Cosmetics : hair dyes Chap. 4. Food, Drug &...

Chap4- 1

Chap. 4. Food, Drug & Cosmetics

- Cosmetics : hair dyes

- Pharmaceutical applications

Chap4-

- Structure of Human Hair- Hair Color- Permanent Hair Coloring- Temporary Hair Coloring- Semi permanent Hair Coloring- Evaluation

Cosmetics : hair dyes

2

(피질)

(모수질)

Chap4- 3


Chap4- 4

- Human Hair is a protein fiber made of two layers. The inner layer calledcortex contains melanin. Melanin is a pigment which gives your hairshades of blonde, black, auburn or brown.

- Cortex is covered by another layer called cuticle. Cuticle providesprotection to cortex and luster to your hair.

- Cuticle is inert in nature so it cannot biologically or chemically absorbany color.

Cosmetics : hair dyesStructure of human hair

Chap4- 5

Structure of human hair

β-layer

Cell membraneA-layer

ExocuticleEndocuticle

β-layerδ-layer

Cell membraneChap4- 6


- The hair shaft is divided into four main distinct structures: cuticle, cortex, cell membrane complex (CMC), and the medulla.

- The cuticles (amorphous and protein material) are the most external part of the hair strand and ensure chemical resistance.

- These cuticles carry out the function of regulating the amount of water in the hair structure, which keeps its physical properties.

- It contains six to ten layers of overlapping cells in the longitudinal direction of the fiber.

- The damage to the cuticle can be caused by weather, mechanical friction such as combing and brushing or the excessive use of shampoo and other inappropriate cosmetics.

Structure of human hair

cuticle

Chap4- 7

Cosmetics : hair dyesStructure of human hair : cuticles

- Each cuticle cell contains an external thin membrane (5~10nm) formed by a layer of fatty acid connected to the protein layer through thioester bonds, which generates cysteine residues responsible for the apparent hydrophobic character of the fiber.

- The outermost surface of the cuticle cells are covered by a layer of covalently bound fatty acids, a major component of which is 18-methyleicosanoic acid (18-MEA).

- 18-MEA is an unusual branched-chain fatty acid, covalently bound, via thioester or ester linkages, to the cuticle surface of hair.

- The absence of 18-MEA is one of the reasons for an increase in interfiber friction, and it may have an influence on sensory perceptions of hair, such as a dry feel and difficult combing

Chap4- 8

Cosmetics : hair dyesStructure of human hair : cuticles

Hair that has lost 18-MEA

Healthy hair that retains 18-MEA; the water droplet rolls over the hair, confirming its smoothness

Chap4- 9

Cosmetics : hair dyesStructure of human hair : cuticles & CMC

- A-layer : 120nm thick with a high content of cysteine and highly cross-linked

- Exocuticle (B-layer) : also rich in cysteine and occupying about the half of the cell volume.

- Endocuticle : a layer with a low content of cysteine and relatively high levels of basic (lysine, arginine) and diacids (aspartic and glutamic acids) amino acids.

- Cuticular CMC : present in between the cuticle cells and made up of polysaccharides and lipids.

β-layer

Cell membraneA-layer

ExocuticleEndocuticle

β-layerδ-layer

Cell membrane

Chap4- 10

Cosmetics : hair dyesStructure of human hair : CMC

(Cuticular CMC)

(Corticular CMC)

Chap4- 11

Cosmetics : hair dyesStructure of human hair : cuticular CMC

- It is present in between the cuticle cells and made up of polysaccharides and lipids (18 MEA)

- It acts as a cement between the cuticle layers and holds them together but does not give any toughness to the cuticle.

CMC

- The CMC and the endocuticle are usually referred to as non-keratinized regions because they have a low level of sulfur amino acids.

- Helps in the active transfer of molecules from cuticle to cortex.

Chap4- 12

Cosmetics : hair dyesStructure of human hair : corticular CMC

- consisting of cell membranes and adhesive material that “glue” or link the cortical and the cuticle cells

- Cortical cells are separated by CMC of the cortex.

- The cortical CMC is similar to cuticular CMC but it is not as regular as cuticular CMC.

- The CMC are important pathways to the diffusion of molecules(ex. water) to inner regions of the hair fiber

- It is also responsible for the hair’s natural moisture, making it bright, transparent, and hydrated.

Chap4- 13

Cosmetics : hair dyesStructure of human hair : corticular CMC

- composed of lipids, proteins, polysaccharides, and ceramides

- But does not contain 18-MEA.

Chap4- 14

Cosmetics : hair dyesStructure of human hair : cortex

- The cortex is the principal component of the hair, consisting of cylindrical cells of about 1 to 6 μm of thickness and 100 μm of length.

- It forms the matrix where other proteins and keratin are located, and composes the larger part of the fibrous mass of human hair, being formed by intracellular and intercellular material.

- The cortex represents 90% of its total weight and consists of cells filled with keratin, with an organization that provides mechanical properties to the fibers.

- The cortical cells, adjacent to the cuticle, are flatter and contain less sulfur than the cells inside the cortex, which are rich in cystine (two cysteine), amino acids, lysine and histidine, in addition to the melanin granules.

Chap4- 15

Cosmetics : hair dyesStructure of human hair : cortex

- Although there are amorphous regions, the matrix presents small parts with structural organization.

- It exhibits keratin macrofibrils aligned in the direction of the hair strand and melanin granules which are responsible for the hair color and its photo protection.

- The matrix comprises the major structure of the hair and contains a high concentration of disulfide bonds.

- It presents considerable swelling when in contact with water and forms a lightly cross-linked gel structure.

Chap4- 16

Cosmetics : hair dyesStructure of human hair : medula

- The medulla is the innermost region and its presence along the hair is usually discontinuous or even absent and does not interfere with the hair structure.

- The medulla can be empty or filled with sponge keratin, can serve as a pigment reservoir, and can contribute to the brightness of the hair.

- The lipid concentration inside the medulla is bigger than anywhere else in the hair.

Chap4-

Hair color (Melanin)

- Hair is mainly keratin, the same protein found in skin and fingernails.

- Hair is colored by pigment particles embedded in the cortex (~3%).

- Hair color is the pigmentation of hair follicles due to two types of melanin: Eumelanin and Pheomelanin

- The natural color of hair depends on the ratio and quantities of two proteins

17


Chap4- 18

Chap4-


- Eumelanin, which has two subtypes of black or brown, determines the darkness of the hair color.

- A low concentration of brown eumelanin results in blond hair, whereas a higher concentration of brown eumelanin will color the hair brown.

- High amounts of black eumelaninresult in black hair, while low concentrations give gray hair.


19 Chap4-


- Pheomelanin colors hair orange , yellow and red. All humans have some pheomelanin in their hair.

- Pheomelanin is more chemically stable than black eumelanin, but less chemically stable than brown eumelanin, so it breaks down more slowly when oxidized.

