Transcript Skin care 1. Definition 2. Function 3. Basic skin care 4

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Skin care
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Definition
Function
Basic skin care
formulations
Definition :
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Largest organ of the body
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It covers 1.2 2 meter square and wt
about 4 kg
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Completely exposed to the outside
elements.
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Skin function :
Barrier function.
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Temperature regulations.
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Protection against harmful effect of UV
light through our pigment cells
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Sensory organ.
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production ... vitamin D.
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Immune function.
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Identification of skin type :
Normal skin : has an equal balance between
water and oil, medium sized pores, well hydrated,
smooth and firm to touch.
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Dry skin : dull, rough to touch, flaky, small
pores, lack of hydration.
TEWL: Transepidermal water loss, which kept
to a minimum in by NMF, inters cellular lipids,
keratinized cells. Alteration in TEWL can cause dry
skin and it is affected by factors like central heating,
wind , cold, contact with water, nutrition,
surfactants.
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3.
Oily skin : results from hyper production
of sebum, skin looks as orange peel; large
hair follicle, slight shine prone to black
head, and acne.
Sebum production are controlled and
affected by the following factors cause:
Genetic, hormonal, stress, diet .. Etc.
Factors may cause temporarily
sebaceous gland activity :
Menstrual cycle, contraceptive,
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Sebum composed of :
triglcerides, free fatty acids, wax
esters, cholesterol.
Max secretion at puberty at
about 20 years then decreased by
28% after each decade.
4. Combination skin :
Mixture of dry and oily skin.
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Basic skin care :
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Skin care forms the largest sector of cosmetics market
Condition of face , neck and hands indicate the general
condition of skin
Skin is the body sacrificial organ, the first to show sign
of stress
Skin reflect general mental and physical well being.
People spend a lot of money on skin care products.
Skin care should not be for treatment only, it should be
priority and daily routine.
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Consumers needs can be roughly
divided into Two areas (table 1):
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Protection from
Repair of
UVR
IRR
Wind
Central heating
Chemicals
Cold
Pollution
Insects
Dry skin
Sunburns
Acne
Wrinkles
Puffy eyes
Cellulite
Skin cancer
Pigmentation
Age spots
Scares
basic skin care is daily routine of skin care :
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This include five steps :
1. Precleanse : warm water on cotton ball to soften and
loosen oil and dirt.
2. Cleans.
3. Toners and astringents : to prepare skin to absorb
ingredient from moisturizer.
4. Moisturizer.
5. Sun screen.
Remembers ABCs of sun safety .. :
Avoid peak sunlight hours 10 a.m. to 3 p.m.
Wear protective clothing (e.g. hat).
Use sunscreen with SPF of at least 15.
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Cleansing products
Soaps/synthetic detergent-based products
 Soaps (effective, inexpensive,alkaline)
 Synthetic detergents includes:
Shower gel
Liquid hand soap
Foam bath
Facial cleanser
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Facial cleaners normally contain : Formula
1. Mixture of SAA (anionic , anionic/
amphoteric).
2. Thickening agents : NaCl,and other
viscosity modifiers: cellulose derivative, PEG
esters, poly acrylic acid (carbapol®).
3. Refatting agent : usually natural oil.
4. Humactants : glycerol, propylenglycol.
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5. Silicon derivatives : increase in popularity
because it impart smoothness without stickiness (e.g.
quaternary poly dimethyl silicon, dimethicone
copolyol).
6. Hydrolysed protein.
7. Natural oil and extracts.
8. Proteolytic enzymes : keratolytic agents.
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Cleansing products
Cleansers for oily skin
 Facial mask and exfoliating lotion rather
than facial scrubs.
 Formula:
Synthetic detergent system
Astringent
Oil controlling agents and soothing
agents (oily controlling cleansers)
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Cleansing products
Emulsion cleansers
 Cleansing cream
 Rinse-off emulsion(foaming cleanser)
 Cleansing fluid emulsion (milk/lotion)
 sebum absorbing material
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- Some skin care ingredients
1. Plant extracts commonly used in skin-care
products
Their beneficial effects might be due to its moisturizing, antioxidant,
anti-inflammatory and photo-protective properties of natural
ingredients.
