It compiles the brief introduction of cream along with their uses and emulsion and some preservatives of emulsion

1. SKIN CREAMS
PALAK AGRAWAL
M.PHARM
RCPSR

2. Introduction
A cream is a topical preparation
usually for application to the skin.
Creams for application to mucus
membranes such as those of the
rectum or vagina are also used.
Cream may be considered
pharmaceutical products as even
cosmetic creams are based on
techniques developed by pharmacy
and unmediated creams are highly
used in variety of skin conditions.

3. Continued
Cream are semi-solid emulsion that
are mixtures of oil and water. They are
divided into two types; oil-in-water
(o/w) creams which are composed of
small droplets of oil dispersed in a
continuous aqueous phase, and
water-in-oil (w/o) creams which are
composed of small droplets of water
dispersed in a continuous oily phase.

4. Continued
 Oil-in-water creams are more comfortable
and cosmetically acceptable are as they are
less greasy and, more easily washed off
using water.
 Water-in-oil creams are more difficult to
handle but many drugs which are
incorporated into creams are hydrophobic
and will be released more readily from a
water-in-oil cream than an oil-in-water cream.
 Water-in-oil cream are also more moisturizing
as they provide an oily barrier which reduces
water loss from the stratum corneum, the
outmost layer of the skin.

5. Continued
Fig: Comparison between old skin and healthy
skin

6. Use of creams
 The provision of a barrier to protect
the skin.
 This may be a physical barrier or a
chemical barrier as with sun screens.
 To aid in the retention of moisture
 Cleansing
 Emollient effects.

7. Emulsion
An emulsion is a mixture of two
immiscible substances. Once
substance (the dispersed phase) is
dispersed in the other (the continuous
phase).
Example of emulsion: Butter and
margarine, espresso, mayonnaise.
Emulsions tends to have a cloudy
appearance, because the many
phase interface scatter light that
passes through the emulsion.

8. Continued
Emulsion are part of a more general
class of two phase system of matter
called colloids. Although the terms
colloid and emulsion are sometimes
used interchangeably, emulsion tends
to imply that both the dispersed and
the continuous phase are liquid.
There are three types of emulsion
instability:

9. Continued
 Flocculation, where the particles form
clumps;
 Creaming, where the particles
concentrate towards the surface of the
mixture while staying separated; and
 Breaking, where the particles
coalescence and form a layer of liquid.

10. Emulsifier
 An emulsifier is a substance which
stabilizes an emulsion. Example of
food emulsifier are egg yolk and
mustard , where a variety of chemicals
in mucilage surrounding the seed hull
act as emulsifier; proteins and low
molecular weight emulsifier are
common as well. In some cases,
particles can stabilize emulsion as well
through a mechanism called Pickering
stabilization.

11. Preservatives for cosmetic
emulsion
Preservatives for cosmetic emulsion
Group Preservatives Action
Acids and acid salts •Benzoic acid
•Propionic acid
•Sorbic acid and its
salt
Antifungal agent
Aldehydes •Formaldehyde
•Glutaraldehyde
Broad spectrum
preservatives
Phenolic compounds •Cresol
•Phenol
•Chlorothymol
•O-phenyl phenol
Broad spectrum
preservatives
Quaternary
ammonium
compounds
• Benzethonium
chloride
•Benzalkonium
chloride
Broad spectrum
preservatives