- As the pheomelanin continues to break down by bleaching, the hair will gradually become orange, then yellow, and finally white.


Black melanin eumelanin monomer

Brown melanin eumelanin monomer

Pheomelaninmonomer

20

Chap4- 21

Biosynthesis of precursors to Melanin


Chap4- 22

Melanin formation


- A mutation that results in a non-functional enzyme anywhere along the pathway will cause a failure to produce one or both forms of melanin : → Albinism

Chap4-

Chemical structure ofEumelanin

23

Chemical structure ofPheomelanin

(part of the structural formula)

The arrows denote where the polymer continues



Chap4- 24

Asian vs Westerner


Asian Westerner

Fineness(㎛)

Korea, Japan ~80Taiwan, China 80~Strong and tough

USA 50~55German 55~60Fine and soft

Color Major : EumelaninCoarse particle, Much amountDark brown

Major : PheomelaninFine particle, Small amountBlonde,

• Japanese Black 2• Italian Brown 1.1• Irish Red 0.3• Scandinavian Blond 0.06• Albino 0

Eumelanin contents (%)

Chap4- 25

Classification : color resistance


Hairdye

Temporary

Semi-permanent

Demi-permanent

Permanent

dye deposition on cuticlesex. Acid dyes (removed with a single shampooing)dye deposition with a little dye penetration into the cortexex1. Basic(cationic) dyesex2. Basic dyes + nitroaniline dyes(3~6 washes)

ex.Oxidation dye precursor+ semi-permanent dye(up to 20 washes)

Different alkalizing

agentex. Oxidation dyes based on color precursors(permanent)color resistance ↑

(↑ no use of H2O2)(↓ use of H2O2)

Chap4-

• 1883 Discovery that p-phenylenediamine

• 1888-1897 Scope of substituted benzenes that can be used to color hair extented; Use of hydrogen peroxide as an oxidant

• 1898-1930 Additional 79 hair dye patents issued

• 1906 Founding of L’oreal

• 1931 Founding of Clairol

26

Synthetic hair color


Chap4- 27

Permanent hair coloration : an oxidative process mechanism


1st step : oxidation of p-phenylenediamine to the quinonediimine derivative

2nd step : the attack of this quinonediimine on the coupler by electrophilic aromatic substitution

3rd step : the product from the quinonediimine-coupler reaction oxidizes to the final hair dye.

Coupling base(Dye precursor, intermediate)

Reaction modifier (coupler)

final hair dye

Chap4- 28

Cosmetics : hair dyesPermanent oxidative hair dyeing : coupling bases (intermediates)

- Two major compounds are used such as p-phenylenediamine and p-aminophenol.

NH2

NH2

p-phenylenediamine

p-aminophenol

Toluene-2,5-diamine

N,N-Bis(2-hydroxyethyl)-p-phenylenediamine

- Bases are aromatic compounds derived from benzene, substituted by at least two electron donor groups such as NH2 and OH in para or orthopositions to confer the property of easy oxidation, acting as a color developer.

Chap4- 29

Cosmetics : hair dyesPermanent oxidative hair dyeing : mechanism of intermediates

- The first step in oxidative hair dyeing involves oxidation of the primary intermediate with alkaline hydrogen peroxide.

- The nature of the specific reactive species involving hair coloration with p-phenylenediamine is still under debate: p-benzoquinonediimine and its conjugated acid(pH 7~10) has been proposed : attacks dye-coupling agent.

Diiminium ion

p-phenylenediamine p-aminophenol

Quinoniminiump-benzoquinone diimine

Chap4- 30

Cosmetics : hair dyesPermanent oxidative hair dyeing : Health concerns

- Skin sensitization: a strong potential skin sensitizer.the 5th most common skin allergen.

- Cancer: have long been suspected of being carcinogenic. For example, they are linked to increased incidence of bladder cancers.

- Mutagenicity: When P-phenylenediamine reacts with hydrogen peroxide it can form a mutagenic, or DNA-altering, substance called Bandrowski’s base. Bandrowski’s base has been shown to be strongly mutagenic and possibly carcinogenic.

- Organ system toxicity: When ingested, p-phenylenediamine can cause respiratory distress and renal failure. It causes swelling in the upper respiratory tract and larynx which causes respiratory distress. If the poisoning is severe it enough it can also cause renal failure and can ultimately be fatal.

p-phenylenediamine

Chap4- 31

Cosmetics : hair dyesPermanent oxidative hair dyeing : Health concerns

Allergy Test

• Wash small area inside arm at the elbow• Apply dye solution • Leave area of this skin uncovered for 24hours• If itching, redness, burning, other allergic symptom do not use the

product

Chap4- 32

Cosmetics : hair dyesPermanent oxidative hair dyeing : reaction modifier (coupler)

- Reaction modifiers, also called couplers, are aromatic compounds derived from benzene and substituted by groups such as NH2 and OH in the meta position, which does not present easy oxidation by H2O2.

- They do not produce significant color alone but can modify them when used as primary intermediaries and oxidants.

- There are many reaction modifiers available in the market, and some of the most important are shown next page.

A, B = NH2 or OH

Chap4- 33

Cosmetics : hair dyesPermanent oxidative hair dyeing : reaction modifier (coupler)

resorcinol

4-chlororesorcinol

2-amino-hydroxyethylaminoanisole sulfate

2-methylresorcinol

m-aminophenol p-amino-o-cresol(4-amino-2-hydroxytoluene)

2,4-diaminophenoxyethanol HCl

O

NH2NH

HO

SO

OHHOO

pyrogallol p-(2-hydroxyethylamino)-o-cresol

m-phenylenediamine

4-methyl-m-phenylenediamine

NH2

NH2

O

4-ethoxy-m-phenylenediamine

Chap4-

Dark blue

Red

Light brown

34

NH2

NH2

N

N

HH

H

[O]

NH2

NH2

NH2

OH

OH

OH

N

NHH2NH2N

N

OH2NH2N

N

OHOH2N

N

OHOH2N

HN

NH2

NH2

NH2

Cosmetics : hair dyesPermanent oxidative hair dyeing : general pathway

Chap4- 35

Cosmetics : hair dyesSome products formed in oxidation dye reaction

① Bandrowski’s Base (PPD)

② Polyindophenols (Resorcinol + PPD)

③ Indamines (m-Phenylenediamines)

④ Indo Dyes (m-Aminophenols)

⑤ Others : Indophenols (Naphtol or hydroquinone)

①②③④⑤

Chap4- 36


① Bandrowski’s Base

• Diimine condenses with p-phenylenediamine -> Bandrowski’s base (brown-black indo dye)

• End product of an undesirable side reaction in hair dyeing• Not main colorant of hair dye⇒Diimine<<diiminium ion (reactive↑)• Formation of Bandrowski’s base in modern oxidation dyes↓

Chap4- 37


② Polyindophenols (Resorcinol + p-Phenylenediamine)

