the skin, and they may pose a risk to human health. More research is needed to assess the potential risks and benefits of nanomaterials.
Nanomaterials in cosmetics
In the context of cosmetics, a nanomaterial is defined as an intentionally manufactured material with at least one external dimension or an internal structure in the nanoscale range (1-100 nanometers). This means that the material is so small that it can only be seen with an electron microscope.
Nanomaterials are being increasingly used in cosmetics due to their unique properties, such as their ability to:
- Improve the efficacy of cosmetic products: Nanoparticles can be used to deliver active ingredients deeper into the skin, making them more effective.
- Increase the stability of cosmetic products: Nanoparticles can help to stabilize active ingredients and protect them from degradation.
- Enhance the aesthetic properties of cosmetic products: Nanoparticles can be used to improve the texture, color, and fragrance of cosmetic products.
Definition of nanomaterials:
Regulation (EC) No 1223/2009 specifically covers the use of nanomaterials in cosmetic products. The Regulation provides a definition of nanomaterial, as well as a mechanism for notification, labelling, and safety evaluation of cosmetic products containing nanomaterials. Under Article 2 (1) (k), “nanomaterial” means an insoluble or bio persistent and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm”. In view of the EU Chemicals Strategy for Sustainability (Ares, 2021), it is likely that the definition for a nanomaterial in the Cosmetic Regulation will be aligned with the recently published 2022/C 229/01 Commission Recommendation of 10 June 2022 on the definition of nanomaterial. The Regulation therefore mainly covers those nanomaterials that are intentionally produced and are insoluble/poorly-soluble or bio persistent (e.g., metals, metal oxides, carbon materials, etc.), and not those that are either completely soluble or degraded and are not persistent in biological systems (e.g., liposomes, oil/water emulsions, etc.). When dealing with the question of solubility, as provided in the current definition, it is important to note that any nano-specific risk may change (even diminish) when a nanomaterial is dissolved. But it is the time period during which the dissolution happens that determines the considerations for risk assessment based on either particle risk or soluble substance risk. Partial dissolution over a long period of time may lead to the mistaken claim that the material is 'soluble', and therefore not a nanomaterial under the scope of the current definition provided in the Cosmetic Regulation (EC) No 1223/2009.
Potential safety issues of nanomaterials
The use of nanomaterials in cosmetics is subject to a high level of protection of human health under the EU Cosmetics Regulation. This is because nano forms of some substances may differ from their conventional (bulk) forms in terms of physicochemical properties, biokinetic behaviour, and/or biological effects. Any intended use of nanomaterials (other than colourants, preservatives and UV filters and not otherwise restricted by the EUCosmetics Regulation) in cosmetic products must be notified to the Commission by the RP through the Cosmetic Product Notification Portal (CPNP) at least six months prior to placing them on the market, except if they were already on the market before 11 January 2013.In case of a safety concern over a nanomaterial, the Commission shall request the SCCSfor a scientific Opinion on the safety of the nanomaterial for use in relevant categories of cosmetic products in consideration of the reasonably foreseeable consumer exposure.The SCCS was recently mandated by the Commission to provide scientific advice to facilitate the identification of any safety concerns relating to the nanomaterials intended for use in cosmetic products, so that they can be prioritised for safety assessment. The advice has recently been published (SCCS/1618/2020), which provides the key scientific aspects of a nanomaterial that should trigger consumer safety concerns, and therefore the need for further evidence-based safety assessment.Although there are currently no hard and fast rules for identifying the safety concerns for nanomaterials, as a general principle, each of the following attributes should add a further degree of safety concern. For example, where:
i. The nanomaterial has constituent particles that have sizes in the lower range of the nanoscale.
ii. The nanomaterial is insoluble, or only partially soluble.
iii. The chemical nature of the nanomaterial suggests the potential for a toxicological hazard.
