MODULE 1. “TECHNOLOGY OF COSMETIC PRODUCTS“
Content modules: 1. Technology of cosmetic creams, liquids and makeup tools
SOFT COSMETIC PRODUCTS, CREAMS. SUSPENSIONS, GELS. DECORATIVE COSMETICS.
At the most basic level, gels are active ingredients suspended in a base of water and a thickening agent. Gels tend to be lighter and less moisturizing than creams or lotions, making them a suitable option for those with oily or acne-prone skin. Cooling, refreshing and more readily absorbed than many other topical formulations, gels are often used to deliver active ingredients in anti-cellulite products and in products designed for use around the delicate eye area. With the right ingredients and know-how, topical gels are relatively easy to make at home.
A gel is made from water and a thickening agent. Other ingredients are added for various purposes, depending on what the gel is used for. Gels are usually either clear or semi-opaque.
Thickeners are used very often in various cosmetic products. They enhance the consistency, volume and viscosity of cosmetic products, thereby providing more stability and better performance. While some thickeners have also emulsifying or gelling properties, the majority of thickeners have the ability to retain water on the skin and act therefore as moisturizers. Thickeners can be completely natural like waxes but also synthetic or semi-synthetic. They are derived from various sources and consist of very different molecular structures including polysaccharides, proteins, alcohols, silicones or waxes.
Advantages of gells:
– Not toxic;
– Does not irritate the skin;
– Softens and moisturizes the skin;
Disadvantages:
– Leaves the skin feeling stickiness;
– may dry out, so for increasing the viscosity, bioavailability and stability of gels the glycerol (10%), polyethylene glycol is added.
A gel is used in products where it is desirable to have little or no fats or oils and is best mixed using a water-based medium. If a small amount of fat is required in the gel, up to 5% vegetable oil can be added.
Gels are also able to carry an essential oil content of up to a maximum of 5%. Too much of either of these ingredients can result in an uneven distribution in the gel. The thicker the gel is, the more vegetable or essential oil it will be able to carry.
The thickening agents retain moisture, protect the skin and can also be astringent. They are not absorbed by the skin. Which thickening agents to use in the manufacture of gels is a question of taste, or rather of ‘feeling’ i.e. how the gel feels when applied to the skin and then how it feels when its moisture has evaporated. These thickening agents can either be wholly synthetic, such as a polymer or wholly natural, such as a polysaccharide.
Natural polysaccharides are extracted from plants or algae and are to be found in large quantities in:
Carrageen (extracted from the seaweed Carrageen)
Alginates (extracted from different algae)
Cellulose Gum (extracted from wood fibre)
Xanthan Gum (produced by Xanthomonas compestris bacteria through the fermentation of glucose – no bacteria are left in the finished product)
Gelling agents
PVP (Polyvinyl Pyrolidone) or VP (Vinyl Pyrolidone)
Acrylic acid copolymer
Acrylamide copolymer
Carboxymethyl hydroxyethylcellulose
Hydroxyethylcellulose
Polyvinyl laurate
Carbopol
Methylcellulose
Cellulose
Guar gum
Carrageenan
Pectin
Alginic acid,
Xanthan gum
Agar
Chitosan
Technology:
· Preparation of raw materials;
· Preparation of the gel (swelling a thickening agent with water);
· Adding active components;
· Packing, packaging, labeling the finished product.
Organic Guar Gum
Guar gum is a natural hydrocolloid that is obtained from the ground endosperm of the guar plant. This plant is basically an annual plant that grows in huge number in the arid regions of India as a food crop for the cattle. Mainly India and Pakistan enjoys the pleasure of being at the top of the list of guar growing countries. In India and Pakistan guar plants are generally found from July to December. Though formerly it was used mainly as food crop for animals, this crop is recently getting attraction widely throughout the world for guar gum, claims www.agcommoditiesinc.com.
Considering the craze and popularly of bars, sauces, juices and instant beverage throughout the world, a variety of gum system has become a necessity. Till now, the gum and additives used in instant food and beverages were mainly chemical and synthetic. But during recent years the craze and demand of organic food has largely increased the necessity of an organic emulsifier. Guar gum can very stably meet this necessity. Guar gum is basically a polysaccharide (a long chain of sugars) made of the sugars, galactose and mannose. Guar gum is white to off white powder, states www.agcommoditiesinc.com. Being odorless, guar gum can be easily and profusely used in food materials. Emulsifier is, actually, a kind of food additive used to keep oil dispersed and in suspension. An emulsifier is a substance that stabilizes an emulsion.
Examples of food emulsifiers are egg yolk (where the main emulsifying chemical is the phospholipid lecithin) and mustard. Emulsifier reacts chemically with both oil and water and thus stabilizes oil-in- water. For this property, emulsifier is largely used in making detergent, soap, and grease for the purpose of cleaning and even in pharmacy to prepare creams and lotions. These emulsifiers are not very much available naturally and organically. Therefore, the organic guar gum has achieved its popularity.
Organic guar gum is nowadays processed by companies and is available in the form of guar gum powder in different viscosities. This guar gum powder is widely used in order to serve as thickener in cosmetics. Cosmetics generally contain synthetics that can be harmful to skin. Guar gum powder can be used with safety in cosmetics, states www.agcommoditiesinc.com. This guar gum powder can again be added to sauces and salad dressings as an additive and to ice creams as an agent which prevents ice crystals from forming. Guar gum powder can also be used as fat substitute that adds the “mouth feel” to fat.
Consumers however, are not very much aware of the use of guar gum powder as stabilizer. This guar gum powder prevents the ‘weeping’ of the pastry by keeping the pastry crispy. Guar gum powder can really be a healthy substitute of synthetic stabilizers. Guar gum powder along with various stabilizers are used profusely nowadays for organic food and drink manufactures.
Guar gum powder coupled with xanthan gum or locust bean gum increases the viscosity (thickness) of the food materials while when used alone neither of these two gums (xanthan gum or locust bean gum) can produce such superiority. Thus guar gum powder gives a superb thickness to the food materials like jam, jelly or sauces even when used in a very little quantity, states www.agcommoditiesinc.com.
Organic guar gum is soluble fiber that is basically the single greatest dietary aid for preventing constipation and also curing irritable bowel syndrome. But the problem with soluble fiber is that it is not available in the foods such as bran or raw green vegetables that are thought to have fiver. On the contrary, soluble fiber is available in the foods commonly thought to have starches, such as cereal grains like barley, oatmeal. Oat bran, fruits like apple, banana, black berry and vegetables like broccoli, brussels, sprouts and carrots. Sources of soluble fiber are rice pasta, noodles, potatoes, carrots, beets, mushrooms etc.
But high consumption of these “starchy” foods may result into gaining calories for the consumer. Here organic guar gum can serve a lot. Organic guar gum can be used as a natural laxative while the other sources of soluble fiber cannot. Organic guar gum containing a high quantity of soluble fiber can be a very good aid to both irritable bowel syndrome and diarrhea. The soluble fiber present in organic guar gum dissolves in water though it is not digested. From www.agcommoditiesinc.com you can know that organic guar gum when consumed helps to absorb excess liquid in the colon adding a great deal of bulk as it passes intact through the gut.
This natural laxative (organic guar gum) has the capacity to prevent diarrhea. Besides being a natural laxative, organic guar gum adds no calorie to the body of consumer, as the soluble fiber content in organic guar gum is never digested in the body of consumer.
Moreover, being fully organic, this natural laxative contains no harmful chemicals as found in synthetic laxatives and thus has no side effect. So, this almost unknown substance on one hand improves thickening, suspension, freeze/ thaw stability, emulsion, stability and mouth feel properties to bakery, dairy products, meat, sauces, beverages, pharmaceuticals, ice creams, pet food etc. www.agcommoditiesinc.com states that it provides natural laxative to the consumer free with his favorite beverage. In conclusion, one thing worth mentioning is that, organic guar gum is not only an additive to food materials and laxative but also has wide application in textile printing, mining, water treatment, oil-drilling processing cigarette paper, explosives, agriculture and even soil erosion.