• Resorcinol : most oxidation dye couplers• Resorcinol + p-Phenylenediamine = polyindophenols (Bandrowski’s

base is prevented)• Di-, tri-nuclear species : green pigment• Polymeric polyindophenol : brown pigment

Chap4- 38


② Polyindophenols (Resorcinol + p-Phenylenediamine)

HN

HO OH2N

H

N

HO OH2N

NH2

NH2

N

NHH

H

Diiminium ion

oxidation

Resorcinol anion

Indophenol

1,4 additionPPD

HN

HO OH2N

HN

H

NH2

N

HO OH2N

HN

NH2

trinuclear green pigment

Brown polymericpolyindophenols

OH

O

PPD

oxidation

Oxidation

41

2 3

Chap4- 39


③ Indamines (m-Phenylenediamines)

• 4-methoxy m-phenylenediamine : important dye coupler

• R : methoxy → relatively stable dye

• Unstable dye in high humidity → red 2,8-diaminophenazines

NH2N NH2

Blue dye

HN

H2N NHH2N

H

NH2

NH2

N

NHH

H

Diiminium ion

oxidation

PPD

N

H2N NHH2N

R

substituted 2-aminoindamine

H

NH2H2N

R

substituted m-pheylenediamine

R

NH2H2N

R

oxidation

Chap4- 40


④ Indo Dyes (m-Aminophenols)

If R= Alkyl : stop at dimer stage

If R= H : react with PPD → trimeric indo dye

Amino -Block! Phenolic - Block!

Chap4- 41


⑤ Others

NH2

NH2

N

NHH

H

Diiminium ion

oxidation

PPD

Indonaphtol

1-Naphtol

oxidation

O

N

O H

NH2

O

N

NH2

HH

1,4-addition& oxidationResorcinolor PPD

trinucleardye

Chap4- 42


⑤ Others

HN

RH2N

H

NH2

NH2

N

NHH

H

Diiminium ion

oxidation

PPD

N

RH2N

Hydroquinone

oxidation

OH

OH

R

O

OH

O

OH

N

NH2NOH

OHNH2

if R=H

Trinuclear species

Chap4- 43

Cosmetics : hair dyesReaction of oxidation dyes

• Oxidation dye products = five to seven or more ingredients (precursors or couplers)

• Nucleophilic groups in hair + indo dye : covalently bonding dye molecules to the hair

• Penetration (precursors and couplers) : limited to the outer of hair

• Condensation reaction (fast) >> diffusion (slow)• Condensation products (higher polymeric dyes by

repeated 1,4-addition followed by oxidation) are resistant to shampooing.

Chap4-

Component Function

EmulsifierFormation of non dripping cream…

Consistency Giving FactorsSurfactants Enhance hair wetting and homogeneous

dispersion of dyesFatty acid Cleansing a kind of oil in the surface of hairCare Additives Hair care functionDyes (Intermediates, Couplers) Change the primary colorAlkaliex. ammonia(form of ammonium hydroxide), monoethanolamine(contains water) or sodium silicate (solid form-powder)

- Separate the cuticle and allow the dye to penetrate the cortex of the hair

- to promote the proper pH value for the beginning of the oxidation reaction.

Antioxidants (reducing agent) Prevent dyes oxidization before use

44

Cosmetics : hair dyesPermanent oxidative hair dyeing : phase 1 (precursor-coupler base)

Chap4-

1. Consistency Giving Factors Wax – Cetostearyl alcohol

(emulsion stabilizer)

2. Surfactants*HLB 15-16 + HLB 10-11 + HLB 4-5

3. Fatty acid : Oleic acid

4. Care Additives : proteins, plant extracts

5. Alkali : Ammonia, Monoethanolamine

6. Antioxidants : Sodium metabisulfite(MBS), Erythorbic acidThioglycolic acid

45

Cosmetics : hair dyesPermanent oxidative hair dyeing : phase 1

* HLB(hydrophilic-lipophilic balance) is a measure of the degree to which it is hydrophilic or lipophilic

Chap4- 46


Sodium lauryl sulfate(surfactant)

Oleic acid(fatty acid)

ex. The Nonoxynols help to form emulsions by reducing the surface tension of the substances to be emulsified

Cetostearyl alcohol (fatty alcohol,

emulsion stabilizer)

Chap4- 47


Sodium metabisulfite(anti-oxidant)

Thioglycolic acid (anti-oxidant)

Monoethanol amine(alkai)

Erythorbic acid(anti-oxidant)

Ammonia(alkai)

NH4OH ↔ NH3 + H2O

Chap4- 48


Alkalizing compounds :

- to promote the proper pH value for the beginning of the oxidation reaction.

- Monoethanolamine (MEA) : for demi-permanent dyeing• does not oxidize the melanin.• suitable for maintenance of similar shades or to dark hair.

- Ammonia : for permanent dyeing• it is possible to cover 100% of white hair and to remove the natural pigments present in hair as the melanin.

• This type of dye is considered permanent because, after the formation of the colored polymer in the inner of the cortex, its complete removal is not possible.

Chap4-

Component Contents(%) FunctionOxidizing agentex. H2O2 (30%) 50

Oxidize melanin and intermediate.

Stabilizerex. Na2SnO3·3H2O,Pentasodium pentetate

1Stabilize hydrogen peroxide during storage.

Surfactant / Acid 33 Make pH of goods below 4. (ex. H3PO4)

water 16 -

49

Cosmetics : hair dyesPermanent oxidative hair dyeing : phase 2 (oxidizing base)

dodecyl benzene sulfonatePentasodium

pentetate

Usually used in the form of emulsion : “creamy hydrogen peroxide”

Chap4- 50

Cosmetics : hair dyesPermanent oxidative hair dyeing : Vehicles

- The oxidative dye in the form of emulsion is the highest selling product in the market, but other carriers are available such as gels, solutions (liquid), and powders.

- The preparation of the emulsion : • begins with adding the dye mixture to the reducing agents, antioxidants, and ammonium hydroxide in 20% of the aqueous phase.

• The other 80% of water is added in a manufacturing tank and heated to 70oC under constant agitation.

• After reaching the temperature, all the wax and the emulsifying agents are added, maintaining a constant stirring until cooling to 40oC, when the remaining 20% of the water previously prepared is added.

Chap4- 51

Cosmetics : hair dyesExample of Formulation – Cream, phase 1Phase Component % FunctionI. LANETTE® O Cetearyl Alcohol 16,6 Consistency giving factor

EUMULGIN® B2 Ceteareth-20 5,5 EmulsifierEUMULGIN® CS 3 Ceteareth-3 3,5 EmulsifierCOMPERLAN® KD Cocamide DEA 2 ThickenerPOLYQUART® H 81 2 Conditioning agent

PEG-15 Coco PolyamineII Water, de-ionized ad 100IIa Propylene Glycol 5 Solvent

DyeIII Water, de-ionized 10

Sodium Sulfite 0,5 AntioxidantSodium Hydrosulfite 0,25 AntioxidantAscorbic Acid 0,2 AntioxidantEDTA Tetrasodium EDTA 0,2 Chelating Agent

IV Ammonia, 25% 7 Alkali

Preparations in the laboratoryHeat phase I to 70-75 °C. Heat phase II to the same temperature and add to phase i mixing. Add phase IIa and phase III and allow to cool while stirring (homogeneize). Add Ammonia below 30 °C.