iv. The nanomaterial has certain physical/morphological features (e.g. needle shape, rigidlong fibres) that are associated with a higher potential for harmful effects. The nanomaterial has surface reactivity in terms of catalytic (including photocatalytic)activity, potential for radical formation, or other surface properties (e.g. potential allergenicity due to proteinaceous surface).
v. The nanomaterial has a different bio kinetic behaviour than the conventional equivalent.For example, a surface modification/coating (e.g. hydrophobic coatings, encapsulation)has been applied to core nanoparticles to alter their ADME properties and as a result make them more accessible systemically, compared to the neat nanoparticles and/or their conventional chemical forms.
vi. The nanomaterial is used as vehicle to carry other substances that have not been assessed for safety as individual components, or together in the form of nano-scale entity.
vii. There is a likelihood of systemic exposure of the consumer to nanoparticles through the use of final products. The frequency of use, and/or the amounts of the relevant consumer product are relatively high.
viii.There is evidence for persistence/accumulation of nanoparticles in the body.
ix. Nanoparticles have other distinctive properties not present in conventional form of the same material, or have a new activity/function (e.g. a smart/functional nanomaterial).
x. The nanomaterial is so novel that it does not have a conventional comparator to allow assessment of changes in properties, behaviour or effects.
xi. The nanomaterial is used in a product that is inhalable (taken up by inhalation into respiratory tract and lung), and the particles are respirable (can reach respiratory epithelium i.e. alveoli).
xii. The assessment of genotoxicity is performed inadequately, e.g. in vitro studies are without information on stability of the test suspension, or evidence of cell exposure(internalisation).
While this section only provides a brief guidance on nanomaterials in cosmetics, the SCCS has published a more detailed specific Guidance on Risk Assessment of Nanomaterials( SCCS/1611/19, under revision), which is an update of a previous guidance published in2012 (SCCS/1484/12), a Memorandum on the Relevance, Adequacy and Quality of theData Expected in Safety Dossiers on Nanomaterials (SCCS/1524/13), and a checklist for the applicants submitting dossiers on nanomaterials as cosmetic ingredients(SCCS/1588/17). Safety assessors need to consult these documents to ensure that any testing to generate evidence on the safety of nanomaterials is carried out with special considerations of the nano-size related characteristics of the materials, and in compliance with the ban on animal testing of cosmetic ingredients. In this regard, it is important to note that, as indicated in the memorandum (SCCS/1524/13), the SCCS will only consider data that are relevant to the nanomaterial(s) under evaluation, are sufficiently complete, and are of appropriate quality to support the safety assessment. The SCCS has also published a number of scientific Opinions in the past few years on the nano-form of different materials. Each of the Opinions can be consulted via the EuropeanCommission website. SCCS Opinions can provide further information on the type o fscientific evidence needed in a safety dossier on nanomaterials intended for use as cosmetic ingredients.In general, a number of reviews have concluded that the existing risk assessment paradigm, in use for conventional chemicals, should in principle be also applicable to engineered nanomaterials. However, it has also been pointed out that the current testing methods may need certain adaptations to take account of the special features of nanomaterials (Rocks et al., 2008; SCENIHR, 2009; SCCS, 2012; EC, 2012; ECHA, 2017; EFSA, 2018;EFSA, 2021a, EFSA 2021b, EC 2022).
Special features of nanomaterials:
- Due to high surface energies, nanoparticles have a tendency to stick together to form agglomerates and aggregates, and/or bind with other moieties on the particle surface.This particle behaviour can change in the presence of certain stabilising/dispersing agents. Characterisation of nanomaterials, prior to and during a test, is therefore a key to ensuring that results obtained are valid.
