Colloid

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Colloid Surface Phenomena Moisturizing Lotion

• Jason Ashbery
• Jonathan Danner
• Haohao Huang
• Leigh Vorreuter

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I. Product Design Considerations

• Customer Needs
• Heals dry skin
• Prevents dry skin
• Non-greasy
• Fast absorbing
• Non-irritating
• Non-scented or Scented
• Contains sun screen
• Prevent further aging of the skin
• Long lasting

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Product Design Considerations

• Different Types of Lotion
• For Dry Skin
• For Extra Dry Skin
• For Sensitive Skin
• Manufacturers
• Bath Body Works
• Suave
• Keri
• Bristol Meyer Squibb
• Clairol

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Product Design Considerations

• Product Specifications
• Shelf life
• Duration
• Consistency
• Viscous properties
• Fragrance
• Color
• Absorption
• Delivery systems of alpha hydroxide, sunscreen,
  moisturizing agents

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Components and Composition
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III. Colloids and Surface Interactions

• Functions of colloids in Moisturizing Lotion
• Diluent
• Humectant
• Smoothing aid
• Emollient
• Surfactant

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Liquid/ Liquid Emulsion

• An emulsion is formed when a mixture of two
  immiscible liquids are separated by a surfactant
  molecule.
• Oil-in-Water (O/W)
• Water-in-Oil (W/O)

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O/W and W/O Emulsion
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Phase Inversion of Emulsion

• Inversion from W/O to O/W
• Variables which lead to phase inversion
• Temperature Ethoxylate emulsifiers
• Surfactant composition Hydrophilic emulsifier
  concentration
• Water concentration Andrew Jergens Co.

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Effect of Amphiphiles on Delivery to the Skin

• Cationic Surfactants
• Effect of Temperature and Salt on micelle
  stability
• Effect of Temperature on delivery
• Pemulen Polymeric emulsifiers
• Triggered release mechanism upon contact with
  electrical charge of skin

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Traditional Surfactant Emulsion
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Pemulen Polymeric Emulsifiers
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IV. Product Attributes

• Shelf Life
• Emulsion stability is what determines the
  products shelf like
• If the emulsion becomes unstable the lotion will
  separate
• Adjusting the hyrophilic and lipophile balance of
  the emulsifier achieves the emulsions stability
• The emulsions are thermodynamically unstable due
  to its positive interfacial energy
• When the emulsion tries to reach it thermodynamic
  equilibrium it causes the emulsion to break up
  back to its component phase

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Product Attributes

• Shelf Life
• The delay of the component break up can be
  accomplished by adding specific mixed emulsions
  compiled of non-ionic and ionic surfactants and
  combined with fatty amphiphiles
• Examples can be found in Table 3
• Previously blended emulsifying wax into the the
  formulation can also help prevent the decay of
  the emulsions
• Examples can be found in Table 4

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Product Attributes
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Product Attributes

• Shelf Life
• The gel network theory of emulsion stability is
  why both emulsifiers and mixed wax help the shelf
  life period
• The emulsifiers stabilize the oil droplets by the
  formation of an interfacial film

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Product Attributes

• Consistency
• It is related to swelling properties and
  concentration of the a-crystalline gel phase
• When the a-crystalline form is in presence of
  very small quantities of ionic surfactants and a
  fatty aclohol and is dispersed in water the
  amount of swelling increases
• This leads to the swelling of the a-crystalline
  gel phase
• The water is in between the bilayers of the gel
  phase and when it swells the volume ratio of
  dispersed phase to the free continuous phase
  water increases

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Product Attributes

• Evaporation and Absorption
• When lotion is rubbed into the skin water
  evaporates and the oil droplets coalesce
• Coalescence occurs when the interfacial energy
  between substrates and adatoms is small
• The clusters can detach themselves from any given
  location on the surface and diffuse as entities
  over the surface
• The clusters behave more like liquid than solid
  crystallites