Chap4- 52

Cosmetics : hair dyesExample of Formulation – Gel, phase 1

Phase Component % Function

I. DEHYDOL® LS 2 DEO N Laureth-2 24 gelling agentDEHYDOL® LS 3 DEO N Laureth-3 7,2 gelling agentCOMPERLAN® KD Cocamide DEA 4,8 ThickenerCOMPERLAN® OD Oleamide DEA 1 ThickenerIsopropyl Alcohol 10,6 SolventButoxyethanol 6,5 SolventEDENOR® Ti 05 Oleic Acid 2 Gelling agentTEXAPON® MLS MEA Lauryl Sulfate 3 TensideWater, de-ionized ad 100Ascorbic Acid 0,2 AntioxidantSodium Sulfite 0,5 AntioxidantdyeMonoethanolamine Ethanolamine 2 AlkaliGLUADIN® R Hydrolyzed Rice Protein 1 Active ingredient

Preparations in the laboratoryAdd the ingredients in the order as shown. Mix at room temperature.

Chap4- 53

Cosmetics : hair dyesExample of Formulation – phase 2

Phase Component % Function

I. Water, de-ionized ad 100 EMULGADE® F Cetearyl Alcohol (and)

PEG-40 Castor Oil (and)Sodium Cetearyl Sulfate 3 Cream base

CETIOL ® PGL Hexyldecanol (and) Hexyldecyl Laurate 0,2 Emollient

TURPINAL SL Etidronic Acid 0,2 Sequestering Oxyquinoline 0,02 Peroxide stabilizerHydrogen Peroxide 15,4 Bleaching

Preparation in the laboratoryHeat water to 80 °C, add Emulgade F while stirring; after homogeneous dispersion add Cetiol PGL and Turpinal SL. Allow to cool while stirring. Add the remaining components at R.T.

Chap4- 54

Cosmetics : hair dyesPermanent oxidative hair dyeing : parameters

- Various parameters may affect the color formation in the hair dyeing process, such as pH, pause time, hair keratin, and purity of the dye molecule, amongst others.

- The variation of the pH value directly influences the reaction rate because a more alkaline pH favors the reaction and facilitates the cuticle opening, allowing the penetration of molecules into the cortex.

- The pause time is essential for a complete reaction between the bases and reaction modifiers to occur: the product must be in contact with the hair from 30 to 45 min after application because it is then possible to ensure color reproduction and durability to washing.

Chap4- 55


- Simultaneously remove natural pigment while adding artificial color in one application

- resulting in a natural-looking color

- Used to match, lighten, and cover gray hair

- Hair is not coated so other chemical treatment is possible.

- penetrates to the cortex layer of the hair

Advantages

Permanent oxidative hair dyeing : parameters

Chap4- 56


- Patch test must be given prior to every application.

- Due to chemical change the hair must reconditioned and carefully maintained.

- Natural pigment is altered.

- To remove the effects of a tint A tint remover Re-tint to camouflage Cut the hair to remove it

- Color can fade with time & shampooing, to off-color or harsh tones

Disadvantages

Permanent oxidative hair dyeing : parameters

Chap4-pH

0 2 4 6 8 10 12 14

Swel

ling(

%)

20

25

30

35

40

45

50

57


pH control (alkali): Ammonia, Monoethanolamine

pH effect on hair swelling

Chap4- 58

Cosmetics : hair dyesDye penetration pathway

Transcellular Diffusion

Intercellular Diffusion

Cortex(~3% Melanin)

(1) Transcellular diffusion : diffusion across cuticle cells through both high and low cross-linked protein.

(2) Intercellular diffusion : penetration between cuticle cells through the intercellular cement and other proteins that are low in cystine content (low cross-link density regions). → the preferred route for entry

Chap4- 59

Cosmetics : hair dyesDye penetration pathway : rate of diffusion

- Size of the particles : the smaller the faster

- Temperature (e.g. kinetic energy) : the hotter the faster

- The concentration gradient: the higher the faster

- State of the particles: gas > liquid > solid

- Distance or thickness of the exchange surface : the thinner the

faster

- Surface area available : the larger the faster

Rate of diffusion depends on

Chap4-

Destroy melanin and lighten hair color

Peroxide bleaching- More effective at higher pH- Ammonia > monoethanolamine (MEA)

Peroxide/Persulfate(ammonium, potassium) - Extensive bleaching(black to blond)- Cause high hair damage

Inherent in all permanent hair dye product

60

Cosmetics : hair dyesHair bleaching

Chap4-

Bleaching,

61

Cosmetics : hair dyesHair damage by bleaching

The active bleaching component in bleaching with Hydrogen Peroxide is Perhydroxyl ion

Hair Damage,

Chap4- 62

- Cuticle is inert in nature so it cannot biologically/chemically absorb any color.- Most of the chemical dyes contain bleaching agents(peroxide+ammonia)

which damage the outer most layer and create capillaries in hair shaft.- Then chemical color fills these capillaries, enter in the inner layer and remain

stuck inside, as permanent color.- The next application again does the same on hair shaft. This results in loss of

strength, roughness and permanent damage to hair.

Cortex cell

medulla

melanin

Hair coloration

Dye penetration pathway

Chap4- 63

Cosmetics : hair dyesMelanin Oxidation

The peroxide oxidizes the natural pigment in the cortex so that they are colorless

Chap4-

pH7 8 9 10 11 12 13 14

Ble

achi

ng

1

2

3

4

5

6

Hydrogen peroxide(%)0 5 10 15 20 25 30 35

Ble

achi

ng

0

1

2

3

4

5

6

7

8

64

pH 7

pH 10

Cosmetics : hair dyesHair bleaching ability

The ammonia enables the bleach & peroxide penetrate into the cortex layer

Chap4-

* pH 10.5 (During dyeing) pH 8.3(After dyeing)

pH 9.5 pH 10.5 pH 11.5

Bleaching ↓Dyeability ↑

Hair damage ↓Fading ↓

Grey coverage – Low pH for higher dyeability Fashion Color – High pH for higher bleaching

65

Cosmetics : hair dyespH effect on dyeability

Bleaching ↑Dyeability ↓

Hair damage ↑Fading ↑

Chap4- 66

Cosmetics : hair dyesTemporary Non-oxidative hair dyeing

- This type of dye does not have the power of whitening the hair strand and, therefore, it is indicated only to add new nuance and not to change its color.