- Most of the currently available test methods were developed for conventional substances that can be solubilised. In contrast, nanomaterials generally comprise insoluble or poorly soluble nanoparticles that are dispersed in a test medium in the form of a nano-suspension rather than a solution. The applied concentration of a nanomaterial may therefore drop during the test due to particle agglomeration, sedimentation, binding with other moieties in the medium, or sticking to the sides ofthe glass/plastic ware. This could lead to only a partial or no exposure of the test systems during the test. Nanomaterials are known to adsorb or bind different substances on their surfaces, including proteins (Šimon and Joner, 2008; Lynch andDawson, 2008; Monopoli et al., 2012; Moore et al., 2015). They may also bind other substances in the test medium and carry them into the exposed test systems, leading to artefacts in the results.
- The toxicological hazards of chemical substances are currently measured and expressed in terms of weight or volume units (such as mg/kg, or mg/l). These conventionalmetrics may not be fully adequate to account for nanomaterial toxicity. It is thereforeimportant that tests on nanomaterials are not only evaluated in terms of weight/volume concentration, but that results are also expressed in other dose-describing metrics, such as particle number concentration, surface area etc.
- Due to the insoluble particulate nature, and the nano-dimensions, nanomaterials may show an altered uptake and bio kinetic profile in a biological system compared to equivalent conventional forms, e.g. transport of insoluble particles across biological membrane barriers is not driven by concentration-gradient based diffusion partitioning, but by other mechanisms such as endocytosis and/or active (energy-driven) uptake and transport.
- Currently, there are uncertainties in regard to whether the endpoints identified by the current testing methods will be sufficient to identify and characterise all the hazards that may be associated with a nanomaterial.
Source: SCCS Notes of guidance for the testing of cosmetic ingredients and their safety evaluation
MSDS stands for Material Safety Datasheet. This document provides detailed information about the properties, hazards, handling, storage, and emergency measures related to a chemical product or substance. MSDSs are typically created by manufacturers, suppliers, or distributors of chemicals to ensure that users, such as workers, emergency responders, and consumers, have access to important safety information.
Microneedles are a promising and minimally invasive transdermal delivery technique effective in promoting peptide permeation through the skin.
The needles have a size ranging from 100 to 1500 μm, which makes them able to pass through the stratum corneum (thickness between 10 and 30 μm).
Furthermore, they are responsible of forming pores in the skin, which are large enough to allow macromolecules to pass through, simply and painlessly.
Despite the advantages of this notable approach, microneedles have an obstacle when it comes to the delivery of substances: the elasticity of the skin. This parameter may hinder the penetration of microneedles in the stratum corneum, since the skin, can deform with the pressure exerted by the needle, without breaking its barrier. Consequently, pore formation and substance permeation are compromised.
There are some studies suggesting that different microneedles allow successful permeation of peptides into the skin. An in vitro study was performed by Zhang et al., to investigate the efficacy of solid microneedle arrays (consisting of 121 needles, attached to an applicator) in delivering hydrophilic peptides, namely acetyl hexapeptide-3, into pig ear skin. The results of the study exhibited not only that this physical system was effective in forming pores, but also in the delivery of the peptides through the skin, since the passive flow of acetyl hexapeptide 3 through the skin, when microneedles were applied was 0.44 ± 0.12 μmoL/cm/h, which was much higher than the passive flow of this peptide in untreated skin (0.014 ± 0.002 μmoL/cm/h).
Source: Journal of Drug Delivery Science and Technology - Anti-aging peptides for advanced skincare: Focus on nanodelivery systems
Microplastics are tiny pieces of plastic that measures less than five millimeters in size. Some microplastics are formed by breaking away from larger plastics that have fragmented over time. Others are made intentionally small, otherwise known as microbeads. These are also used in cosmetics products such as face scrubs, as well as detergents, paints, medicines, nappies and pesticides. The use of microbeads in cosmetics is banned in the EU.
Minimum order quantity is a requirement from some manufacturers for the minimum number of orders to be purchased at one time. This is required in order for manufacturers to remain profitable, as often they work on smaller margins and require large order volumes to generate enough revenue to maintain their business.