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Product Attributes

• Evaporation and Absorption
• After the application of the lotion the
  composition changes as the water and other other
  volatiles solvents evaporate
• A film stays on the skin as a protector and the
  nutrients are absorbed
• Absorption capacity increases with decreasing
  viscosity

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Product Attributes

• Viscosity
• Emulsion size and concentration determines the
  viscous properties
• At the same shear stress and droplet
  concentrations the viscosity of concentrated
  emulsions containing smaller droplets was
  significantly greater
• This suggests that electrostatic repulsion plays
  an important role in determining the rheology of
  concentrated emulsions

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Product Attributes

• Viscosity
• The droplets become closely packed causing the
  emulsions to be come rigid at lower
  concentrations for smaller droplets because of
  their effective volume fraction is greater
• This explains why low emulsifier concentrations
  are good for structured lotions
• Lotions are not suppose to be very thick and
  viscous

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Product Attributes

• Fragrance
• Fragrances are applied by collodial systems like
  emulsions
• The lipid part of the stratum corneum is
  organized in lamellar structures
• The lamellar liquid crystals in lotions contain
  the fragrance molecules
• The similarity of the configuration of the
  crystals in lotion compared to the stratum
  corneum is why it easy for the fragrance to be
  absorbed into the skin
• The location of the interlayer spacings and the
  geometrical characteristics play a big role on
  where the location of the fragrance is

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Product Attributes

• Improvements made to the skin
• Liposomes have positive effects on the appearance
  of the skin
• Improve cutaneous hydration, skin structure,
  depths of wrinkles
• Liposomes are spherical vesicles that have an
  aqueous cavity at their center
• They are used to carry water-soluble molecules
  and hydrophobic molecules
• Liposomes have been evaluated as delivery systems
  for drugs, vitamins and cosmetic materials

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Product Attributes

• Delivery Systems
• Particulate systems are very small particles that
  range from micrometers to millimeter
• These particles deliver essential active
  ingredients such as amino acids, plant extracts,
  minerals, vitamins, antioxidants, and UV
  protectants
• They also prolong the time during which the
  ingredient remains on the skin

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V. The effluence of structure of moisturizing
lotion (texture parameter) on its use properties,
and control of its physical properties
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Table 1. Texture profile
Primary parameter Secondary parameter Popular terms
Mechanical characteristics hardness Soft?firm?hard
Mechanical characteristics Cohesiveness Crumbly?crunchy?brittle
Mechanical characteristics viscosity Thin?viscous
Mechanical characteristics elasticity Plastic?elastic
Mechanical characteristics adhesiveness Sticky?tacky?gooey
Geometrical characteristics Particle size and shape Particle shape and orientation Particle size and shape Particle shape and orientation Gritty, grainy, coarse, etc. Fibrous, cellular, crystalline, etc.
Other characteristics Moisture content Dry?moist?wet?watery
Other characteristics Fat content Oiliness greasiness oily greasy
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Table 2. Texture profile parameter used in the
skin care product evaluation
Stage of evaluation Skin care product attribute and definite Texture profile parameter
PICK-UP, product removed from container, product poured or squeezed from bottle onto fingertips, or product lifted from jar with forefinger THICKNESS-perceived denseness of product. Evaluated as force required to squeeze between thumb and forefinger. Rated as thin-medium-thick. Or CONSISTENCY-perceived structure of product. Evaluated as resistance to deformation and difficulty of lifting from container. Rated as light-medium heavy. Viscosity for lotions
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Table 2
RUB-OUT (application), spread of product over and into skin with fingertips using gentle circular motion at a rate of two rub per second for a specified period of time, depending on the product. SPREADABILITY-ease of moving product from point of application over rest of face. Evaluated as resistance to pressure. Rated or described as slips-very easy to spread glides-moderated easy drag-difficult to spread ABSORBENCY-Rate at which product is perceived to be absorbed into skin. Evaluated by noting changes in character of product and in amount of product remaining (tactile and visual) and by changes in skin surface. Rated slow-moderate-fast. Viscosity, cohesiveness, springiness, gumminess, adhesiveness Other characteristics (oil and water content of product)
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Table 2
AFTER-FEEL (and appearance), evaluation of skin surface with fingertips, visually and kinesthetically immediately after product application and possible at varying intervals thereafter. AFTER-FEEL Type and intensity of product residue left on skin changes in skin feel/ Product residue is described by type, i.e. film(oily or greasy), coating(waxy or dry), flaky or powdery particles the amount of such residue is identified as slight-moderate-large. Skin feel is described as dry (taut, pulled, tight) moist(supple, pliant), oily(dirty, clogged). Other sensations are also noted and identified where applicable, i.e. clean, stimulated, irritated, etc. Other characteristics-(oil and water content) Geometrical characteristics-(gritty, powdery, etc.)
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1. Factors influencing the lotion physical
parameter

