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Skin Creams
Skin Creams In cosmetics, creams signify a solid or semisolid emulsion. If an emulsion has a viscosity which allows for pouring, due to gravity, then it is not a cream. However, creams and lotions will be dealt with together as skin creams. Ingredients and types of creams are numerous that no comprehensive books can contain all details. In addition, new products and ingredients are being introduced on daily basis. Classification of Skin Creams Traditionally, creams are classified according to their function, some cream types are listed below: 1. Cleansing creams: they are oily in nature due to medium to high oil content 2. Cold creams: can be either o/w or w/o emulsions which are difficult to rub-in. Both cleansing and cold creams contain surfactants to improve penetration and suspension properties. 3. Moisturizing creams: These are characterized by low oil content and ease of spreading and rub-in. Usually contain emollients and moisturizing ingredients. 4. Vanishing creams: These are composed of a low slip-point oil phase and are neutral or slightly acidic and may contain emollients and special moisturizing agents. 5. Protective creams: Usually of low to medium oil content and are easily spreadable. They may have a slightly alkaline or acidic properties and contain protective oils like silicones and lanolin. 6. All-purpose cream: Medium oil content which can be an o/w or a w/o emulsion but very often slightly oily. They are easily spreadable. The cosmetic chemist should observe the following in any cream formulation: 1. Volume ratio of oil to water. 2. The nature of the continuous phase. 3. The pH of the emulsion. 4. The type of the emollients used. 5. The slip-point of the oil phase. Cleansing Creams To ensure a healthy and good looking skin, one should remove: 1. Grime 2. Sebum and other secretions 3. Dead cells 4. Crusts 5. Applied makeup Water is an excellent and cheap cleansing agent but unfortunately very weak on oils. Therefore, soaps and detergents are added to water to improve its cleansing properties. However, the use of such cleanser is convenient in bath rooms or similar places. In addition, too much oil can be removed from the skin surface leaving it dry and rough and when alkaline soaps are used outermost cells may separate from their neighbors. Properties of a good cleansing cream
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Skin Creams
1. 2. 3. 4. 5. 6.
Water and oil based with medium to high oil content Unable to completely degrease the skin Leave a thin film of emollient oil Easily spreadable Should not rub-in Should not irritate the skin
Traditionally, cleansing creams were composed of beeswax and olive oil. Both have characteristic odor which should be masked. Therefore, in the twentieth century, mineral oil substituted olive oil. In addition, borax was found to have a positive effect on the characteristics of creams as borax reacts with the free fatty acids from wax forms soaps in situ. Although beeswax is still used in many preparations, it has two disadvantages: 1. It has a characteristic odor which should be masked 2. Its price and quality are variable throughout the year and location Borax is usually mixed with the molten wax where the sodium salts of the free fatty acids will be formed at the oil/water interface. The amount of borax added is about 5-6% of the mass of the wax. This means that only part of the free fatth acids will be converted to soaps. However, this ratio was found to result in better cream formulations. Examples of cleansing cream formulations Ingredient Beeswax Mineral oil Borax (Na2B4O7)
1 5 45 0.2
2 16 50 0.8
3 12 0.5
Monocrystalline wax Spermaceti* Sesame oil Paraffin wax Water Perfume, preservative
7 10 32.8 Qs
33.2 Qs
12.5 40 35 Qs
*Spermaceti is the semiliquid, waxy substance found in the head of the Sperm Whale, this is extracted from whale oil by crystallisation at 6 °C
Bentones (A clay formed by the decomposition of volcanic ash, having the ability to absorb large quantities of water and to expand to several times its normal volume) are used as alternatives to waxes as thickeners for oil phase. Preparation of Creams 1. The oil phase is heated to 75 o C until melting occurs 2. Borax is dissolved in water and heated to 75 o C 3. The aqueous phase is slowly added to the oil phase with continued stirring until the temperature reaches 45 o C where the perfume is added. www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
Improving the Efficiency of Cleansing Creams Nonionic surfactants can be used to increase the efficiency of the beeswax/borax emulsions and usually results in more stable preparations. The most widely used nonionic surfactant is the sorbitan fatty acid esters.
Sorbitan monostearate Examples of formulations that use nonionic surfactants: Ingredient Beeswax Mineral oil Lanolin Borax Hydrogenated vegetable oil Antioxidant Sorbitan sesquioleate Sorbitan stearate (an emulsifier, a thickener and a stabilizer of essential oils in lotion products) *Polysorbate 60 (Polyoxyethylene (20) Sorbitan Monostearate) Water Perfume Preservative
1 10 50 3.1 0.7 1 -
2 10 20 3.0 0.7 25 0.5 5.0
35.2 Qs Qs
2.0 33.8 Qs Qs
*A viscous, oily, water-soluble emulsifier enabling water & oil to mix. Used to stabilize cream preparations and act as a modifier and stabilizer of shampoos.