The MOQ is typically between 5 to 10,000 pieces for custom cosmetic packaging, and for cosmetic RAW materials, it varies between 1 to 50 kgs, depending on the supplier of the ingredient. Contract manufacturers also have an MOQ, which typically ranges from 2,000 to 10,000 pieces, depending on the manufacturer.
The term ‘mineral oil’ refers to very highly refined liquid hydrocarbons derived from petroleum distillates, which are used in medicine, pharmaceuticals, cosmetics, food packaging, food contact applications and food itself. Other terms often used interchangeably with mineral oil, include ‘liquid petrolatum’, ‘liquid paraffin’, ‘paraffin oil’, ‘medicinal oil’, ‘white oil’, ‘white mineral oil’, ‘food grade oil’, ‘food grade white oil’ and ‘technical white oil’. Mineral oils (medium and low viscosity) are manufactured from crude mineral oils in various refining steps, such as distillation, extraction and crystallization, and are subsequently purified by acid treatment (oleum method) and/or hydrotreatment (catalytic hydrogenation). Mineral oils (medium and low viscosity) are mixtures of highly refined paraffinic and naphthenic liquid hydrocarbons with boiling points greater than 200°C. They are lightweight, inexpensive, odourless and tasteless. Mineral oils are a common ingredient in baby lotions, cold creams, ointments and cosmetics. Examples are their use to prevent brittleness and breaking of eyelashes, in cold cream, and to remove make-up and temporary tattoos. A common concern regarding mineral oil is the presence in many lists of comedogenic (i.e. clogs skin pores) substances that were developed many years ago and are frequently quoted in the dermatological literature. However, more recently, highly refined and purified oils commonly used in cosmetics and skin care products are non-comedogenic.
Source: Cosmetic Formulation Principles and Practice - Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters
Microemulsion is defined as a system of water, oil, and amphiphile, which is a single optically isotropic and thermodynamically stable liquid solution. ‘‘This definition should be widened, however, to include metastable states, spontaneous emulsions of long-lived kinetic stability.’’ The term microemulsion may be a misnomer, because microemulsions consist of large or ‘‘swollen’’ micelles containing the internal phase, much like that found in a solubilized solution.
Microemulsions contain oil droplets in a water phase or water droplets in oil with diameters of about 10 to 200 nm. Therefore they appear as isotropic, optically clear liquid or gel-like systems. Unlike micellar solubilized systems, microemulsions may not be thermodynamically stable; nevertheless, they are more stable than ordinary emulsions. They are a type of ternary system composed from water, lipid, and surfactant mixture in a distinct ratio
Microemulsions may be used to incorporate or dissolve active substances and have been found to improve skin penetration and permeation.
The disadvantage of microemulsions is their rather high concentration of surfactants, which is a risk for increased skin irritation and sensitization. Nevertheless, modern microemulsion formulation is based on alkyl polyglycosides which are regarded to be milder than conventional nonionic surfactants with polyoxyethylene chains.
Hydrogels are hydrophilic, consisting mainly (85–95%) of water or an aqueous-alcoholic mixture and the gelling agent.
Source: Handbook of Cosmetic Science and Technology - André O. Barel, Marc Paye, Howard I. Maibach
Peppermint. Country: South Africa/Malawi. Part used: fresh leaves. Traditional use: Typical minty fragrance with mentholic undertones. It has a clean, clearing, penetrating odor. Invigorating; ideal travel companion, calms the stomach. Used to bathe tired and sweaty feet. A good insect repellent. Has a cooling effect on the body. Stimulating, used for headaches and nausea, very cooling. Breath freshener.
Source: Handbook Of Natural Ingredients - Anthony C. Dweck
A spherical conglomeration of surface active molecules formed in solution. The polar groups on the molecules align toward the water phase and the nonpolar groups tend to point toward the oil or nonpolar phase. This phenomenon allows groups of molecules to form spherical cells. Micelle formation is the basis for most emulsification. Liposomes are a form of micelles.
The diameter of a Micelle particle ranges from 5 to 100 nm.