Hydroxyethylcellulose (HEC)
Hydroxyethylcellulose is a non-ionic, water soluble polymer used as a thickening agent for aqueous cosmetic and personal care formulations. It will produce crystal clear gel products and thicken the aqueous phase of cosmetic emulsions. It can be also be used to efficiently thicken shampoos, body washes and shower gels.
One of the problems normally associated with this and other water-soluble thickeners is the tendency of the particles to agglomerate or lump when first wetted with water. The high-purity cosmetic grade of Hydroxyethylcellulose we offer is an R-grade, designed to be added to water without lumping, and thus greatly facilitating solution preparation. It is also the most efficient grade of nonionic thickener available from the manufacturer.
Hydration of the R-grade particles has been inhibited. When the particles are added to water, they disperse without lumping, and following a predetermined delay, begin to dissolve. This process permits the preparation of clear, smooth, viscous solutions in a short period of time by simply adding the R-grade to water and stirring until the polymer is completely dissolved to prevent settling of the particles.
The inhibition period, from the initial wetting to the start of dissolution, is referred to as the hydration time. This hydration time can vary from 4-25 min. Hydration time is markedly affected by two factors: pH and temperature of the water. A higher temperature and a higher pH decrease the hydration time, but a too high temperature or pH can result in lumping. So, it is recommended that it be added to room temperature water with a neutral pH. Once hydrated, it can be heated and the pH can be adjusted as may be needed.
Typical Use Rate: 0.1 – 3%
Appearance: Off-white granular powder
Manufacturer: Hercules
Product: Natrosol 250 HHR CS
Solubility: Soluble in water
Viscosity: 3400-5000 cps (1% in water @ 25°C)
pH: 6.7 (1% in water)
Charge: Non-ionic
INCI: Hydroxyethylcellulose
** 50 lb bag is boxed and shipped separately from the balance of an order. Estimated shipping can be determined by placing the item in the cart on its own.
Hydroxyethyl Cellulose (HEC)
Property
Appearance: white or yellowish flowable liquid, odorless and smellless; Sieving efficiency(40 mesh):99% min. ; Softening temperature: 135-140°C; Apparent density: 0.35-0.61g/ml; Decomposition temperature: 205-210°C; slow combustion speed, balanced moisture content: 23°C, 50rh%: 6%£84rg%: 29%; Soluble in cold water and heat water, usually insoluble in most organic solvents. The viscosity become little when the PH ranges from 2 to 12, but the viscosity reduces beyond this range. The HEC treated on the surface is soluble only when the pH is from 8 to 10.
Important Properties As a nonionic surfactant, HEC has the functions such as thickening, suspension, emulsification, adhesion, film formation, dispersion, water retention, providing protection and the following properties:
1. Hydroxyethyl Cellulose (HEC) is soluble in heat water or cold water, don’t precipitate under high temperature or boiling, solubility and viscosity changes in a wide range;
2. Because of its nonionic property, it can coexist with other water-soluble polymer, surfactants and salts in wide range, is an excellent colloid thickener for high-concentration electrolyte solution;
3. Its water retention is twice of methyl cellulose, with excellent flow controllability;
4. Its dispersibility is the worst compared with methyl cellulose and hydroxypropyl cellulose, but the protection power for colloid is the strongest.
Uses
1. Used in Water Emulsion Coating:
2. HEC is used to protect colloid in acetic alkene emulsion polymerization, improve the stability of polymer in wide pH range, make pigment and additives uniformly disperse, stable and thicken in production of finished products. It is also used as dispersant in suspensive polymer such as styrene, acrylate, acrylonitrile, etc.
3. Used in Drilling Well:
4. As thickener used in all kinds of mud in drilling well, well cementation and fracturing operation, HEC can make mud excellent fluidity and stability, improve the carrying power of mud in drilling well and prevent water from going into oil layer from mud, make the output of oil layer stable.
3. Used in Building Materials:
Because of its strong water retention, Hydroxyethyl cellulose is an excellent thickener and adhesive for cement paste and mortar to improve fluidity and operation performance, lengthen vaporizing time of water, improve the beginning strength and avoid crack. It can effectively improve the water retention and adhesive strength when used in gypsum plastering, gypsum cementing and gypsum putty.
5. Used in Toothpaste:
6. Because of its strong salt resistance and acid resistance, Hydroxyethyl Cellulose (HEC) can make toothpaste stable; Because of its strong water retention and emulsification power, it make tooth not easy to dry;
5. Used in Water-soluble Ink, HEC can make ink dry fast and not penetrate.
Moreover, HEC is widely used in textile, printing, paper making, daily chemical, etc.
Dissolving and Preparing Method
1. Add clean water in vessel;
2. Add HEC under low-speed agitation, agitate to make all materials fully wet;
3. After HEC fully dissolve, add other needed ingredients;
4. Add alkali or ammonia to adjust pH to 8-10, form needed viscosity.
Specifications
Mole Degree of Substitution (M.S) 1.8-2.0
Moisture: 10% max.
Water-insoluble Matter: 0.5% max
pH: 6.0-8.5
Ash: 5% max
Viscosity(mpa.s), 20°C aqueous solution: 5-60000
HEC’s model is expressed as HS-6000, 6000 stands for nominal viscosity. If treated on the surface. its model is expressed as HS-6000S.
Methylcellulose
Methylcellulose, carboxymethylcellulose, and hydroxymethylcellulose are forms of the familiar polysacharide cellulose, treated to make it more soluble in water. Cellulose is a long chain made of the sugar glucose. The long chains mix with water to make a thick syrup or gel. Methylcellulose is used as a thickener in sauces and salad dressings, and as a thickener and stabilizer in ice cream, where it helps prevent ice crystals from forming during freezing or re-freezing after a thaw.
Methylcellulose is a Bulk Forming Fiber Laxative . Bulk laxatives absorb liquid in the intestines and swell to form a soft bulky stool. The bulky mass stimulates the intestinal muscles speeding stool transit time through the colon. Methylcellulose will not work as a bulking forming laxative without increased fluid intake.
Characteristics:
(1) Property: white powder, odorless, smellless and nontoxic.
(2) Water retention: Methylcellulose can absorb several times water than the weight itself to maintain high retention of water in stucco, plaster, coating, etc.
(3) Soluble in cold water to form transparent viscous liquid.
(4) Soluble in some organic solvent and the mixed solvent of water and organic compound because of the existence of hydrophobic group.
(5) Salt resistance: Methyl cellulose is a kind of nonionic and non-polyelectrolyte so as to be stable in metal salt and the aqueous solution of organic electrolyte. Gelatification and precipitation will occur if much electrolyte.
(6) Surface activity: its aqueous solution is of surface activity to act as colloid protective agent, emulsifier and dispersant.
(7) Heat gelatification: when heated to certain temperature, the aqueous solution will change into nontransparent one because of gelatification and precipitation. When gradually cooled, it will rechange into original state. The temperature of gelatification and precipitation is decided by the type of product, the concentration of solution and heated speed.
(8) Low ash: because of the property of heat gelatification, adopting heat water to wash during preparation to refine the product.Therefore, it is of low ash content.
(9) pH stability: the viscosity of aqueous solution is little affected by acid and alkali, its aqueous solution is stable in wide pH range from 3.0 to 11.0
(10) Shape retention: compared with other water-soluble polymer, its aqueous solution has special viscoelastic performance.
(11) Lubricating property: reduce friction coefficient to improve the lubricating property of ceramics and concrete products.
(12) Film-forming property: form solid, flexible and transparent film to show good resistance to oil and ester.