• (1). THE EMULSIFIER
• The emulsifier is the most important role in
  the emulsion in producing the characteristic flow
  properties.

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(2) THE DISPERSE PHASE

• There are many parameters related to the disperse
  phase or internal phase that exert rheological
  changes in emulsions, including nature of the
  oil viscosity of the oil particle size
  particle size distribution and particle shape.
  Particle size and particle size distribution also
  depend on the emulsifier concentration.

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(3) THE CONTINUOUS PHASE

• The rheological behavior of a lotion is most
  often determined by the rheology of the
  continuous phase.

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(4) PHASE VOLUME RATIO

• Generally, it has been found that the rheological
  parameters of an emulsion increase with creaseing
  the phase volume ratio.

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2. The effects on the behavior of lotion during
lotion processing

• (1) Mixing
• (2) Heating and Cooling
• (3)Homogenizing

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(1) Mixing

• Mixing is necessary to blend a water phase and
  oil phase into an lotion
• A high amount of mixing energy can decrease the
  particle size of the dispersed phase and hence
  affecting the emulsion viscosity
• lotion may be shear sensitive to some degree and
  mixing can be used to get the desired product
  viscosity by properly manipulating the mixing
  variables

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(2) Heating and cooling

• Heating is generally not a problem in cosmetic
  processing because the product is usually fluid
  at elevated temperatures
• Cooling is more commonly a problem with cosmetic
  emulsion because it generally increases product
  viscosity greatly
• Cooling has a more important relationship to
  final product viscosity because of its effect on
  crystallite size and dispersion

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(3) Homogenizing

• The cosmetic industry usually resorts to
  homogenization for dispersing solids and
  insoluble liquids in a liquid phase and reducing
  the dispersed particles to a minimum size

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VI. Manufacturing Process

• The objective is to disperse one liquid within
  another in an extremely fine form to make certain
  that separation due to settling either does not
  occur or takes place very slowly.
• Does not normally involve any extraction or
  chemical reaction.

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A Few Parameters that may influence liquid-liquid
emulsion formation

• Shear rate
• Sufficient stabilizers need to be present to
  maintain the smallest droplet size produced for
  long periods of time.
• Blend time and standard deviation of circulation
  time.
• These along with many other parameters make it
  difficult to specify a mixing process based on
  desired droplet size. Most predictions are based
  on existing data.

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Pilot Scale Manufacturing Process (US Patent
6,017,548)
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Federal Rules and Regulations

• GMPs Primary objective is to ensure that
  manufacturers provide consumers with safe and
  effective products.
• Parts 210 and 211 apply to manufacturing of drugs
  and finished pharmaceuticals.
• Part 210 contains a basic overview and some
  definitions that are used in Part 211.

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Part 211

• Gives a description of responsibilities of the
  quality control unit.
• States that proper training procedures must be in
  place.
• Buildings and Facility requirements
• Cleaning requirements- Rooms and Equipment
• Proper labeling and storage of materials
• Batch Records

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Marketing Considerations

• Packaging aesthetics
• Fragrance
• Color of Lotion
• Shelf Location