2. Special additive / nutrients:
- Vitamins: Vitamin C has been used extensively in cosmetic
formulations for their skin lightening activity, free radical scavenger
and collagen synthesis anti-aging properties. Ascorbic acid was
found to cause epithelium thickening, with cells of larger volume in
the granular and spiny layers. Vitamin E protect skin from ultraviolet
light, reducing the appearance of fine lines and wrinkles, helps
delay ageing and has skin moisturizing properties due to its
antioxidant activity.
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Special additive / nutrients:
- Proteins.
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Essential fatty acids: Evening primrose,
flaxseed or borage oils were found to be
beneficial for atopic skin conditions due to their
gama lenoleic acid content.
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Alpha- hydroxy acids
- AHAs are a group of organic carboxylic compounds. AHAs most
commonly used in cosmetic applications are typically derived from food
products including glycolic acid (from sugar cane), lactic acid (from sour
milk), malic acid (from apples), citric acid (from citrus fruits) and tartaric
acid (from grape wine).
-.Glycolic acid, having the smallest molecular size, is the AHA with greatest
bioavailability and penetrates the skin most easily; this largely accounts
for the popularity of this product in cosmetic applications.
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Alpha- hydroxy acids
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Epidermal effect
AHAs have a profound effect on keratinization; which is
clinically detectable by the formation of a new stratum
corneum. It appears that AHAs modulate this formation
through diminished cellular cohesion between
corneocytes at the lowest levels of the stratum corneum.
- Dermal effects
AHAs with greater bioavailability appear to have deeper
dermal effects. Glycolic acid, lactic acid and citric acid, on
topical application to photodamaged skin, have been
shown to produce increased amounts of
mucopolysaccharides and collagen and increased skin
thickness without detectable inflammation, as monitored
by skin biopsies.
TONERS
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The active component is astringent.
Material with astringent properties can be
classified as
a. Short chain alcohol e.g. ethanol.
b. Organic acid with low molecular wt e.g. lactic
acid.
c. Metal salt of organic or inorganic acid e.g. Al
sulfate.
d. Vegetable extracts containing tannins e.g. Witch
hazel.
TYPES OF TONERS
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Astringent lotions ( very oily & acne
prone skin )
 high Ethanol % ( Astringent ,
Antiseptic , Smooth sensation )
 Antimicrobial ( Benzalkonium Cl )
 Keratolytic ( salicylic acid )
 Toners
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& Fresheners
low% of Ethanol , Menthol
Skin Barrier Function
 Moisturizing Agents
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Humectants, emulsifiers and commercially available
moisturizers have been found to influence the barrier function in
normal skin. In damaged skin, topically applied substances can
both accelerate and retard normalization of the barrier function
to water. Furthermore, skin susceptibility to irritants is influenced
by certain moisturizers, which clearly indicates that ingredients
are not as inert to the skin as previously considered. This opens
up new possibilities to treat more efficiently various skin
abnormalities and different body areas, and to understand
various requirements among consumers.
Before going through moisturizers and their types and
applications, we will briefly discuss the structure of the skin and
types of human skin.
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Structure of the skin:
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A vertical section of the skin reveals three distinct layers,
namely the outermost epidermis, the dermis and finally the
hypodermis or subcutaneous layer (Fig.1).
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a) Epidermis:
The epidermis is a cellular structure, made up of many
layers of cells. The special structure of the epidermis is
classified as stratified squamous epithelium and is typical of
vertebrate animals.
It is responsible for producing the main barrier known as the
horny layer or stratum corneum, which forms the
outermost part of the epidermis. The horny layer is made up
of water-resistant dead cells, called corneocytes, which are
cemented together with a complex lipid material.
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Fig.1: Structure of the skin
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Fig.1: Structure of the skin
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Epidermis
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The epidermis varies in thickness from 75 to 150
micrometers (µm) in most areas to 6 mm on the palms of the
hands and the soles of the feet.