Dissolving method:
Heat the water to 80-90 and slowly add MC under continuous agitation, after reduction in temperature and cooling to form uniform aqueous solution. Or add one third to two third of needed water, heat them to 80-90 and slowly add MC under continuous agitation, after swelling, add residual cool water and cooling.
Usages: Methylcellulose is widely used as thickener, adhesive, water retention agent, film-forming agent, excipient and emulsifier in construction, building materials, dispersed coating, polymerization auxiliaries, cosmetic, medicine, food, leather, ink and paper making, etc.
CARBOPOL
Carbopol polymers are polymers of acrylic acid cross-linked with polyalkenyl ethers or divinyl glycol. They are produced from primary polymer particles of about 0.2 to 6.0 micron average diameter. The flocculated agglomerates cannot be broken into the ultimate particles when produced. Each particle can be viewed as a network structure of polymer chains interconnected via cross-linking1.
Carbomers were first prepared and patented in 19572. Since then, a number of extended release tablet formulations, which involve carbomer matrices, have been patented3.
Carbomers readily absorb water, get hydrated and swell. In addition to its hydrophilic nature, its cross-linked structure and its essentially insolubility in water makes Carbopol a potential candidate for use in controlled release drug delivery system.4,5
Chemical nature:
The USP-NF, European Pharmacopoeia, British Pharmacopoeia, United States
Adopted Names Council (USAN), and International Nomenclature for Cosmetic Ingredients
(INCI) have adopted the generic (i.e., non-proprietary) name “carbomer” for
various Carbopol homopolymer polymers. The Japanese Pharmacopoeia states, Carbopol
homopolymers as “carboxyvinyl polymer” and “carboxy polymethylene.” The Italian
Pharmacopoeia also identifies Carbopol 934P as “carboxy polymethylene” and the
Deutschen Artzneibuch calls Carbopol 980NF “polyacrylic acid.” Carbopol copolymers,
such as Carbopol 1342 NF and 1382, have also beeamed “carbomer” by the USP-NF,
but are considered “Acrylates/C10-C30 Alkyl Acrylates Cross polymer” by the
INCI.
Carbopol polymers are offered as fluffy, white, dry powders (100% effective).
The carboxyl groups provided by the acrylic acid backbone of the polymer are
responsible for many of the product benefits. Carbopol polymers have an average
equivalent weight of 76 per carboxyl group6. The general structure
can be illustrated with fig. No.1
Fig. No. 1 – General Structure of Carbopol Polymers.
Fig No. 2 – Schematic drawing of a molecular segment of a cross-linked
polyacrylic acid polymer
Carbopol polymers are manufactured by cross-linking process. Depending upon the degree of cross-linking and manufacturing conditions, various grades of Carbopol are available. Each grade is having its significance for its usefulness in pharmaceutical dosage forms7.
Carbopol 934 P is cross-linked with allyl sucrose and is polymerized in solvent
benzene.
Carbopol 71G, 971 P, 974 P are cross-linked with allyl penta erythritol and polymerized in ethyl acetate. Polycarbophil is cross-linked polymer in divinyl glycol and polymerized in solvent benzene. All the polymers fabricated in ethyl acetate are neutralized by 1-3% potassium hydroxide. Though Carbopol 971 P and Carbopol 974 P are manufactured by same process under similar conditions, the difference in them is that Carbopol 971 P has slightly lower level of cross-linking agent than Carbopol 974 P. Carbopol 71 G is the granular form Carbopol grade8.
Physical Properties 9:
The three dimensional nature of these polymers confers some unique characteristics, such as biological inertness, not found in similar linear polymers. The Carbopol resins are hydrophilic substances that are not soluble in water. Rather, these polymers swell when dispersed in water forming a colloidal, mucilage-like dispersion.
Carbopol polymers are bearing very good water sorption property. They swell in water up to 1000 times their original volume and 10 times their original diameter to form a gel when exposed to a pH environment above 4.0 to 6.0. Because the pKa of these polymers is 6.0 to 0.5, the carboxylate moiety on the polymer backbone ionize, resulting in repulsion between the native charges, which adds to the swelling of the polymer. The glass transition temperature of Carbopol polymers is 105°C (221°F) in powder form. However, glass transition temperature decreases significantly as the polymer comes into contact of water. The polymer chains start gyrating and radius of gyration becomes increasingly larger. Macroscopically, this phenomenon manifests itself as swelling.
Table No.1 Physical and Chemical Properties of Carbopol 10
Appearance |
Fluffy, white, mildly acidic polymer |
|
Bulk Density |
Approximately 208 kg/m3 (13 lbs. |
|
Specific gravity |
1.41 |
|
Moisture content |
2.0% maximum |
|
Equilibrium moisture content |
8-10% (at 50% relative humidity) |
|
PKa |
6.0 ± 0.5 |
|
pH of 1.0% water dispersion |
2.5 – 3.0 |
|
pH of 0.5% water dispersion |
2.7 – 3.5 |
|
Equivalent weight |
76 ± 4 |
|
Ash content |
0.009 ppm (average) ** |
|
Glass transition temperature |
100-105C (212-221F)
|
* Polymers produced in co solvent (a cyclohexane / ethyl acetate mixture) have a bulk density of 176 kg/m3 (11 lbs/ft3).
* * Polymers produced in ethyl acetate have an ash content (as potassium sulfate) of 1-3% on average.
Rheological properties :
While the relationships between structure and properties have been of interest both academically and in industry. Different grades of Carbopol polymers exhibit different rheological properties, a reflection of the particle size, molecular weight between crosslinks (Mc), distributions of the Mc, and the fraction of the total units, which occur as terminal, i.e. free chain ends11-18.
The molecular weights between adjacent crosslinks (Mc) are approximately inversely proportional to the crosslinker density. These may be calculated from the functionality of the crosslinking monomer, the relative ratio of acrylic acid to crosslinking monomer, and the efficiency of the crosslinking reaction, assuming negligible chain ends4. Alternatively, the molecular weight can be qualitatively compared to the rheological properties of a swollen gel and/or from the equilibrium-swelling ratio. In simple terms, low viscosity, low rigidity polymer, such as Carbopol 941 and Carbopol 971P, have a higher Mc. Conversely, they have lower crosslinker densities. The higher the crosslinker level, the lower the equilibrium swelling ratio. In the network theory of elasticity, the elastic modulus, G, is inversely proportional to the molecular weight between crosslinks (Mc). There have been attempts to extend the elasticity theory to swollen gels19,20. Based on this approach, Taylor calculated Mc for Carbopol 941 in the order of several million. This number is far too high as compared to the theoretical Mc calculated from the stoichiometry. Carnali and Naser estimated the Mc for Carbopol 941 to be 3,300 monomer units (or 3,300 x 72 = 237,600 gm/mole) derived from a combination of dilute solution viscosity and equilibrium swelling.9 The Mc reported for Carbopol 940 was 1,450 monomer units (or 1,450 x 72 = 104,400 gm/mole)4.
Table No. 2 – Viscosity range of different Carbopol Polymers21,22.
No. |
Polymer |
Viscosity* |
|
1 |
Carbopol 934 NF |
30500 – 39400 |
|
9 |
Carbopol 934 P NF |
29400 – 39400 |
|
12 |
Carbopol 71 G NF |
4000 – 11000 |
* Brookfield RVT Viscosity, cP 0.5 wt % mucilage at pH 7.5, 20 rpm
at 25oC
Applications of Carbopol polymers:
The readily water-swellable Carbopol polymers are used in a diverse range of pharmaceutical applications to provide:
· Controlled release in tablets1,23-26.
· Bioadhesion in buccal27,28, ophthalmic29,30, intestinal31, nasal32, vaginal33 and rectal34 applications.