The size and shape of micelles can vary depending on the type of surfactant and the conditions in the solution.
Micelles can be either spherical or rod-shaped.
Micelles can be used to solubilize a variety of different substances, including oils, fats, and drugs.
Micelles can also be used to stabilize emulsions and foams.
Microcrystalline wax is a solid obtained by extracting the oil from petrolatum. It is a complex mixture composed mainly of C31–C70 isoparaffins. It has a microcrystalline structure, high adhesive power, good extensibility, is not susceptible to low temperatures and has a high melting point (60–85°C). When mixed with other waxes, it suppresses crystal formation making it useful in lipsticks and creams.
Source: Cosmetic Formulation Principles and Practice - Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters
Melasma manifests as increased pigmentation in the face, typically symmetric patches or macules are found on either side, with a tendency to occur on the sunexposed
areas of the face (cheeks, upper lips). This disorder is much more common in women than men (a ratio of 9:1) and in persons with high-grade phototype.
Major etiologic factors include genetic influences, female sex hormones, and exposure to UV radiation. Histopathology findings indicate hyperpigmentation in all epidermal layers caused by an increase in melanin and also the number of active melanocytes. A flattening of the epidermal rete ridges has been reported, suggesting that keratinocytic proliferation may not be involved in melasma. Pathogenesis is poorly understood. A recent study indicated that the high expression of α-MSH in keratinocytes of the melasmic lesions was a major factor. Treatment options are prevention using good broad-spectrum sunscreen, retinoids, α-hydroxy acids, and hydroquinone.
Source: Dermatologic, Cosmeceutic and Cosmetic development - Kenneth A. Walters, Michael S. Roberts
Letterpress printing in commercial printing, process by which many copies of an image are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. Letterpress is the oldest of the traditional printing techniques and remained the only important one from the time of Gutenberg, about 1450, until the development of lithography late in the 18th century and, especially, offset lithography early in the 20th.
Originally the ink-bearing surface for printing a page of text was assembled from individual types by a typesetter or compositor, letter by letter and line by line. The first keyboard-actuated typesetting machines, the Linotype and the Monotype (qq.v.), were introduced in the 1890s. If only a small number of copies is to be made, printing can be done directly from the hand- or machine-set blocks of type assembled in forms, but for long press runs, duplicates—stereotypes or electrotyping (qq.v.)—are made to prevent wear and damage of the expensive types.
Letterpress was originally carried out on platen presses, in which the paper is pressed against the flat, inked form by a flat platen; later, the platen was replaced by a roller in the flat-bed cylinder press; still later, the printing form was wrapped around one cylinder and the paper was passed between this cylinder and a second, creating a rotary press (see printing).
Letterpress can produce work of high quality at high speed, but it requires much time to adjust the press for varying thicknesses of type, engravings, and plates. Because of the time needed to make letterpress plates and to prepare the press, many newspapers have changed to offset printing. To combat this trend, letterpress printers have developed printing plates made from a photosensitive plastic sheet that can be mounted on metal.
Source: Britannica.com
Mango is a tree that grows up to 40 m in height. It originates from the regions of Bangladesh, Myanmar, India and Indonesia. It is one of the most exploited tropical trees, both in its native regions and in Africa, Australia and South America, where the tree is grown commercially. Botanical characteristics: bark greyish brown or black; leaves smooth, initially red, but become dark green during growth, lanceolate; inflorescence paniculate, flowers small, greenish white or pink, in groups of 500 to 6,000, petals 5, stamens 5, sepals 5, pubescent; fruits botanically termed drupes, oblong, 8 to 12 cm long, exocarp smooth, greenish yellow or greenish red, mesocarp fleshy, juicy, yellow, endocarp hard, with 1 large seed.
Mango seeds contain 9 to 13% butter. Its triglyceride composition is characterised by the balanced proportion of predominant stearic and oleic acids. Another important feature is its content of phytosterols, which may be as high as 7%. The melting point is approximately 35°C. Mango butter is stable against oxidation. It is of yellow or light-brown colour and has a typical sweetish-oily odour.