In terms of cells the epidermis consists of about 35 cell layers
of which 15-20 layers make up the horny layer.
The lower living layers of the epidermis can also be
subdivided as follows:
the germinative or basal layer;
the stratum spinosum or prickle cell layer;
the stratum granulosum or granular layer, which is
characterized by the presence of distinctive keratohyalin
granules.
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Epidermis
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The function of the epidermis is to produce and
maintain an efficient barrier called the stratum
corneum (horny layer).
Skin is continuously losing moisture to the
atmosphere by diffusion of water vapour through
the stratum corneum and the sweat glands. The
keratinized cells, NMF and intercellular lipid keep
this transepidermal water loss (TEWL) to an
acceptable minimum.
Epidermis renews itself once every 2 months.
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Moisturizing factor (NMF)
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The NMF acts as a water reservoir in the horny
layer which keeps the latter pliable and feeling
soft.
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The composition of the NMF is :
Components
Free amino acids
Lactate
2-Pyrrolidone carboxylic acid
Urea
Mineral Salts
Sugar, organic acids, peptides
Urocanic acids
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%
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4
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The dermis
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The dermis functions as a supporting frame to
the epidermis, supplying it with nutrients via the
blood capillaries. It also supports the sensory
nervous system, secretary glands and hair
follicles.
Unlike the epidermis, which is a cellular structure,
the underlying dermis consists of connective
tissue. Other examples of connective tissue in
the body include bone, cartilage and loose
areolar tissue.
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The dermis - collagen
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The dermis consists of connective
tissue, which consists of a fairly dense
network of protein fibers (such as
collagen and elastin, collagen forms
the major constituent of the fibrous
protein which gives the skin its tensile
strength) embedded in a hydrophilic
viscoelastic gel called the ground
substance.
The dermis – ground
substance
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Ground substance.The dermal ground
substance consists of salt, water and
glycosaminoglycans. The latter form
complexes with protein molecules known as
proteoglycans. The best-known examples of
'glycosaminoglycans' are hyaluronic acid
and chondroitin sulfate. Hyaluronic acid is
known to play a vital role in the hydration of
tissues since it carries with it a large volume
of water.
The hypodermis
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Below the epidermis is a layer of fatty or
adipose tissue called the hypodermis. The
cells in this layer synthesize and store fat as
an energy reserve. This is to help insulate
the body from low external temperatures
and to act as a buffer against trauma. On a
more familiar note, the hypodermis provides
the body with its contours, whether they are
attractive curves or unwelcome bulges.
Skin permeability
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In normal intact skin it has been established that the
keratinized corneocytes and the largely non-polar lipid
intercellular cement of the horny layer are the major
factors involved in the maintenance of an efficient
barrier.
The function is lost if the stratum corneum is removed
by tape-stripping techniques but is re-established
again after a few days when the stratum corneum
grows back.
In addition, dietary deficiency of essential fatty acids
such as linoleic acid results in skin with poor barrier
properties. The vast number of products and
chemicals that come into contact with the human skin
make it of vital importance that the horny layer is well
looked after.
Skin permeability
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Many raw materials which are commonly found in cosmetic
and toiletry products permeate into and through the stratum
corneum; some can also act as penetration enhancers for
other specific materials. Examples of penetrants include
water, glycerol, ethanol, phenol, urea, aluminum salts and
essential oils.
Common penetration enhancers include water, organic
solvents such as propylene glycol, surfactants and dimethyl
sulfoxide (DMSO). Occlusive dressings are often used to
increase the hydration of the stratum corneum. This is used
to promote the penetration of topically applied steroids.
Permeation tends to occur through the intercellular matrix,
but hair follicles, sebaceous glands and the sweat ducts
have been shown to provide a faster alternative route for
transport of highly polar molecules.
Skin permeability
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Damage to the skin may be caused by:
mechanical stress, chemicals, light and
micro-organisms (bacteria, yeasts, moulds
and viruses).
To the cosmetics manufacturer, chemicals
and light-induced damage are the most
important considerations.
Appropriate safety tests ensure that the
potential for a product or its component raw
materials to cause adverse reactions is
reduced to a minimum.