- In white, blond or bleached hairs, it is possible to add a new color with a more noticeable effect because the hair strand’s background color allows the visualization of the new applied color.

- The temporary non-oxidative dyeing has a reduced permanence time on the fiber, leaving the hair after the first shampoo washing because dye presents high molecular weight and deposits on the hair surface without the capacity of penetrating the cortex.

Chap4- 67


- The temporary dye can be used for adding colorful reflections, removing the yellowish effects of the white hair, and covering a small quantity of white hair. (white hair less than 15%)

- Usually acid dye with high molar mass : contain anionic characteristics and are selected to allow the maximum solubility in water and the minimum penetration in hair so it is removed in the first washing.

- They are presented as shampoo, gel, emulsion and solution (liquid) with two different forms of application: continuous application (progressive) or single application, with one wash at the end of the application process to remove the unabsorbed dye excess on the hair strand.

Chap4- 68


- Color rinses :Last from shampoo to shampooCertified colors (FDA approved )Coat the hair shaft

- Color-enhancing shampoo :Consist of shampoo & mixed with colorantsBlend color tones / Brighten / Impart slight color /Neutralize unwanted shades

- Color mousses and gels : Slight color or dramatic effectsStyling aids

- Crayons, sprays & mascara :Crayons : Retouch new growth / Lipstick Sprays : Usually bright, party colors, applied directly to dry hairMascara : Facial makeup

Chap4- 69

Cosmetics : hair dyesTemporary Non-oxidative hair dyeing : acid dyes

- Compositions : • Consists of a mixture of color additives, (next table) similar FD&C or D&C colors.• 2~5 color ingredients to achieve the desired color.(2 color ingredients) tints for gray (4~5 color ingredients) reds, brown, black

- Dyes : • Generally larger molecular species than semipermanent hair dye• Anionic or acid dyes – similar to wool dyeing

cf. wool dyeing temp. ~100°: too high for human hair dyeing• Maximum water solubility & Minimum penetration

- Applications :• set and dried without rinse• (2 types) shampooed hair & comb or spray & comb (more even)

→ Shampooed out with a single shampooing

Chap4- 70

Cosmetics : hair dyesTemporary Non-oxidative hair dyeing : liquid formulation

(Conditioning agent)

(surfactant)

(acid)

(Thickening agent)

(Alcohol)

Primary alcohol containingC9-C11, HLB = 8.1, MW 270

①

①

②

③

④②

③

④

⑤

⑤ · 3H2O

Chap4- 71

Cosmetics : hair dyesTemporary Non-oxidative hair dyeing : powder / rinse solution / hair crayons

Powder dyes

Rinse solution

Hair cryaons

Chap4- 72


CI Acid Yellow 23(azopyrazol)

CI Acid Yellow 1(nitro)

FD&C Yellow No. 6(azonaphthol)

Chap4- 73


CI Acid Red 33(monoazo)

CI Acid Red 92(xanthene)

CI Acid Orange 24(Monoazo)

CI Acid Orange 7(azonaphthol)

Chap4- 74


CI Acid Violet 43D&C Violet No. 2(anthraquinone)

CI Acid Blue 9(triphenylmethane)

CI Acid Black 1(disazo)

NN

SO3Na

HO

OHN N

H3C

CH3

D&C Brown No. 1(disazo)

Chap4- 75


- Frequently, 2~5 substances are necessary to reach the desired hair color because just one substance does not achieve natural shades.

- Some formulations use two molecules to remove the yellowish effect in white hair and also 4~5 substances are mixed to reach the red, brown, and black shades.

- The temporary non-oxidative formulations as single applications, present higher dye concentrations, ranging from 0.1% to 2.0% (w/w) and have the purpose of promoting a stronger dyeing effect.

- However, this type of application will not cover gray hair satisfactorily in people with more than 30% of white hair fibers.

- The formulation must get in contact with hair for about 30 min and results will occur immediately. It is suitable for those who wish for fantasy colors.

- It resists from 3~6 washes when applied to bleached hair, like semipermanent dyeing.

Chap4- 76


- does not alter the structure of the hair and its natural color.

- gives temporary color for clients who do not want permanent color

- Quick and easy to apply, washes out easily

- Enhance & add brighter tones to dull, mousey hair.

- Blends in a certain amount of gray with natural shades.

- Neutralizes any unwanted tones in the hair.

- Correct faded color until the client arranges for a more permanent solution.

Advantages

Chap4- 77


- Must be reapplied after every shampoo.

- Color results may be uneven, especially if enough rinse is not applied.

- Color will run with moisture or perspiration, rub off on pillow and clothing

- Flake off when the hair is brushed or combed.

- Damaged hair will cause temporary color to penetrate the cuticle and uneven color will be evident.

- Deposit only, they cannot lift or lighten color.

- Often hair is dull and lacks sheen.

Disadvantages

Chap4- 78

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing - These formulations contain colorants with low molar mass such as

► nitroanilines or anthraquinone derivatives► basic(cationic) dyes ► or their mixtureswhich has a high affinity for hair keratin and resists from 3~6 washes.

- Color molecules are larger than those of permanent hair color molecules- Only a small amount of color gets to the cortex, depending on the amount

of peroxide or ammonia in the hair color- Most of the color stays on the cuticle and cannot penetrate inside

Chap4- 79

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : nitroanilines

- Combination of up to 18 dyes : all highly polar ingredients → weak dye-hair interactions (van der Waals forces)

NO2

NH2NH2

NH2

HNNO2

C2H4OH

HNNO2

C2H4OH HN HN

C2H4OH

O2N

C2H4OH

2-Nitro-p-phenylenediamine 4-Nitro-o-phenylenediamine(yellow~orange)

HC Red No.3

HC Yellow No.2 HC Yellow No.4 HC Blue No.1

Chap4- 80

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : nitroanilines, AQs

- Larger dye molecules rinse more slowly due to greater affinity for hair

HC Red No.1 HC Orange No.1

Disperse Black 9

Acid Orange 3

Disperse Violet 1 Disperse Blue 1

Chap4- 81

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : basic dyes

- They permit reflective effects and are excellent for instantaneous color effects.

- The similarities between the size of the cationic molecules grant substantivity to the hair in a homogenous way, ensuring the color reproducibility and the resistance to washing uniformly.

- Cationic dyes exhibit excellent affinity for damaged hair, because positive sites of the dye molecule bind to negative sites on the hair fiber by an ionic bond.

- They allow greater resistance to washing when compared to nitro anilines.

Chap4- 82


CI Basic Red 76CI Basic Red 51

CI Basic Yellow 57

Chap4- 83


CI Basic Brown 17CI Basic Brown 16

CI Basic Blue 99

Chap4- 84


- The cationic dyes are water-soluble; however, they also require the addition of solvents to ensure the homogeneity of the color and prevent recrystallization during storage because, in recrystallized form, the molecule does not provide the cationic sites to bind to hair strands.