Given its fatty acid composition, mango butter is most similar to shea butter and is considered its best substitute. However, the consistency of mango butter is slightly more solid and it contains less unsaponifiable matter.
Mango seeds contain up to 50% water and must therefore be quickly dried after harvesting to reduce the water content to approximately 10%. The harvesting period for mango fruit in the countries of southwest Asia, which are the leading producers of mango butter, coincides with the monsoon season. Such demanding climatic conditions make the processing of mango fruit very difficult. Wet seeds are suitable for the extensive development of microorganisms, especially Aspergillus niger. Fungus lipases degrade triglyceride molecules into free fatty acids. In unrefined mango butter produced from fresh seeds, the content of free fatty acids was shown to increase from 2 to 7% in 20 days, and to 46% in 120 days.
Mechanism of action and use
Mango butter is used as an emollient ingredient in a variety of cosmetic products, e.g. skin and hair cleansing cosmetics, skin and hair care cosmetics, lip care cosmetics and decorative cosmetics. It is also very popular in products for massage. Due to its high content of phytosterols, it may contribute to antioxidative activity and restore the impaired function of the lipid barrier. In vivo laboratory studies with an emulsion containing 25% mango butter have shown accelerated wound healing. Similar effects have been observed with the same emulsion used in volunteers. Scientific literature describes some very rare cases of contact dermatitis caused by the dermal use of mango butter.
Source: Modern Cosmetics - Dr. Damjan Janeš and Dr. Nina Kočevar Glavač
Lecithin is a natural mixture of polar and neutral lipids; the word lecithin is also used as the trivial name of a particular phospholipid: phosphatidylcholine. Main vegetable
sources of lecithin used in personal-care products are soybean and maize, egg yolk is practically the only animal source of lecithin used in cosmetics and toiletries. The percentage of polar lipids and their fatty acid pattern are characteristic of the lecithin source.
Bare lecithin, a secondary product of Soya oil extraction, typically contains 60 to 70% polar lipids (mainly phospholipids, namely phosphatidylcholine, and glycolipids) and a remaining 25 to 35% Soy oil. This raw lecithin is further fractionated, purified, and chemically modified to allow easier processing and formulation in toiletry products. Emollient, refattening, and moisturizing properties of lecithin are guided by its content in phospholipids.
Lecithin softens, nourishes, and refattens the skin; it provides a nongreasy, long-lasting skin feel and improves foam feel and quality (creaminess, slipperiness, richness).
Ready-to-use mixtures of phospholipids in surfactant solutions, free of residual Soya oil, are commercially available for an easy incorporation in liquids or bars; some of these compounds allow formulation of clear products.
Source: Handbook of Cosmetic Science and Technology - André O. Barel, Marc Paye, Howard I. Maibach
Lanolin is extracted from sheep wool grease; it is a complex mixture of esters of high molecular weight lanolin alcohols (aliphatic alcohols, sterols, and trimethyl sterols) and of lanolin acids; free lanolin alcohols, acids, and lanolin hydrocarbons are minors. Lanolin alcohols and lanolin oil are recommended as superfatting agents in soaps.
Ethoxylation of the hydroxyl groups of lanolin or of its derivatives leads to hydrophilic, water-soluble lanolin compounds, offering a broad range of useful emollients to the formulator. Some moderately to highly ethoxylated derivatives, recommended for their good emolliency and moisturization properties, are processable in liquid skin cleansers with limited impact on foam profile; as an example, the 75 mol ethoxylated lanolin does not depress foam and is recommended as skin conditioner in soaps, liquid body-cleansing products, and bubble baths. Medium ethoxylates lanolin alcohols have limited impact on foam performances of body cleansing liquids; lower ethoxylates can be formulated in bars.