· Thickening at very low concentrations to produce a wide range of viscosities and flow properties in topical, lotions, creams and gels, oral suspensions and transdermal gel reservoirs35,36.
· Permanent suspensions of insoluble ingredients in oral suspensions and topicals37.
· Emulsifying topical oil-in-water systems permanently, even at elevated
temperatures, with essentially no need for irritating surfactants.
Several properties of Carbopol make it potentially valuable as a pharmaceutical
excipient iumerous applications such as:
(1) Controlled release & solid dosage forms 22,23 38-44:
Carbopol is being used in the controlled release solid dosage formulations
since last four decades. The numbers of manufacturers commercializing controlled
release tablets using Carbomers are increasing considerably in recent period
of development. Tablet formulations using Carbopol polymers have demonstrated
zero-order and near zero-order release kinetics. These polymers are effective
at low concentrations (less than 10%). Still they show extremely rapid and efficient
swelling characteristics in both simulated gastric fluid (SGF) and simulated
intestinal fluid (SIF). The Carbopol polymers produce tablets of excellent hardness
and low friability. These polymers can be successfully formulated into a variety
of different tablet forms, including the traditional swallowable tablets, chewable
tablets, buccal tablets, sublingual tablets, effervescent tablets, and suppositories;
providing controlled-release properties as well as good binding characteristics.
Carbomers show larger dissolution times at lower concentrations than other excipients.
Because of these factors Carbopol polymers have greater extent in formulating
dosage forms. Because Carbopol polymers swell rapidly in water and absorb great
quantities, to avoid the use of flammable solvents, roller compaction is being
used as the method to prepare a new form of Carbopol polymer 71G NF. Carbopol
polymer 71G NF is a useful and versatile controlled-release additive for tablet
formulations in direct compression.
Drug Dissolution Mechanism from Carbopol Polymers
In the dry state, the drug is trapped in a glassy core. As the external surface of the tablet is hydrated, it also forms a gelatinous layer upon hydration, however, this gel layer is significantly different structurally from the traditional matrix tablet. The hydrogels are not entangled chains of polymer, but discrete microgels made up of many polymer particles, in which the drug is dispersed. The crosslink network enables the entrapment of drugs in the hydrogel domains. Since these hydrogels are not water soluble, they do not dissolve, and erosion in the manner of linear polymers does not occur. Rather, when the hydrogel is fully hydrated, osmotic pressure from within works to break up the structure, essentially by sloughing off discrete pieces of the hydrogel. It is postulated that as the concentration of the drug becomes high within the gel matrix and its thermodynamic activity or chemical potential increases, the gel layer around the tablet core actually acts almost like a rate-controlling membrane, resulting in linear release of the drug.Because of this structure, drug dissolution rates are affected by subtle differences in rates of hydration and swelling of the individual polymer hydrogels, which are dependent on the molecular structure of the polymers, including crosslink density, chain entanglement, and crystallinity of the polymer matrix. The magnitude and rate of swelling is also dependent on the pH of the dissolution medium. The channels which form between the polymer hydrogels are influenced by the concentration of the polymer, as well as the degree of swelling. Increasing the amount of polymer will decrease the size of the channels, as does an increase in swelling degree. All of these factors must be taken into account to describe the mechanism for release control in tablets formulated with Carbopol polymers.
Benefits in Solid Dosage Application –
· Efficient controlled release agents for matrix tablets.
· Improve bioavailability of certain drugs
· Efficient binders in dry as well as wet granulation processes.
· Only granular polymer (Carbopol 71G NF) available for direct compression formulation.
(2) Oral Suspension Applications 8,36,37,45,46:
For many years, Carbopol polymers have been widely used in oral suspensions
to thicken, modify flow properties, suspend insoluble ingredients and provide
bioadhesion. The significance of these polymers is that they eliminate the settling
problem even at low concentrations. As Carbopol polymers swell when hydrated
and neutralized, they form colloidal dispersion.
Carbopol 934 P has been used since mid 1960s. Carbopol 974 P has similar rheological
properties to Carbopol 934 P, as both are highly cross-linked polymers that
produce mucilage with very short flow rheology. Carbopol 971 P provides very
low viscosities and excellent yield values at low usage levels. Suspensions
formed with Carbopol 971 P will have longer rheology. Carbopol 71 G polymers
will give same viscosities and rheology as Carbopol 971 P, but it is easier
to handle and disperse due to its granular nature.
Benefits in Oral Suspension Applications:
· Long Term Stability of Suspensions over a wide pH range.
· Highly efficient at low use level.
· Taste masking of some bitter drugs.
· Build viscosity and yield value for “non-spill” pediatric formulations.
(3) Bioadhesive Applications 48-59:
Bioadhesion is a surface phenomena in which a material may be of natural or synthetic origin, adheres or stick to biological surface, usually mucus membrane. The concept of bioadhesion is emerging as a potential application in drug delivery due to its applicability for bioavailability enhancement, prolongation of residence time for drug in GIT and better contact between drug and absorbing surface.
Many hydrophilic polymers adhere to mucosal surfaces as they attract water from the mucus gel layer adherent to the epithelial surface. This is the simplest mechanism of adhesion and has been defined as “adhesion by hydration” Various kinds of adhesive force, e.g. hydrogen bonding between the adherent polymer and the substrate, i.e. mucus, are involved in mucoadhesion at the molecular level. Carbopol polymers have been demonstrated to create a tenacious bond with the mucus membrane resulting in strong bioadhesion.
Many commercial oral and topical products available today and under investigation have been formulated with Carbopol polymers, as they provide numerous benefits in bioadhesive formulations.
Benefits in Bioadhesive Applications –
· Improve bioavailability of certain drugs.
· Enhance patient compliance (fewer doses are needed per day)
· Lower concentrations of the active ingredients can be used.
· Provide excellent adhesion forces.
(4) Topical Applications60-66:
Carbomers are very well suited to aqueous formulations of the topical dosage
forms. Many commercial topical products available today have been formulated
with these polymers, as they provide the following numerous benefits to topical
formulations:
· Safe & Effective — Carbopol polymers have a long history of safe and effective use in topical gels, creams, lotions, and ointments. They are also supported by extensive toxicology studies.
· Non-Sensitizing — Carbopol polymers have been shown to have extremely low irritancy properties and are non-sensitizing with repeat usage.
· No Effect on the Biological Activity of the Drug — Carbopol polymers provide an excellent vehicle for drug delivery. Due to their extremely high molecular weight, they cannot penetrate the skin or affect the activity of the drug.
· Excellent Thickening, Suspending, & Emulsification Properties for Topical Formulations
Products with a wide range of viscosities and flow properties have been successfully formulated and commercialized. Carbopol polymers are used to permanently suspend the active ingredients in transdermal reservoirs as well as in topical gels and creams. Pemulen polymeric emulsifiers can be used to prepare stable emulsions, such as turpentine liniment, without the use of surfactants. Carbopol polymers and Pemulen polymeric emulsifiers are often the thickener and emulsifier of choice in topical lotions.
(5) Oral Care Applications 67-70:
Carbopol polymers impart several desirable characteristics to toothpaste formulations like Viscosity, Yield Value, Low thixotropy and Clarity.
Imparting viscosity at very low concentrations to thicken a system is a primary function of the polymers. Suspending abrasives and solid actives is accomplished through the build of yield value at low polymer concentrations. The combination of Carbopol polymers’ ability to build yield value with low thixotropy provides for a clean, non-stringing ribbon of toothpaste. From aesthetic and practical perspectives this means that Carbopol toothpaste formulations are pumpable, leave minimal solids residue on the tube rim, stand up well on the brush, and can be used in clear formulations.
Benefits in Oral care Applications –
· Efficient co-binders at low usage levels.
· Suspending agents for non-soluble actives or excipients.