Cellulose derivatives are sometimes used in order to thicken oil in water emulsions as in the following formulation: Ingredient Beeswax Mineral oil Paraffin wax Cetyl alcohol PEG 15 cocamine Borax Cellulose derivative (thickener) water
% 8.0 49 7.0 1.0 1.0 0.4 0.2 33.4
Beeswax derivatives have also been used as o/w emulsions. The following two formulations are commercially www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
available: Ingredients Mineral oil Beeswax PEG-8 sorbitan beeswax PEG-20 sorbitan beeswax Polysorbate 40 Perfume, preservatives water
1 50 12 3 Qs 35
2 50 7 8 2 Qs 33
Cold Creams Lighter creams of the o/w type are also available. The following 5 formulations are examples of such creams (formulations 1 & 2 are good wash creams): Ingredients Mineral oil Stearic acid Triethanolamine Glyceryl stearate Carboxymethyl cellulose Water Glycerin Sodium alginate Cety lalcohol Spermaceti *Squalene Perfume preservative
1 30 10 2 0.5 57 Qs Qs
2 29 13.5 1.8 52 2 1.8 Qs Qs
3 18 15 55 5 2 5 -
4 10 3 1.8 85 0.5 Qs Qs
5 4 1 66 1 28 Qs Qs
Qs Qs
*Squalene (an oil free moisturizer) is a natural organic compound originally obtained for commercial purposes primarily from shark liver oil, though there are botanic sources as well, including rice bran, wheat germ, and olives. All higher organisms produce squalene, including humans. It is a hydrocarbon and a triterpene. The structure of squalene is shown below:
Acidity of the Skin Since the discovery of the acidic nature of the skin, creams were made buffered slightly acidic. Also, washability was observed to improve when the sodium salt of cetylsulfate was used. The cetyl derivative was found to be www.monzir-pal.net/Industrial/Skin Creams.htm
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better than lauryl due to its higher emulsification ability, less foam, as well as lower irritation.
An example of such a formulation is listed below: Ingredient Sorbitan sesquioleate Ozokerite wax* Petrolatum** Mineral oil Lanolin Water Lemon juice Perfume, preservative
% 8 30 4 10 12 30 6 Qs
*is a waxy mineral that is a mixture of hydrocarbons and occurs in association with petroleum or coal. Its melting point from 58 to 100 °C. It is soluble in ether, petroleum, benzene, turpentine, chloroform, carbon disulfide, &c. Galician ozokerite varies in color from light yellow to dark brown, and frequently appears green owing to dichroism. It usually melts at 62 °C. Chemically, ozokerite consists of a mixture of various hydrocarbons, containing 85-7% by weight of carbon and 14-3% of hydrogen. ** A smooth, semisolid blend of mineral oil with waxes crystallized from the residual type of petroleum lubricating oil; the wax molecules contain 30-70 carbon atoms and are straight chains with a few branches or naphthalene rings; used as a lubricant, as a carrier in polishes and cosmetics, and as a rust preventive. Good washability creams also find good markets. Example formulations are listed below: Ingredient Mineral oil Ozokerite wax Cetyl alcohol Sodium cetyl sulfate Water Beeswax Paraffin wax Petrolatum Perfume, preservative
1 40 3 2 1 54 Qs
2 52 3 3 23 5.6 5 8.4 Qs
Some other formulations may contain vitamins especially A, B, D, and F. Vitamin C is usually added as an antioxidant. Moisturizing and Vanishing Creams Moisturizing creams are most widely used in order to attain a soft and smooth skin. Vanishing creams are characterized by their ease of spreading and rapid disappearance. www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
Types of Dry Skin Normally, three types of dry skin can be identified: 1. Dryness is due to prolonged exposure to low humidity which modify the normal hydration gradient of the skin. 2. Dryness can be caused through physical or chemical factors leading to continual degreasing. 3. Dryness of skin due to aging, which is primarily due to UV exposure. Strategies to restoring water to dry skin: 1. Use of humectants 2. Occlusive approaches (like gloves, lanolin, mineral or vegetable oil) 3. Use of artificial skin lipid mixtures Most recently, quaternium substances of cellulose and gluconic acid (quaternary ammonium complexes) have been found to act as skin barrier materials that not only behave as moisturizers but also as skin conditioners. Examples of formulations using quaternium substances are listed below: Ingredient Isopropyl linoleate* Glyceryl stearate* Diisopropyladipate* Myristyl myristate* PEG-40 stearate* Cetyl alcohol Quaternium 22 Hydroxyethyl cellulose (2%) Propylene glycol Water Perfume, preservative
% 2 3 2 1 1 1.5 2 25 3 59 Qs
* alkyl esters are used as emollients A formulation of a simple vanishing cream is shown below: Ingredient Stearic acid KOH Glycerin Water Perfume, preservative
% 15 0.7 8 76 Qs
Hand Creams www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