Propoxylated lanolin alcohols are lipophilic emollients used in soap bars and in other cleansers based on synthetic surfactants. Alkoxylated lanolin derivatives are obtained by reaction with mixtures of propylene and ethylene oxides in various ratios; they are more soluble than ethoxylated lanolin. They serve as refattening and foam stabilizing agents. Esterification of lanolin fatty acid with isopropyl alcohol provides a range of esters of various molecular weights. Medium molecular weight esters are used as superfatting agents in soaps.
Source: Handbook of Cosmetic Science and Technology - André O. Barel, Marc Paye, Howard I. Maibach
Lavandula Angustifolia Water is an aqueous solution of the steam distillate obtained from the Lavender, Lavandula angustifolia, Labiatae. is distilled from the flower buds of Lavandula angustifolia. It has the fresh, clean scent of lavender has been popular for centuries. The plant is often used as a gentle tonic for the nervous system and is said to soothe headaches and other aches and pains. The soothing and antiseptic qualities make lavender useful in all skin care. This material from the condensate of the distillation of the essential oil contains water soluble constituents as well as a small amount the essential oil and has a strong Lavender scent. It may be used alone as a facial tonic/toner or in blends to soothe irritated or burned skin. No adverse effects are expected or have been reported from the topical use of this material..
Source: Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4) . Dweck Data.
Lactic acid is found in nature in milk, it is also found in the skin. The role of lactic acid is to improve the integrity of the acid mantle of the skin and it acts as part of the skin’s natural moisturising function. It not only acts as an astringent, but also helps to moderate the pH of the skin to keep it slightly the acidic (the ideal value). Lactic acid is used in skin softening preparations and has been used at higher levels for the treatment of thickened skin conditions (e.g. calluses, warts, etc). The SCCNFP adopted a position paper (SCCNFP/ 0370/ 00) (1) on the safety of AHA based on studies on short term phototoxicity (sensitivity of human skin to UV-induced damage: sunburn cells and pyrimidine dimers production) and skin irritation. The SCCNFP considered that there was a need for more information in order to provide a full scientific assessment of the safety of AHA. However, on the precautionary principle, the SCCNFP suggested that: lactic acid up to a maximum level of 2.5 % and a pH ≥ 5.0. [CAS: 50-21-5; EINECS: 200-018-0]. Function: Buffering/ humectant/ skin conditioning. The actual or estimated LD50 value: 3,543 mg/kg body weight. AICS status (NICNAS Australia): AICS Compliant. Oral LD50 value (rat): 3,543 mg/kg. Dermal LD50 value (rabbit): 2,000 mg/kg. Lactic Acid. CIR: Concentration or other limitation on use for safe with qualifications conclusion: </=10%, at final formulation pH>/=3.5, when formulated to avoid increasing sun sensitivity or when directions for use include the daily use of sun protection;</=30%, at final formulation pH>/=3.0, in products designed for brief, discontin-uous use followed by thorough rinsing from the skin, when applied by trained professionals, and when application is accompanied by directions for the daily use of sun protection.
Source: Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4) . Dweck Data.
Lactobacillus Ferment is the product obtained from the fermentation of Lactobacillus Lactobacillus fermentum is a Gram-positive species of bacterium in the genus Lactobacillus. It is associated with active dental caries lesions. It is also commonly found in fermenting animal and plant material. It has been found in sourdough. A few strains are considered probiotic or "friendly" bacteria in animals and at least one strain has been applied to treat urogenital infections in women. A patent was issued that claimed The present invention concerns methods and compositions for prophylactic or therapeutic treatment of skin disorders by administering therapeutically or prophylactically effective amounts of a probiotic and is also concerned with the treatment of symptoms of skin disorders. Lactobacillus is used for skin disorders such as fever blisters, canker sores, eczema (allergic dermatitis); and acne. It is also used for high cholesterol, lactose intolerance, Lyme disease, hives, and to boost the immune system. Women sometimes use lactobacillus suppositories to treat vaginal infections and urinary tract infections (UTIs). In light of the evidence there are few concerns for the topical application of this material.