- The pH control is essential for color stability: a weak base such as mono ethanolamine must be added to achieve a pH of 9.0, and then a weak acid such as 10% citric solution is used to lower the pH value to 6.0. This way, a buffer system which ensures the pH maintenance of the finished product during shelf life is formed.

Chap4- 85

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : basic dyes + nitroanilines

- Another option of formulation involves mixing nitro aniline dyes with basic or acid dyes which aim for a better color result and a bigger resistance to washes, considering the high affinity of the two families of dyes.

- The hair space not filled with the basic dyes will be occupied by nitro anilines, thus promoting a much more uniform color in the first application.

- The nitro anilines are molecules comprised of a neutral aromatic amine or anthraquinone derivatives and all are classified as highly polar and present mono, di, or tri nuclear rings.

- These dyes are diffused through the hair fiber and are retained by weak Van der Waals bonds.

- Under similar conditions, the larger molecules with tri aromatic rings are removed more slowly from hair than the smaller, mononuclear ones.

Mixing nitroanilines

Chap4- 86


N, N’-bis-(2-hydroxyethyl)-2-nitrophenylenediamine

HC Yellow No. 2 HC Red No. 3

4-hydroxypropylamino-3-nitrophenol


Semi-permanent non-oxidative hair dyeing : basic dyes + nitroanilines

Chap4- 87


- In general, the nitro anilines are not soluble in water and require a glycol or glycol derivative, such as glycerin, to be solubilized in the formulation.

- Specific solvents, such as mixtures of quaternary salts of high molecular weight, such as Quaternium-80, benzyl alcohol, and glycols are used to ensure not only their solubility in the formulation but also during application and product storage.

HC Blue No. 2


Semi-permanent non-oxidative hair dyeing : basic dyes + nitroanilines

Chap4- 88

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing

Formulation

- Dissolve the dyestuff in a mixture of the alkyloamides & anionic surfactant.

- Separately dissolve acid & quaternary ammonium compound in the water and add color to solution while stirring

Chap4- 89


- The application is simple and lasts from 10 to 40 min, followed by rinsing.

- Several products are available in the market: lotions, shampoos, mousses and emulsions. These cosmetic forms must have the ideal viscosity so that they do not flow during the application.

- Dyes with low molar mass penetrate slightly in the cortex, especially because of the high pH value of the product that promotes the cuticles opening.

Chap4- 90

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : vegetable dyes

- Henna is the most widely used vegetable dye for hair, promoting yellow(nonionized form) to reddish orange(ionized form) color shades.

- It consists of the dried leaves of the Lawsonia alba plant, growing in North Africa, in the Midwest, and in India.

- Extracted with aqueous sodium bicarbonate

- In some commercial products, it is mixed with other dyes to increase the range of color.

- Its coloring properties are due to the presence of the substance 2-hydroxy-1,4-naphthoquinone, soluble in hot water and substantive to hair keratin in pH 5.5.: ex. Hair(protonated) + lawsone(anions) + acidic pH

Lawsone, an active compound in Henna

Chap4- 91

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : vegetable dyes

- Another vegetable dye commonly used to obtain yellow shades is chamomile that promotes greater light reflection.

- Of all the species of chamomile, only Anthemis nobilis (Roman Chamomile) and Matricaria chamomillae (German chamomile) have cosmetic applications, and both are substantive to hair.

- The active ingredient of the flowers is 4’,5,7-trihydroxyflavone, also known as apigenin. : yellow mordanted with Cr, Ti or Fe salts.

4’,5,7-Trihydroxy flavone

Chap4- 92

Cosmetics : hair dyesSemi-permanent non-oxidative hair dyeing : metallic dyes

- Metal salts : Lead, silver, bismuth, cobalt, copper, iron, mercury

ex. Lead dyes : contain lead acetate and sulfur which form Pb-S complex in cuticles → darken slowlyshades are limited & dye can react with certain other

- Another form of metallic dye : premetalized dyescomplexes of acid dyes with Cr, Co, or other metals.

ex. 1:2(metal:dye) metal complex dyes

Chap4- 93


- Structure of the hair is not affected : Little or no damage

- Blending gray hair

- More permanent methods of hair coloring enhance natural hair color by adding tone & depth.

- Formulated as toners for pre-lightened hair.

- Safer to use on clients who are pregnant or sensitive/allergic to PPD.

Advantages

Chap4- 94


- Limited shades of the older formulas

- Color is not long lasting, needs repeated applications depending on frequency of shampoos.

- Porosity of hair will effect how soon it fades, and off-shades after several shampoos.

- Rarely provides sufficient coverage on gray hair.

- Cannot lift hair color : enhances original color or darkens only

Disadvantages

Chap4- 95

Cosmetics : hair dyesDemi-permanent non-oxidative hair dyeing :

- Demipermanent hair products promote major hair color durability(resistance up to 20 washes) because they consist of a mix of semipermanent molecules with oxidation dye precursors, applied with hydrogen peroxide (H2O2).

- These are chemically milder than permanent hair colorants: less stronger chemicals(ex. ethanolamine) and a lower concentration of hydrogen peroxide.

- The color is developed and deposited similar to permanent hair colors but hair's natural pigment is not removed.

Chap4- 96

Cosmetics : hair dyesDemi-permanent non-oxidative hair dyeing :

- No lifting (removal) of natural hair color

- The final color is more natural looking

- Safer, especially for damaged hair,

- Wash out over time (typically over 20 shampoos), so root regrowth is less noticeable

- If a change of color is desired, it is easier to achieve.

Advantages over permanent color

Chap4- 97

Cosmetics : hair dyesOther dyes for hair : natural-based oxidative hair coloring

ex. Oxidation of DOPA to dopaquinonewhich reacts with cysteine(nucleophile) to form the natural red

potassium ferricyanide

- Oxidantant such as atmospheric oxygen work, although the combination of H2O2and I- appears to be more effective

- Intense black eumelanin-type pigment by reacting DOPA with controlled amounts of potassium ferricyanide.

- By beginning with the oxidation of DOPA and incorporating sulfur-containing nucleophiles in the process, a wide range of shades can be produced.

3,4-dihydroxyphenylalanine (DOPA)

DOPA

Chap4- 98

Cosmetics : hair dyesOther dyes for hair : fiber reactive dyes

- Binds to the hair or wool(keratin) through covalent bondsNucleophilic substitution reaction : chlorotriazine typeNucleophilic addition : vinylsulfone typeNucleophilic substitution and addition : α-bromoacrylamide type

- Has not been used commercially for human dyeing- Prior reduction of mercapton groups can enhance dyeability

NN

NN

NHR

ClH

R Hair NH2

NN

NN

NHR

NHH

R

Hair

+ HCl

Chlorotriazine (monochlorotriazine, MCT)

Vinylsulfone

α-bromoacrylamide

Chap4- 99

Cosmetics : hair dyesIdeal characteristics of hair dyes

- Non-toxic & non-irritant to skin/hairs

- Impart same color which indicate on its label

- Easy to apply

- Have reasonable stability of shelf life

- Not dermatitis sensitizer

- The color that imparts to the hair must be stable to air, light, water & shampoo.