Skin permeability
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Adverse reactions include skin irritation and sensitization
which results in varying degrees of inflammation of the skin.
Inflammation of the skin is known as dermatitis, of which
there are many types.
Inflammation involves all the changes which take place in an
injured living tissue, provided that the injury does not
immediately kill the cells or destroy the tissue structure. The
visual signs of this activity, known as the triple response,
are:
- erythema ; redness
- oedema ; swelling
- flare ; more extensive reddening and swelling.
Each stage of the triple response can be measured
objectively, but these changes are accompanied by
subjective manifestations (burning, itching, and stinging)
which must also be taken into consideration.
Types of skin:
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Skin is often classified into four types according to the activity
of the oil producing sebaceous glands. This classification is
commonly used for facial skin because the skin type can vary
in the individual depending on age, body site, season and
state of health.
1. Dry skin.
2. Oily skin.
3. Normal skin is not particularly oily or dry. It is smooth
and firm to touch and the skin pores are barely noticeable.
4. Combination: this type of skin has a tendency to be
greasy in the central T-zone of the forehead, nose, central
cheeks and chin. The skin on the other areas is normal or
dry.
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Dry skin
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It has been established that water keeps the
horny layer supple and ensures neutralization of
acids and alkalis. A water content of 10-20% in
the stratum corneum is said to be required to
keep it soft and pliable.
An alteration of the barrier (by repeated
exposure to surfactants for instance) can cause
an increase in TEWL to the extent that water is
lost faster than it can be replaced from the
underlying tissues. This results in the horny layer
drying out, precipitating dry skin conditions.
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Dry skin
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Dry skin feels taut, rough and itchy. Closer
observation reveals the presence of very
fine wrinkles and, at a more advanced
stage, large scales.
The surface of severe dry skin is cracked
and is reddened (erythema) as a result of
the dilated peripheral blood capillaries in the
dermis. Environmental factors, sunlight and
ageing, plus numerous skin diseases and
dietary deficiencies, all produce dry skin.
Oily skin
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Oily skin results from, the excessive activity of
sebaceous glands which produce the lipid secretions
known as sebum.
There are several factors which can cause and/or
contribute to oily or greasy skin; genetic inheritance,
hormonal changes, diet, stress and external agents
(chemicals, ultraviolet light). Changes in hormone
levels which occur during puberty, the menstrual cycle,
use of oral contraceptives and pregnancy tend to
influence the activity of the sebaceous glands which
can result in a flare-up of oily skin.
Basic components of
moisturizing products
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A good moisturizing formulation is non-irritant, easy to
spread over the skin, easy to rub in without ‘soaping up’,
able to leave the skin feeling soft rather than sticky, and
pleasantly perfumed. If the product is to be unperfumed
there should be no fatty base odor. The basic components
of a moisturizing product include moisturizer, emulsifier
system, water, preservative and antioxidants if necessary.
Moisturizing preparations can be classified into five groups.
1.
Day preparations.
2.
Night preparations.
3.
Hand and body lotions.
4.
All-purpose products.
5.
Barrier creams.
Day preparations
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Day moisturizing products tend to be light, oil-in-water
emulsions which are designed to spread easily and rub
into the skin quickly.
They have evolved from the traditional vanishing
cream system which is an oil-in-water emulsion that is
based on high-quality stearic acid as the oil phase.
Commercial triple-pressed stearic acid consists of a
mixture of stearic and palmitic acid with a tiny amount
of oleic acid.
Partial neutralization of the fatty acid (16-20%) with a
base such as triethanolamine or potassium hydroxide
produces a soap which constitutes the emulsifier
system.
Day preparations
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These soap-based oil / water creams give a wet feel on
the skin when first applied. They do not rub in well and
appear soapy and white.
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Secondary emulsifiers such as self-emulsifying glyceryl
monostearate and other nonionic surfactants such as
polyethylene glycol esters and fatty alcohol ethers can
be used to prevent any skin dryness which may result
from use of the alkali-stearate soaps.