· Thicken peroxide gel systems while maintaining product stability.
· Compatible with commonly used formulation ingredients.
Toxicological studies 71 :
The Carbopol, like other high molecular weight polymers, demonstrate a low
toxic and irritation potential based on their physical and chemical properties.
Accordingly, such cross-linked, high molecular weight acrylic acid polymers
have been found safe for use in a wide variety of cosmetics, detergents and
pharmaceuticals by appropriate regulatory and non-regulatory bodies concerned
with such products. Acute oral studies with rats, guinea pigs, mice and dogs
showed that Carbomers- 910, -934, -940 and –941 have low toxicities when ingested.
The inhalation LC50 of Carbomers 910 in albino rats was 1.71mg/l.
the dermal LD50 of rats exposed to Carbopol 910 was greater than
3.0 g/kg. No mortalities occurred in rabbits injected intravenously with 1%,
2% or 3% Carbopol 934 in aqueous solution at a dose of 5 ml/kg. Rabbits showed
minimal skin irritation when tested with 100% Carbopol 910 or –934, and zero
to moderate eye irritation when tested with Carbomers 910, -934, -940, -941
and/or their various salts at concentrations of 0.20-100%. When Carbopol 934
P was fed orally to dogs and rats, there was no significant effect on body weight,
food consumption, mortality, behavior, and blood chemistry. The CIR Expert Panel
called attention to the presence of benzene as an impurity in the Carbopol polymers
and recommended efforts to reduce it to the lowest possible level.
Conclusion
The large variety of applications as well as the steadily increasing number of research workers engaged in studies of Carbopol polymers due to their unique properties, have made significant contributions to many types of formulations and suggest that the potential of Carbopol as novel and versatile polymer will be even more significant in future.
Hydroxypropyl Methylcellulose (HPMC) CAS No. 9004-65-3
Hydroxypropyl Methylcellulose (HPMC) is multifunctional as a lubricant, foam enhancer and stabilizer, thickener, emulsion stabilizer and film former for hair and skin care products. HPMC is especially useful in surfactant systems for its foam enhancing properties, helping with the formation of bubble structure, leading to richer, longer lasting lather. HPMC has a high tolerance for both salt and alcohol.
Techniques for Dispersion
· The preferred method is to begin by heating approximately 1/3 of the total formulation water to 167°F (75°C) or higher. Add the HPMC to the vortex of agitated and heated water. Mix until fully dispersed. HMPC will not dissolve at this temperature. After complete dispersion, add the remaining water at room temperature or colder and continue mixing for 30 minutes after the total solution has cooled to 77°F. (25°C) or less. Proceed with the formulation.
· If heating is impossible, it is preferred to slurry the HPMC in a non-solvating media, such as glycerin or PEG, then add the slurry to the vortex of vigorously agitated water. Adding HPMC directly to cold water is not preferred, but if necessary, must be done very slowly under vigorous agitation. Expect longer mixing times for complete dissolution.
Typical Use Rate: 0.1 – 2%
Manufacturer: Hercules
Product: Benecel MP824
Appearance: Off-white granular powder
Solubility: Soluble in water
Nonionic
pH: 5.5 – 8.0 (2% solution)
INCI: Hydroxypropyl Methylcellulose
Natural Source Product
The History of Makeup
There’s a lot of talk about how today’s society is obsessed with appearances. There is this underlying belief that there was less pressure to change your appearance for beauty’s sake before modern society. When you actually look at the habits of people hundreds or thousands of years ago, you will see that appearance has always been important to society.
Around 10,000 BCE, the Ancient Egyptians were developing almost every kind of cosmetic that we would use today. They had creams for stretch marks and to fight aging. They used oils to moisturize their skin and they had an array of perfumes. To them, looking attractive was the best way to get close to the gods.
Around 4000 BCE, the women wore copper and ore, known as mesdemet, around their eyes to make their eyes stand out. They also put malachite, a mixture of copper minerals, on their cheeks, and Kohl became the main product for lining their eyes. A lot of their cosmetics had multiple purposes. Their eye makeup helped keep bugs at bay. Some cosmetics could be consumed to fight different ailments. The cosmetics weren’t just for women; men used them as well.
Around 3000 BCE, Greeks and Chinese began whitening their faces. The Chinese used rice powder and the Greeks used white lead. Greek women would apply berries on their cheeks as rouge. The Chinese would paint their nails using a variety of ingredients. Each color meant you were of a different social class. Around 1500 BCE, the Chinese began painting their teeth black or gold and shaved off their eyebrows.
Around 100 AD, Romans used butter and barley powder to get rid of pimples. They also used sheep fat and blood to paint their nails. Mud baths became popular and some Roman men died their hair blonde. The people of India began using Henna around 300 AD as a way to dye their hair as well as for religious decorating of the body.
In England in the Middle Ages, it was popular for women to dye their hair red or to wear egg whites on their face to whiten it. During the Renaissance, around the 1400s, only the Aristocracy used cosmetics. They began using arsenic instead of lead in some powders. Around 1500 AD, European women used a variety of products, some quite dangerous to their health, to lighten their skin. Blonde hair became more popular due to its angelic appearance.
Around 1800 AD, it is found that zinc oxide, which is commonly used in today’s cosmetics, is much safer than lead for use on the skin. Queen Victoria denounced makeup as vulgar. It lost some popularity and was only acceptable for use by actors.
In Edwardian society, around the 1900s, makeup regained its appeal. As hosts, women were expected to have a youthful appearance. They turned to buying cosmetics at beauty salons in secrecy to avoid anyone knowing that they needed the products to look young. Around the 1920s tanned skin gained popularity. By 1930, there were several products to tan your skin without the sun.
Today there is a wide variety of cosmetics for every need of which anyone could imagine. There are a variety of brands, with each having its own variances of colors and styles. There are different types of brushes for applying different types of makeup. Makeup is not only a way to enhance one’s beauty; it has become somewhat of an art. It is the foundation for the fashion world. Most people won’t leave home without having first applied several different cosmetics, whether it’s soap, lotion, or makeup.
The price of looking beautiful is something nearly every human being, going back to the earliest of societies, has paid. It’s in humaature to want to look and feel attractive. The next time you think today’s society is superficial, remind yourself of the products used by Ancient Egyptians and Renaissance women. At least our products today are relatively safe.
Makeup types
Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and gels, deodorants, hand sanitizer, baby products, bath oils, bubble baths, bath salts, butters and many other types of products. A subset of cosmetics is called “make-up,” which refers primarily to colored products intended to alter the user’s appearance. Many manufacturers distinguish between decorative cosmetics and care cosmetics.
Most cosmetics are distinguished by the area of the body intended for application.
Face Primer, Come in various formulas to suit individual skin concerns. Most are meant to reduce the appearance of pore size, prolong the wear of makeup, and allow for a smoother application of makeup. Applied before foundation.
Eye Primer, Used to prolong the wear of eyeshadows on the eye as well as intensify color payoff from shadows.
Lipgloss, is a sheer form of lipstick that is in a liquid form.
Lipstick, lip gloss, lip liner, lip plumper, lip balm, lip conditioner, lip primer, and lip boosters. Lip stains have a water or gel base and may contain alcohol to help the product stay on the lips. The idea behind lip stains is to temporarily saturate the lips with a dye, rather than covering them with a colored wax. Usually designed to be waterproof, the product may come with an applicator brush or be applied with a finger.
Concealer, makeup used to cover any imperfections of the skin. Concealer is often used for any extra coverage needed to cover blemishes, or any other marks. Concealer is often thicker and more solid than foundation, and provides longer lasting, and more detailed coverage. Some formulations are meant only for the eye or only for the face.