Chap4-

Properties Measurement

viscosity, hardness, stability

Viscosity for shampoo type, hardness for cream type after conditioning at 30℃ for 24 hours

pH pH measurement of 10% diluted solution

Drop movement Measure the running distance after dropping the Mixture of phase 1 and 2 on an inclined(67.5˚) surface

Color difference CIE L*, a*, b* and Δ E by using a color measurement instrument

Dye penetration Microscopic observation of cross-section of dyed human hair

Stability of oxidizing agent

Titration of hydrogen peroxide after treatment in water bath at 100℃ for 48hours → reduction of less than 4%

100

Cosmetics : hair dyesCheck points of hair dyes

Chap4-

Tests method

Chemical damage measurement

Quantitative analysis of Cationic fluorescent dye stained on the sulfonic acid which was formed after dyeing (by using HPTLC)

Physical damage measurement

Friction Test

Shampoo Test Color change measurements after shaking in shampoo solution for 3min (5 times repeat)

Ultraviolet Test Fadeometer test

101

Cosmetics : hair dyesCheck points after dyeing

Chap4- 102

Pharmaceutical applications

Chap4-

► Increase aesthetic appearance► For identification► Insoluble colors or pigment contributes to the stability of light► The psychological effects of color

- Red area, warm colors = warmth, comfort/anger hostility- Blue area, cool colors = calm / sadness

103

Colorants purpose in pharmaceutical preparation


Chap4-

- Nontoxic & no physiological activity & free from harmful Impurities- Stable on storage : Unaffected by light, temp., hydrolysis and

micro‐organisms- Compatible with medicaments and not interfere with them - High coloring power (tinctorial strength) : use small quantities- Assay is practicable and easier- Should not be appreciably adsorbed on to suspended matter- Ready solubility in water but some oil‐soluble and spirit‐soluble

colors are necessary- Free from objectionable taste and odor- Readily available and inexpensive

104

Ideal properties of colorants


Chap4-

A. Organic dyes and their *lakes

B. Inorganic colors or mineral colors

C. Natural colors or vegetable and animal colors

105

Classification


*Lakes have been defined by the FDA as the "Aluminum salts of FD&C water soluble dyes extended on a substratum of alumina".→ Lakes are formed by the precipitation and absorption of a dye on an insoluble base or substrate.

Chap4-

Dyes Lakes▶ Are insoluble and color by dispersion.▶ Particle size of lakes is very critical to

their coloring capacity : smaller the particle size, the higher the tinctorialstrength due to increased surface area for reflected light.

▶ Insoluble enables the drying stages to be performed more quickly.

▶ The opacity of the system minimizes the defect of tablet surface depressions

▶ Good color reproducibility

▶ Coloring power exhibit when dissolved in a solvent.

▶ The physical properties of dyes (particle size etc) are usually not proportional to coloring power.

▶ The tinctorial strength of a dye is directly proportional to its pure dye content.

▶ Soluble in propylene glycol and glycerin.

▶ Wider range of shades or hues with higher coloring power.▶ Cheap.

106

Organic dyes and their lakes


Chap4-

▶ Stability towards light

▶ Some of them have useful opacifying capacity (e.g. TiO2)

→ to color and opacify hard gelatin capsules

▶ Wide regulatory acceptance : most useful for multinational

companies wishing to standardize international formulae.

▶ Limited range of colors

▶ Many mineral colors have toxic effects and have been

replaced by synthetic dyes

107

Inorganic colors or mineral colors


Chap4-

▶ Extraction from a natural source

▶ A wide acceptability

▶ Low stability to light

▶ Variation in coloring power and difficulty of standardization

▶ The tinctorial power is very low and fugitive in solution

▶ Less readily available and more expensive

108

Natural colors or vegetable and animal colors


Chap4-

▶ The only three left in the codex are caramel, cochineal and carmine.

▶ Caramel : formerly called burnt sugar, prepared by heating water‐soluble carbohydrates with an accelerator until a black viscid mass is formed

▶ Cochineal : a dried insect▶ Carmine : the aluminum lake of the coloring matter of

cochineal.

109



Chap4-

▶ Caramel color is one of the oldest and most widely used food colorings

▶ widely approved for use in food globally but application and use level restrictions vary by country.

▶ found in many foods and beverages including :

batters, beer, brown bread, buns, chocolate, cookies, cough drops, spirits and liquor such as brandy, rum, and whisky, chocolate-flavored confectionery and coatings, custards, decorations, fillings and toppings, potato chips, dessert mixes, doughnuts, fish and shellfish spreads, frozen desserts, fruit preserves, glucose tablets, gravy, ice cream, pickles, sauces and dressings, soft drinks (especially colas), sweets, vinegar, and more. 110

Natural colors or vegetable and animal colors : caramel color


Chap4-

▶ Other examples for natural colorants include Riboflavin and Anthocyanins, Paprika Oleoresin, Annatto, Beet Root Red, Curcumin [Turmeric].

111



Capsaicin

Riboflavin(Vitamin B2)

AnthocyaninsChap4-

▶ Other examples for natural colorants include Riboflavin and Anthocyanins, Paprika Oleoresin, Annatto, Beet Root Red, Curcumin [Turmeric].

112



Betanin

BixinCurcumin

Chap4- 113

Physical and chemical properties


Chap4-

▶ FD&C colors : colorants that are certifiable for use in foods, drugs, and cosmetics

▶ D&C colors : dyes and pigments considered safe in drugs and cosmetics when in contact with mucous membranes or when ingested.

▶ External D&C colors : colorants, due to their oral toxicity, are not certifiable for use in products intended for ingestion but are considered safe for use in products applied externally

114

The food, drug, and cosmetic act


Chap4-

▶ Codes for substances that can be used as food additives for use within the European Union and Switzerland.

▶ The "E" stands for "Europe". They are commonly found on throughout the European Union.

▶ Safety assessment and approval are the responsibility of the European Food Safety Authority.

▶ E100-199 (Colors), E200-299(Preservatives), E300-399(antioxidants, acidity regulators), E400-499(thickeners, stabilizers, emulsifiers), E500-599(acidity regulators, anti-caking agents), E600-699(flavor enhancers), E700-799(antibiotics), E900-999(glazing agents and sweeteners), E1000-1599(additional chemicals)

115

E numbers


Chap4-

▶ FD&C Yellow 5, E102, CI 19140▶ Yellow or orange yellow powder▶ Aqueous solutions are yellow▶ Monoazo pyrazolone dye▶ used to improve the appearance of a product and to impart a

distinctive coloring for identification purposes.▶ US regulation require that prescription drugs for human use

containing tetrazine bear the warning statement : “This product contains FD&C yellow #5 (Tartrazine) which may

cause allergic‐type reactions (including bronchial asthma) in certain susceptible persons.”