Hands are usually subjected to severe environmental conditions like soaps, and hot detergents, among many others. These materials solubilize lipids and damage cell walls. Hands will become dry and flaky which is referred to as dishpan hands. Hand creams are supposed to remedy this problem and mosturize the skin as well. In this respects, lotions are preferred over solid creams. Hand Dermatitis The hands of some people are sensitive to normal daily activities and easily become dry, cracked, and scaly. Water, soap, detergents, and cleansers are the most common reasons in triggering this problem, which occurs in housewives, nurses, cooks, beauticians, waiters and others whose hands are repeatedly wetted. The rash caused by these exposures is a mild to severe irritation, not an allergy. Blistering rashes may occur on the hands. They may look like dishpan hands, and are irritated and worsened by water and cleanser exposure. The treatment of these ‘hand eczemas' of whatever cause is the same. Prevention of Further Irritation 1. Decrease exposure to water and cleansers as much as possible. This might mean asking another household member to do some of these chores, or being temporarily transferred to another sort of job at work. Frequency of wetting and drying is more important than the duration of wetting, so washing one large load of dishes a day is better than doing several small ones during the day. If you can use tongs and long-handled brushes when practical, this decreases water exposure. Unfortunately, rubber or plastic household gloves are not of great benefit in protecting you from common household exposures because it is the wetting which is most damaging, and gloves trap sweat and make the hand completely wet after a few minutes of wearing. Avoiding wetting is much more effective than trying to protect against wetting. 2. Lubricating the skin is important to replace natural skin oils leached out by wetting. You should stop using all commercial hand lotions and moisturizing creams and use only the products your doctor recommends, because many of the commercial products contain fragrances and other chemicals which are irritants. Plain greases, such as mineral oil or Vaseline, are the safest. These should be rubbed in thinly very often: after every water exposure, and whenever the skin feels dry. This may require applications as often as 10 times a day, especially at the beginning, but overlubrication is impossible, and underlubrication is harmful. 3. Treatment of the inflamed skin itself is by cortisone creams. Potent ones are usually necessary because penetration through thick skin is poor. The cortisone cream or ointment is applied thinly two or three times a day, especially after water exposure. If the cream alone does not suppress redness and itching, then a much greater effect can be obtained by covering the cream with a disposable plastic glove. This ‘occlusion' greatly increases penetration of the medication, and softens and humidifies dry skin. After wearing the gloves overnight, for a few hours, or as long as possible, the hands should be rinsed and a cortisone cream or lubricant applied to prevent drying. If only the palms of the hand have a rash, then the glove fingers can be cut off to make wearing the glove more comfortable. After the rash has improved, or is under control, a mild cortisone cream is used instead of the potent one. Prolonged use of potent cortisone creams, especially under plastic gloves, may cause thinning of the skin. Lubricants alone will suffice if the rash has resolved, and cortisone creams can be used again if a relapse occurs. www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
If the hand inflammation does not respond to external therapy, then your doctor may recommend cortisone pills or shots. These usually improve the rash but may have internal side effects, and the rash may reappear when they are stopped, so they are used with caution for only short periods. Examples of such lotions are listed below: Example 1: Ingredient Glyceryl stearate Cetyl alcohol Dimethicone Lanolin oil Squalene Sodium lauryl sulfate Water Perfume, preservative
% 2.7 1.5 1.5 2 3 0.3 T0 100 Qs
Example 2: Ingredient
% Stearic acid 7 Lanolin 0.5 Sorbitan oleate 0.5 Sorbitol* 10 Water To 100 Perfume, preservative Qs * A white, sweetish material, C6H8(OH)6, found in various berries and fruits or prepared synthetically and used as a flavoring agent, a sugar substitute and a moisturizer in cosmetics and other products. Example 3: Ingredient CTAB Cetyl alcohol glycerin Lanolin oil Isopropyl myristate Water Perfume, preservative
% 1.5 2.5 8 2 3 T0 100 Qs
All Purpose Creams As mentioned earlier, these creams are characterized by medium oil content and can be formulated to be easily spreadable. Examples are shown below: Example 1: Ingredient % www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