Source: Dweck, Anthony. Handbook of Cosmetic Ingredients: - their use, safety and toxicology (Dweck Books 5)
A cosmetic leak test is a test that is conducted to ensure that the packaging of a cosmetic product is airtight and does not leak. The test is done by pressurizing the package and then looking for a drop in pressure over time.
The purpose of a cosmetic leak test is to ensure that the product is safe to use and that it will not spoil or become contaminated during its shelf life. The test also helps to prevent the product from drying out or evaporating.
There are a few different methods that can be used to conduct a cosmetic leak test. One common method is to use a differential pressure decay leak tester. This type of tester uses a pump to pressurize the package and then measures the rate at which the pressure drops over time. A leak will cause the pressure to drop more quickly.
The cosmetic leak test is an important part of the quality control of cosmetic products. It helps to ensure that the products are safe and effective for consumers to use.
Kojic acid, the chemical name 5-hydroxy-2-hydroxymethyl-4-pyrone, is used in cosmetic products as a skin whitening or depigmenting agent. Kojic acid is a chelating agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name of koji. It is a by-product in the fermentation process of malting rice, when producing sake (Japanese rice wine). It is used in food and cosmetics to help preserve against color changes. Kojic acid also has antibacterial and antifungal properties. Kojic acid markedly inactivated isolated tyrosinase by chelation. In cultured human melanocytes, tyrosinase activity per well was slightly reduced at the concentration range between 0.1 mM and 0.5 mM but was rapidly dose-dependently reduced at higher concentration. The inhibitory effect of kojic acid on tyrosinase activity in the cell culture system is smaller than that of arbutin at concentrations that do not affect cell viability, even though marked inactivation was observed in isolated tyrosinase. There are conflicting reports on the effectiveness in kojic acid. [Maeda and Fukuda]. Kojic acid may take two to three months to show efficacy and thus may seem rather slow to be effective. However, kojic acid does not have any side effects during the 10- to 20-month period during normal application on the skin. Kojic dipalmitate is mentioned in the Inventory of Cosmetic Ingredients, but derivative esters of Kojic acids are also used. The substance is listed as an emollient, whereas Kojic acid itself is listed as an antioxidant. Results of the range finding test indicated that the LD50 was in the range of 4000 to 16000 mg/kg bw. In the main experiment lethargy, piloerection, abnormal body carriage, ataxia and depressed respiration rate were observed shortly after dosing. These signs were accompanied by gasping amongst mice treated at 6400 mg/kg bw. Bodyweight increases of rats treated at 16000 mg/kg bw were slightly depressed during the first week. Recovery of survivors was apparently complete within four days of dosing. Autopsy revealed congestion of the lungs and pallor of the liver, kidneys and spleen in animals died after treatment. The LD50 and its 95% confidence limits were calculated to be 5100 (3900 – 6700) mg/kg bw. No erythema or oedema occurred in the test performed. Kojic acid was not considered to be an irritant to rabbit skin. In the preliminary test and in the first experiment, 3% Kojic acid aqueous solution caused no eye disturbances. In the second experiment mild transient hyperemia was observed in 2 of 4 animals. No other inflammatory changes or corneal disturbances were observed. Eye irritability was reported to be very weak. In the supplementary test no specific response was observed for up to 72 hours. Two out of 20 animals showed a positive reaction, indicating a sensitising potential of the substance. Kojic acid is sensitising in humans. Based on the information provided, margins of safety of respectively 35 (face and hands), 58 (hands) and 88 (face) have been calculated suggesting that the use of Kojic acid at a maximum concentration of 1.0% in skin care formulations poses a risk to the health of the consumer. In addition, other parts of the skin might be exposed to Kojic acid. Kojic acid has the potential to induce skin sensitisation. Relevant data on kinetics of Kojic acid after dermal application may be submitted to refine the MOS approach..
Source: Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4) . Dweck Data.