Foundation, used to smooth out the face and cover spots or uneven skin coloration. Usually a liquid, cream, or powder, as well as most recently, a light and fluffy mousse, which provides excellent coverage as well. Foundation primer can be applied before or after to get a smoother finish. Some primers come in powder or liquid form to be applied before foundation as a base, while other primers come as a spray to be applied after you are finished to help make-up last longer.
Face powder, used to set the foundation, giving a matte finish, and also to conceal small flaws or blemishes.
Rouge, blush or blusher, cheek coloring used to bring out the color in the cheeks and make the cheekbones appear more defined. This comes in powder, cream, and liquid forms.
Contour powder/creams, used to define the face. It can be used to give the illusion of a slimmer face or to even modify a person’s face shape as desired. Usually a few shades darker than ones own skin tone and matte in finish to create the illusion of depth. A darker toned foundation/concealer can be used instead to contour to create a more natural look.
Highlight, used to draw attention to the high points of the face as well as to add glow to the face. It comes in liquid, cream, and powder form. Often contains shimmer, but sometimes does not. A lighter toned foundation/concealer can be used instead to highlight create a more natural look.
Bronzer, used to give skin a bit of color by adding a golden or bronze glow. Can come in either matte, semi matte/satin, or shimmer finishes.
Mascara is used to darken, lengthen, and thicken the eyelashes. It is available iatural colors such as brown and black, but also comes in bolder colors such as blue, pink, or purple. There are many different formulas, including waterproof for those prone to allergies or sudden tears. Often used after an eyelash curler and mascara primer. There are now also many mascaras with certain components to help lashes to grow longer and thicker. There are specific minerals and proteins that are combined with the mascara that can benefit, as well as beautify.
Eyelash glue, Used to adhere false lashes to the eyes. Can come in either clear or colored formulas.
Eyebrow pencils, creams, waxes, gels and powders are used to color and define the brows.
Nail polish, used to color the fingernails and toenails.
Setting Spray, used to keep applied makeup intact for long periods of time. An alternative to setting spray is setting powder which may be either pigmented or translucent.
Cosmetics can be also described by the physical composition of the product. Cosmetics can be liquid or cream emulsions; powders, both pressed and loose; dispersions; and anhydrous creams or sticks.
Eyeliner used to enhance and elongate the size of the eye.
Makeup remover is the product used to remove the makeup products applied on the skin. It is used for cleaning the skin for other procedures, like applying any type of lotion at evening before the person go to sleep.
FACE POWDERS
Face powders are used to cover minor imperfections and reduce the shine that appears on the skin due to sebum or perspiration. They are required to give a matt, smooth finish to the skin and remain this way for as long as possible. This means that all the ingredients used must adhere well to the skin. In recent times the fashion has changed from a ‘painted clown’ look to one that appears to be as natural as if the skin had no product applied, but without the imperfections. Modern products are also required to be ‘long-lasting’, preferably all day, and consequently avoid repeated application; they should not rub off onto clothing (either that of the wearer or of anybody else). There are two main forms of face powder. Loose face powder comes in a sealed tambourine inside a decorative plastic container. It is either applied directly from this by a puff or large brush, or is transferred to a special compact in which it can be carried in a handbag and is applied with a sponge or small puff that also fits in the compact. To prevent leakage a nylon mesh covers the surface of the powder. In its second form the powder is compacted or compressed and a binding agent is used in its manufacture. Whatever the format, the face powder must have the following characteristics:
1. The powder should have the required covering power to mask minor visible skin imperfections.
2. It should adhere to the skin and must not be completely dissipated in a short time, so avoiding frequent re-powdering.
3. The finish given to the skin must complement the skin colour, imparting a velvet or peach-like character.
4. Shine on or around the nose must be completely eliminated. The powder must be absorbent without changing its appearance on the skin.
5. There must be sufficient slip to enable the powder to be applied to the skin with a suitable applicator, such as a puff or brush, without dragging or producing a blotchy effect.
6. The constituents of the powder should be such that a clown-like effect is impossible. The preference should be towards transparency.
The popularity of loose face powders waned with the advent of compact (compressed) powders and developments in foundation and liquid make-up. However, it is still considered by some that loose powder gives a more ‘professional’ finish and there is a resurgence in popularity from time to time. New uses for ‘face powders’ have been established, such as the correction of heightened colour where there is too much red colouration or too much yellow in the case of sallow complexions. The borderline between what constitutes a face powder and a foundation has become very blurred with the development of dual-function products.
(a) Colour of the finished face powder
The colour of the finished face powder is a matter of taste and fashion. It is normally necessary to produce a range of shades that will blend with and enhance the natural complexion. Today’s natural skin colour tends more towards a cream colour with only a few complexions tending towards blue for which the ‘clear pink’ shades are suitable. The range of colours offered should be based on shades suitable for the main complexion types such as blond and fair-skinned or brunette and dark-skinned.
The colour effect when the powder is applied to the skin is dependent upon the opacity of the white and tinted pigments used, their particle size, the degree of dispersion, the thickness of the applied film and the skin’s colour. The performance of coloured products is always assessed when it is applied to the skin. The inner forearm is an area often used by formulators. The reason for this assessment of colour on the skin is that the colour of a thin film of pigment may be different from the effect given by the powder when viewed in bulk. The thin film colour effect is known as the ‘undertone’ and the bulk effect as the ‘mass’ tone. Colour dispersion within the base formula, and colour grinding to bring out maximum shade development, are both important stages of face powder preparation, both in the laboratory at the development stage and in final manufacture. If these stages are not followed rigorously, batch-to-batch colour variation will arise from poor pulverization of pigments resulting in under-development of shade intensities.
6.4.1 General manufacturing process
The initial stages of the manufacturing process are the same for both loose and pressed powders, but the latter requires the addition of a binder, either prior to or with the perfume.
(a) Colour extension
A key stage in the processing of pigmented powder products is the homogeneous dispersion of the pigments in the white base. Dispersion is dependent upon the efficiency of the mixing equipment and the physical characteristics of the materials included in the powder mixture. Homogeneous dispersion of the pigments is achieved by adequate extension of the pigments by passing the pigment and talc through a hammer mill. This breaks up the pigment agglomerates, which then stabilize by becoming coated onto the talc particles. There are now several types of equipment available to replace, wholly or partially, the hammer mill. One, a vertical vortex mixer, employs a fluidized vortex motion, reducing particle size by particle-particle collision. Another, a high-speed mixer, is known as a plough-shear device. This equipment uses a high-speed chopper in addition to mixing paddles rotating on an axial shaft. The chopper is mainly responsible for the powder extension.
(b) Base powder preparation
The white base ingredients are first mixed in a stainless-steel ribbon-type blender. The initial mixing time could be from 20 minutes to 3 hours, depending on the mixer type, capacity and the batch size. Next, the extended colours are added to the blended white base. This mixture is blended until a homogeneous mixture is achieved. With a loose face powder the perfume is the final addition. Spraying the perfume into the blender assists even distribution. For pressed powders the binder system will also be sprayed in at this stage. Finally the colour is checked against the standard and any corrections made. If micabased materials are used in the formulation, great care is taken to ensure the fragile platelets are not damaged by processing. Colour correction is generally done by removing a small quantity of the bulk and mixing in the appropriate extended colours. This is then added back to the main vessel and the bulk is re-mixed and checked again for colour. The effect of the pearlescent pigments on the final colour of the powder is taken into account during the colour correction work.
The checked bulk is then emptied into double polyethylene bags for storage or, to achieve a fine powder, pulverized and screened prior to bagging. The powder is ready for the next stage in the process: filling in the case of a loose face powder, or pressing in the case of a compact powder.