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Other emulsion stabilizers include the carbomers and
fatty alcohols such as cetyl alcohol. Cationic
surfactants, such as stearalkonium chloride, are used to
a lesser extent as emulsifiers. Because of their
substantivity
to the skin, they may be used to give an
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additional smooth skin feel after application.
Night preparations
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Products which are supposed to be left on
the skin overnight serve to provide vital
nutrients to the skin which may have been
lost during the day. These products, like
massage creams, tend to be water-in-oil
emulsions which are available as creams
and viscous lotions. Water-in-oil emulsions
tend to be less cosmetically elegant than
the oil-in-water types because of the
difficulty of rubbing them in; in addition they
are apt to leave a feeling of stickiness on
the skin.
Night preparations
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One of the advantages, that water-in-oil
systems have over their oil-in-water
counterparts, is that the continuous oil
phase has direct contact with the skin and
forms a protective film immediately without
any detergent action.
In this way the dispersed water particles are
trapped in the oil, by the water-in-oil
emulsifiers and the product is more
resistant to being washed off. Therefore
such products have remained popular with
people with dry skin.
Night preparations
Traditional night creams were
originally based on the beeswax,
borax and mineral oil systems.
 Today other waxes, vegetable oils
and silicone oils (instead of mineral
oil) can be used as emollients and coemulsifiers such as quaternary
ammonium salts or the volatile
silicones such as cyclomethicone.
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Night preparations
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A new range of silicone emulsifiers such as
lauryl methicone copolyol and cetyl
dimethicone copolyol have recently become
available. These can be used to produce
stable water-in-oil formulations with up to
74% water with little or no waxes. Therefore
the resulting formulations exhibit excellent
moisturizing properties combined with
improved aesthetics.
Hand and body lotions
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Products for use on the hands and
body tend to be similar in formulation
to the day moisturizers. They are
usually lotions and sometimes aerosol
mousses rather than creams, for ease
of application. This can be achieved
by increasing the viscosity of the
water phase with agents such as the
carbomers and cellulose derivatives.
All-purpose products
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As their name suggests, all-purpose creams
and lotions can be used as a moisturizer or
a cleansing cream on the face, hands and
body.
A simple, all-purpose cream can be
formulated with polypropylene glycol (PPG)
stearyl ether as the emollient and stabilized
with stearyl alcohol and nonionic
emulsifiers.
Protective products
(a) Simple hand lotions
 Hand preparations are available as creams, lotions and
gels. The skin on the hands, like that of the face, is
continuously exposed to the environment as well as
constant immersion in hot detergent solutions. If
adequate protective measures are not taken then the
hands can become extremely scaly, dry and inflamed,
resulting in an increased TEWL and impaired barrier
properties. Hand-care products are applied to re-hydrate,
smooth and leave a residual non-tacky protective film on
the skin.
 In addition to emollients, they can incorporate a healing
or soothing agent, such as allantoin, urea and lanolin
which confers some barrier properties to the product.
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Protective products
(b) Barrier creams
 Barrier creams, like hand creams, are
protective products. In addition, however, to
acting as moisturizers, they prevent external
materials from permeating the skin, such as
water, defatting solvents, soil and dirt.
 The formulation of barrier creams will be
determined by the type of external materials
from which the end-user requires protection.
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Protective products
Protection from water
 Formulations which exhibit water repellency
may be based on petroleum jelly , lanolin
and silicones.
 An aerosol mousse, as an alternative,
offers a product which is hygienic and easy
to apply. Kaolin may be included as a skin
protectant. Glyceryl monostearate (selfemulsifying grade) allows the product to be
easily washed off after use.
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Protective products
(c) Protection from soil and oils
 Non-oil soluble film formers such as gum acacia and
tragacanth or sodium alginate can be used to provide
oil repellency. Glycerin helps to plasticize the gum film.
(d) Deep engrained dirt on hands
 A vanishing cream-type formula can be used to
prevent the hands becoming ingrained with dust and
dirt. The effect is achieved by rubbing the soap into the
pores, which ultimately helps in the removal of soil
when the hands are washed.
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