Trioleate phosphate Petrolatum Glyceryl stearate Isopropyl palmitate Cetyl alcohol Stearyl heptanoate Stearyl octanoate Sorbitol Water Perfume, preservative
3 18 5 4 2 0.5 0.5 5 T0 100 Qs
Example 2 and 3: Ingredients Stearic acid Beeswax Lanolin Mineral oil Polysorbate 85 Sorbitol trioleate PEG-40 stearate Sorbitol Water Perfume, preservative
1 15 2 4 23 1 1 12 T0 100 Qs
2 15 2 2 34 5 10 T0 100 Qs
See also the following information from the literature on facial creams: FORMULATIONS BASICS: FACIAL CREAM Before starting... Facial care creams formulations include many kinds of formulations, depending on the nature of the skin or on the desired effects. Either protection against pollution and oxidation is needed or anti-wrinkle activity. Actives may also be added in order to correct an oily/ greasy skin, a dry or a sensitive skin.. Many formulations are basically Oil in Water emulsions or Water in Oil emulsions. The typical skin care emulsion is now more likely to be o/w than w/o. Technology has advanced to the point where w/o stable emulsions can be prepared at room temperature. Required qualities : Neutral or pleasant odor and color Easy to spread, pleasant feeling during application Easy penetration Non-oily/ non-greasy after application Non comedogenic Well tolerance/ non-allergenic www.monzir-pal.net/Industrial/Skin Creams.htm
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Skin Creams
Bring hydration Typical Ingredients Must Use Emulsifiers Emollients Thickener Deionized Water
Usual Method
2-6% 10-35 % 0.1-1% Q.S.
Usual
Aqueous phase: Thickener is dispersed in cold or warm water at 75-80°C (depending on the recommandations of the producer) under intensive stirring, until a homogeneous gel is formed. This first phase is combined with the oily phase (Lipophilic components : emulsifiers + emollients + consistency factors) that has also been melted and heated to the same temperature. Mix under intensive stirring until emulsion is formed. Then mix gently while emulsion is being cooled. Sensitive components like actives, special additives and preservatives are added after the mixture has been cooled (40-30°C) to keep their properties intact.
Preservatives 0.2-1 % Humectants 1-8 % Consistency 1-6% Tips factors Antioxidants 0.01-0.05% How to vary the consistency of your cream? UV filters 0.01-0.5% - Changing the % of the oily phase allows variations in the final viscosity of your preparation. For Oil in Water emulsion the Optional greater the oily phase the higher the viscosity. Inversely for Water in Oil or Water in Silicone emulsion : the greater the Chelating 0-0.02 % aqueous phase the higher the viscosity. Agents - Vary the % of thickeners (gelling agents or consistency agents Fragrance 0.1-1 % like waxes). However some stabilizers can prevent settling Active agents 0.1-2% without increasing the viscosity. Colouring Q.S. agents Aesthetic 0.1-5% enhancers Sample Recipe : "Vanishing cream" Ingredients Composition Phase A Glyceryl stearate
Stearic acid Ceteareth-12* Octyldodecanol Paraffinum liquidum
Method % Phase A and phase B have to be mixed Function (w/w) and heated separately to 80°C. Add slowly B into A under intensive stirring until the emulsion is formed. Then add more quickly Emulsifier/ the rest of the phase and keep stirring consistency 4.00 during a few minutes. Continue stirring agent gently until the temperature is at 40°C. Then Emulsifier/ Add phase C. Keep stirring the mixture consistency 16.0 slowly while it is being cooled. agent Emulsifier 3.00 *Ceteareth-n (where n is a number) refer to Emollient 3.00 polyoxyethylene ethers of a mixture of high Emollient 3.00 molecular mass saturated fatty alcohols
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Skin Creams
Phase B Triethanolamine pH buffer 0.50 Deionized Water 69.3 Phase C Phenoxyethanol, methyl-, ethyl-, propyl-, butyl-, Preservative 0.7 isopropyl paraben Fragrance 0.5
Dry skin formulation
Enhance aesthetic
(mainly cetyl alcohol and stearyl alcohol). The number n indicates the average number of etyhlene oxide residues in the polyoxyethylene chain. These compounds are non-ionic surfactants, fequently used as emulsifiers in cosmetics
Ingredients choice criteria: - Slow down the TEWL (Transepidermal water loss) by using occlusive emollients in the oily phase (squalane, beeswax, triglycerides, essential fatty acids, silicones..) - Reenforce or reconstitute the NMF (Natural moisturizing factor) with adequate additives (sodium lactate, sodium PCA) - Bring humectancy with hygroscopic components (urea, allantoin, polyols, hyaluronic acid..) As indicated above, aesthetic enhancers may be added: eg- pearlescent pigments, texturing agents, soft-feeling agents like silicone elastomers.
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