(c) Compacting process
Three different procedures can be employed to obtain a compact powder: wet moulding, damp compressing and dry compressing. The latter is the most widely used method. For the dry compacting process there is a choice of machinery available, each working on a different principal: pneumatics used in the Air-Mite press; hydraulics used by Alite, the ram type with the punch coming down onto the powder as seen in the Kemwall press; and the Ve-Tra-Co press where the punch remains fixed and the godets are pushed from beneath. Providing the bulk powder has been carefully manufactured and is allowed to stand to enable the release of any trapped air, pre-pressing should not be necessary. Pre-pressing occurs when a lower pressure is slowly applied to the powder to assist the removal of trapped air, prior to the compacting pressure being applied. The amount of pressure required to produce an acceptable cake is influenced by several factors, such as the base formulation, the type and quantity of binder, the moisture content of the powder and the godet size. Trial pressings need to be carried out to determine the correct machinery settings.
Lipstick
Cosmetics can be traced back to ancient civilizations. In particular, the use of lip color was prevalent among the Sumerians, Egyptians, Syrians, Babylonians, Persians, and Greeks. Later, Elizabeth I and the ladies of her court colored their lips with red mercuric sulfide. For years, rouge was used to color both the lips and the cheeks, depending on the fashion of the times.
In Western society during the latter half of the nineteenth century, it was generally believed only promiscuous women wore lipstick—or makeup at all. It was not until the twentieth century that lipstick, and cosmetics in general, gained true societal acceptance.
Improvements in the manufacture of applicators and metal tubes reduced the cost of the cosmetic. This combined with newfound acceptance by the general population caused widespread use and popularity to increase. By 1915 push up tubes were available, and the first claims of “indelibility” were made.
Lipsticks are made to appeal to the current fashion trend and come in a wide range of colors. Lipstick is made of dyes and pigments in a fragranced oil-wax base. Retail prices for lipsticks are relatively low, with quality products priced at less than $4.00. More expensive products are available, with prices ranging up to nearly $50.00 for exclusive products. Lip balms, by contrast, generally retail for less than $1.00.
The tubes that hold lipstick range from inexpensive plastic dispensers for lip balms to ornate metal for lipsticks. Sizes are not uniform, but generally lipstick is sold in a tube 3 inches (7.6 centimeters) in length and about .50 inch (1.3 centimeters) in diameter. (Lip balms are generally slightly smaller in both length and diameter.) The tube has two parts, a cover and a base. The base is made up of two components, the twisting or sliding of which will push the lipstick up for application. Since the manufacture of the tube involves completely different technologies, we will focus here on the manufacture of lipstick only.
Raw Materials
The primary ingredients found in lipstick are wax, oil, alcohol, and pigment. The wax used usually involves some combination of three types—beeswax, candelilla wax, or the more expensive camauba. Wax enables the mixture to be formed into the easily recognized shape of the cosmetic. Oils such as mineral, caster, lanolin, or vegetable are added to the wax. Fragrance and pigment are also added, as are preservatives and antioxidants, which prevent lipstick from becoming rancid. And while every lipstick contains these components, a wide variety of other ingredients can also be included to make the substance smoother or glossy or to moisten the lips.
Just as there is no standard to the lipstick size and container shape, there are no standard types of, or proportions for, ingredients used. Beyond the base ingredients (wax, oil, and antioxidants) supplemental material amounts vary greatly. The ingredients themselves range from complex organic compounds to entirely natural ingredients, the proportions of which determine the characteristics of the lipstick. Selecting lipsticks is, as with all cosmetics, an individual choice, so manufacturers have responded by making a wide variety of lipsticks available to the consumer.
To make lipstick, the various raw ingredients are first melted separately, and then the oils and solvents are ground together with the desired color pigments.
In general, wax and oil make up about 60 percent of the lipstick (by weight), with alcohol and pigment accounting for another 25 percent (by weight). Fragrance is always added to lipstick, but accounts for one percent or less of the mixture. In addition to using lipstick to color the lips, there are also lip liners and pencils. The manufacturing methods described here will just focus on lipstick and lip balms.
The Manufacturing Process
The manufacturing process is easiest to understand if it is viewed as three separate steps: melting and mixing the lipstick; pouring the mixture into the tube; and packaging the product for sale. Since the lipstick mass can be mixed and stored for later use, mixing does not have to happen at the same time as pouring. Once the lipstick is in the tube, packaging for retail sale is highly variable, depending on how the product is to be marketed.
Melting and mixing
1 First, the raw ingredients for the lipstick are melted and mixed—separately because of the different types of ingredients used. One mixture contains the solvents, a second contains the oils, and a third contains the fats and waxy materials. These are heated in separate stainless steel or ceramic containers.
2 The solvent solution and liquid oils are then mixed with the color pigments. The mixture passes through a roller mill, grinding the pigment to avoid a “grainy” feel to the lipstick. This process introduces air into the oil and pigment mixture, so mechanical working of the mixture is required. The mixture is stirred for several hours; at this point some producers use vacuum equipment to withdraw the air.
After the pigment mass is prepared, it is mixed with the hot wax. The mixture is agitated to free it of any air bubbles. Next, the mixture is poured into tubing molds, cooled, and separated from the molds. After final touch-up and visual inspection, the lipstick is ready for packaging.
3 After the pigment mass is ground and mixed, it is added to the hot wax mass until a uniform color and consistency is obtained. The fluid lipstick can then be strained and molded, or it may be poured into pans and stored for future molding.
4 If the fluid lipstick is to be used immediately, the melt is maintained at temperature, with agitation, so that trapped air escapes. If the lipstick mass is stored, before it is used it must be reheated, checked for color consistency, and adjusted to specifications, then maintained at the melt temperature (with agitation) until it can be poured.
As expected, lipsticks are always prepared in batches because of the different color pigments that can be used. The size of the batch, and the number of tubes of lipstick produced at one time, will depend on the popularity of the particular shade being produced. This will determine the manufacturing technique (automated or manual) that is used. Lipstick may be produced in highly automated processes, at rates of up to 2,400 tubes an hour, or in essentially manual operations, at rates around 150 tubes per hour. The steps in the process basically differ only in the volume produced.
Molding
5 Once the lipstick mass is mixed and free of air, it is ready to be poured into the tube. A variety of machine setups are used, depending on the equipment that the manufacturer has, but high volume batches are generally run through a melter that agitates the lipstick mass and maintains it as a liquid. For smaller, manually run batches, the mass is maintained at the desired mix temperature, with agitation, in a melter controlled by an operator.
6 The melted mass is dispensed into a mold, which consists of the bottom portion of the metal or plastic tube and a shaping portion that fits snugly with the tube. Lipstick is poured “up-side down” so that the bottom of the tube is at the top of the mold. Any excess is scraped from the mold.
7 The lipstick is cooled (automated molds are kept cold; manually produced molds are transferred to a refrigeration unit) and separated from the mold, and the bottom of the tube is sealed. The lipstick then passes through a flaming cabinet (or is flamed by hand) to seal pinholes and improve the finish. The lipstick is visually inspected for air holes, mold separation lines, or blemishes, and is reworked if necessary.
8 For obvious reasons, rework of the lipstick must be limited, demonstrating the importance of the early steps in removing air from the lipstick mass. Lipstick is reworked by hand with a spatula. This can be done in-line, or the tube can be removed from the manufacturing process and reworked.
Labeling and packaging
9 After the lipstick is retracted and the tube is capped, the lipstick is ready for labeling and packaging. Labels identify the batch and are applied as part of the automated operation. While there is a great deal of emphasis on quality and appearance of the finished lipstick product, less emphasis is placed on the appearance of lip balms. Lip balms are always produced in an automated process (except for experimental or test batches). The heated liquid is poured into the tube in the retracted position; the tube is then capped by machine—a far less laborious process.
10 The final step in the manufacturing process is the packaging of the lipstick tube. There are a variety of packaging options available, ranging from bulk packs to individual packs, and including packaging as a component in a makeup kit or special promotional offering. Lip balms are packaged in bulk, generally with minimum protection to prevent shipping damage. Packaging for lipsticks varies, depending on what will happen at the point of sale in the retail outlet. Packaging may or may not be highly automated, and the package used depends on the end use of the product rather than on the manufacturing process.
Byproducts
There is little or no waste in the manufacture of lipstick. Product is reused whenever possible, and since the ingredients are expensive they are seldom thrown out, unless no other alternative presents itself. In the normal manufacturing process there are no byproducts, and waste portions of lipstick will be thrown out with the disposal of cleaning materials.
Quality Control
Quality control procedures are strict, since the product must meet Food and Drug Administration (FDA) standards. Lipstick is the only cosmetic ingested, and because of this strict controls on ingredients, as well as the manufacturing processes, are imposed. Lipstick is mixed and processed in a controlled environment so it will be free of contamination. Incoming material is tested to ensure that it meets required specifications. Samples of every batch produced are saved and stored at room temperature for the life of the product (and often beyond that) to maintain a control on the batch.
As noted above, appearance of lipstick as a final product is very important. For this reason everyone involved in the manufacture becomes an inspector, and non-standard product is either reworked or scrapped. Final inspection of every tube is performed by the consumer, and if not satisfactory, will be rejected at the retail level. Since the retailer and manufacturer are often times not the same, quality problems at the consumer level have a major impact on the manufacturer.
Color control of lipstick is critical, and one only has to see the range of colors available from a manufacturer to be aware of this. The dispersion of the pigment is checked stringently when a new batch is manufactured, and the color must be carefully controlled when the lipstick mass is reheated. The color of the lipstick mass will bleed over time, and each time a batch is reheated, the color may be altered. Colorimetric equipment is used to provide some numerical way to control the shades of lipstick. This equipment gives a numerical reading of the shade, when mixed, so it can identically match previous batches. Matching of reheated batches is done visually, so careful time and environment controls are placed on lipstick mass when it is not immediately used.
There are two special tests for lipstick: the Heat Test and the Rupture Test. In the Heat Test, the lipstick is placed in the extended position in a holder and left in a constant temperature oven of over 130 degrees Fahrenheit (54 degrees Celsius) for 24 hours. There should be no drooping or distortion of the lipstick. In the Rupture Test, the lipstick is placed in two holders, in the extended position. Weight is added to the holder on the lipstick portion at 30-second intervals until the lipstick ruptures. The pressure required to rupture the lipstick is then checked against the manufacturer’s standards. Since there are no industry standards for these tests, each manufacturer sets its own parameters.
The Future
Lipstick is the least expensive and most popular cosmetic in the world today. In 1986 lipstick sales in the United States were more than $720,000,000. There are no accurate figures for current sales of lip balm, since the market is expanding. Manufacturers continue to introduce new types and shades of lipstick, and there is a tremendous variety of product available at moderate cost. As long as cosmetics remain in fashion (and there is no indication that they will not) the market for lipstick will continue to be strong, adding markets in other countries as well as diversifying currently identified markets.
Mascara
Mascara is a cosmetic applied to the eyelashes to make the lashes thicker, longer, and darker. It is one of the most ancient cosmetics known, having been used in Egypt possibly as early as 4000 B.C. Egyptians used a substance called kohl to darken their lashes, eyebrows, and eyelids. Egyptian kohl was probably made of galena or lead sulfite, malachite, and charcoal or soot. The Babylonians and ancient Greeks also used black eye cosmetics, as did the later Romans. Cosmetics of all sorts fell out of use in Europe after the fall of Rome, though eye cosmetics continued to be important in the Arab world. The use of cosmetics was revived in Europe during the Renaissance.
Early mascara from the modern era usually took the form of a pressed cake. It was applied to the lashes with a wetted brush. The ingredients typically were 50% soap and 50% black pigment. The pigment was sifted and combined with soap chips, run through a mill several times, and then pressed into cakes. A variation on this was cream mascara, a lotion-like substance that was packaged in a tube. To apply it, the user would squeeze a small amount of mascara out of the tube onto a small brush. This was a messy process that was much improved with the invention in the 1960s of the mascara applicator. This patented device was a grooved application rod that picked up a consistent amount of mascara when pulled from the bottle. The grooved rod was soon replaced with a brush. This new ease of application may have contributed to the increased popularity of mascara in the late 1960s.
Raw Materials
There are many different formulas for mascara. All contain pigments. In the United States, federal regulations prohibit the use of any pigments derived from coal or tar in eye cosmetics, so mascaras use natural colors and inorganic pigments. Carbon black is the black pigment in most mascara recipes, and iron oxides provide brown colors. Other colors such as ultramarine blue are used in some formulas. One common type of mascara consists of an emulsion of oils, waxes, and water. In formulas for this type of mascara, beeswax is often used, as is carnauba wax and paraffin. Oils may be mineral oil, lanolin, linseed oil, castor oil, oil of turpentine, eucalyptus oil, and even sesame oil. Some formulas contain alcohol. Stearic acid is a common ingredient of lotion-based formulas, as are stiffeners such as ceresin and gums such as gum tragacanth and methyl cellulose. Some mascaras include fine rayon fibers, which make the product more viscous.
The Manufacturing Process
There are two main types of mascara currently manufactured. One type is called anhydrous, meaning it contains no water. The second type is made with a lotion base, and it is manufactured by the emulsion method.
Anhydrous method
1 In this method, ingredients are mixed in tanks or kettles, which make a small batch of 10-30 gal (38-114 1). The ingredients are first carefully measured and weighed. Then a worker empties them into the mixing tank. Heat is applied to melt the waxes, and the mixture is agitated, usually by means of a propeller blade. The agitation continues until the mixture reaches a semi-solid state.
Mascara can be made in two different ways. In the anhydrous method, all the ingredients are mixed, heated, and agitated. With the emulsion method, water and thickeners are combined, while the waxes and emulsifiers are mixed and heated separately. Pigments are added before both mixtures are combined in a high-speed agitator called a homogenizer. The result of either method is a semi-solid substance that is ready to be packaged.
Emulsion method
2 In this method, water and thickeners are combined to make a lotion or cream base. Waxes and emulsifiers are heated and melted separately, and pigments are added. Then the waxes and lotion base are combined in a very high speed mixer or homogenizer. Unlike the tank or kettle above, the homogenizer is enclosed and mixes the ingredients at very high speed without incorporating any air or causing evaporation. The oils and waxes are broken down into very small beads by the rapid action of the homogenizer and held in suspension in the water. The homogenizer may hold as little as 5 gal (19 1), or as much as 100 gal (380 1). The high-speed mixing action continues until the mixture reaches room temperature.
The following steps are common to both types of mascara.
Filling
3 After the mascara solution has cooled or reached the proper state, workers transfer it to a tote bin. Next, they roll the tote bin to the filling area and empty the solution into a hopper on a filling machine. The filling machine pumps a measured amount (typically about 0.175 oz [5 g]) of the solution into glass or plastic mascara bottles. The bottles are usually capped by hand. Samples are removed for inspection, and the rest are readied for distribution.
Quality Control
Checks for quality and purity are taken at various stages in the manufacture of mascara. The chemicals are checked in the tank before the mixing begins to make sure the correct ingredients and proper amounts are in place. After the batch is mixed, it is rechecked. After the batch is bottled, representative samples from the beginning, middle, and end of the batch are taken out. These are examined for chemical composition. At this point they are also tested for microbiological impurities.
The Future
Some mascaras on the market today boast all-natural ingredients, and their recipes vary little from products that might have been made at home 100 years ago. One development that may affect mascara manufacturing in the future, however, is the development of new pigments. Researchers in the plastics industry have developed bold, vivid pigments that have recently been introduced to lipsticks. Plastic-derived pigments may be of interest to mascara manufacturers as well.