116

Tartrazine


Chap4-

▶ FD&C Yellow 6, CI 15985, E110▶ Reddish yellow powder, and aqueous solutions are bright orange▶ Monoazo dye▶ Often used in conjunction with E123, Amaranth, in order to

produce a brown coloring in both chocolates and caramel.

117

Sunset Yellow FCF


Sunset Yellow FCF, E110 Amaranth, E123

Chap4-

▶ FD&C Yellow 11, Solvent Yellow 33, CI 47000▶ Bright yellow dye with green shade ▶ insoluble in water, but soluble in non polar organic solvents▶ used in spirit lacquers, polystyrene, polycarbonates,

polyamides, acrylic resins, and to color hydrocarbon solvents.

▶ Also used in externally applied drugs and cosmetics

118

Quinoline Yellow SS


Chap4-

▶ FD&C Blue 1, Eriosky Blue, E133, CI 42090, ▶ Can be combined with Tartrazine (E102) to produce various shades

of green.▶ Widely used in saps, shampoos, mouth washes, and other hygiene

and cosmetics applications.▶ May induce an allergic reaction in individuals with preexisting &

moderate asthma

119

Brilliant Blue FCF


Chap4-

▶ FD&C Blue 2, E132, CI 73015 ▶ Dark blue powder and aqueous solutions are blue or bluish

purple ▶ Primary use is as a pH indicator▶ Used with yellow colors to produce green colors.▶ Used as a dye in the manufacturing of capsules

120

Indigo carmine


Chap4-

▶ pure state as red crystals : varying from pale yellow to dark orange▶ used as a color for sugar‐coated tablets▶ very unstable to light and air : should be securely packaged▶ particularly unstable when used in spray‐coating processes, probably

owing to atmospheric oxygen attacking the finely dispersed spray droplets.

▶ Because of its poor water solubility, β‐carotene cannot be used to color clear aqueous systems, and cosolvents such as ethanol must be used.

▶ Suppositories have been successfully colored with β-carotene in approximately 0.1% concentration

121

β-carotene

Pharmaceutical applicationsCI 75130(natural) 40800(synthetic), E160a

Chap4- 122

disodium salt of 2,4,5,7-tetraiodofluorescein

▶ FD&C Red 3, E127, CI 45430▶ Organoiodine compound, a derivative of fluorone.▶ The lake of erythrosine has been delisted in the USA since

1990, following studies in rats that suggested that it was carcinogenic.

▶ However, erythrosine was not regarded as being an immediate hazard to health: chronic ingestion can cause cancer

Erythrosine


Chap4-

▶ Dark red powder approved by the US FDA for use in cosmetics, drugs, and food.

▶ May have slightly less allergy or intolerance reaction but people with skin sensitivities should be careful

▶ Not recommended for consumption by children : cancer in mice

▶ It is banned in Denmark, Belgium, France, Germany, Switzerland, Sweden, Austria and Norway.

123

Allura Red AC


▶ FD&C Red 40, Food Red 17, E129,, CI 16035

Chap4- 124


Chap4- 125

Triarylmethane

Fast Green FCF


▶ FD&C Green 3, Food Green 3, E143, CI 42053▶ Triarylmethane structure▶ Its use as a food dye is prohibited in EU and some other

countries▶ is the least used of the seven main FDA approved dyes in USA

Chap4-

▶ D&C Green 6, Solvent Green 3, CI 61565▶ green dye, an antrhaquinone derivative.▶ Appearance of a black powder with m.p. of 220~221˚C. ▶ Insoluble in water▶ Used for adding greenish coloring to materials : cosmetics and

medications

126

Quinizarin Green SS


Chap4-

▶ Pigment White 6, CI 77891, E171▶ an effective opacifier in powder form, where it is employed as a

pigment to provide whiteness and opacity to products ▶ Applications : paints, coatings, plastics, papers, inks, foods,

toothpastes and medicines (i.e. pills, tablets and also in topical pharmaceutical formulations)

127

Titanium dioxide


Chap4-

▶ Pharmaceutical applications : Iron oxide black, Iron(III) oxide hydrated, Iron oxide red, and iron oxide yellow monohydrate

▶ The color depends on the particle size and shape, and the amount of combined water

▶ UV absorbers ▶ Becoming of increasing importance as inorganic colorants▶ Have restrictions in some countries on the quantities

128

Iron oxide black Iron oxide red Iron oxide yellow monohydrate

Iron oxides


Chap4- 129

Tablets Tablet coating Capsules Liquid

productsOintments& salves

Tooth pastes

→ Colorant is to be incorporated.

→ Should meet as many characteristics as the ideal colorant.

Coloring systems for dosage forms


Chap4-

Common approach to coloring a tablet formulating Dissolving water‐soluble dyes in a binding solution Disadvantages

– during drying of the granulation, the soluble colors migrate

– more than one color, the dyes may migrate at different rates

– ⇒ have a mottled appearance Solutions

– starches, clays, and talc adsorb the dye– Reducing the migration (not eliminating)– by using lakes or other pigments (∵ insoluble)– ⇒ light stability of the product will be improved

130

Tablets – Wet granulation


Chap4-

economic reason The number of processing steps reduced, requires blending

only lakes and other pigments are used (elimination of the wetting

step) Disadvantage

– poor blending->color specking and “hot spots.” Solutions

– can be minimized by pre‐blending the pigment– with other small ingredients before addition to the entire

mixture ⇒reduce pigment particle agglomeration

131

Tablets – Direct compression


Chap4-

Patented by Arnold Nicholson and Stanley tucke Very time‐consuming and delicate operation. Before the 1950s, traditional color coating used soluble dyes as the prime

colorant. Can produce the most elegant tablet but, dye being soluble. Color migration readily occurs the drying stage not handled properly

⇒non-uniform distribution of color or mottling Small depressions or irregularities in the surface

⇒ non‐Uniform color Many smoothing coats are needed before any color can be applied. Need to care - do not become over colored. Syrups

– Increasing dye concentrations are used to control mottling.– Essentially an aluminum lake and a pacifier dispersed in a syrup

solution. – Produced brightly colored, elegant tablets – Eliminated many of the problems about sugar‐coating techniques.

132

Tablets coating – sugar coating


Chap4-

Sugar coating is a multistage process and can be divided into the following steps:

1. Sealing of the tablet cores-against water2. Subcoating-to attain rounded sugar coated tablet3. Smoothing- sucrose syrup4. Coloring- Nearly all sugar-coated tablets are colored5. Polishing- to acquire an acceptable appearance6. Printing - To facilitate identification

133

Tablets coating – sugar coating


Chap4-

Application of a film‐forming polymer onto the surface of substrate Polymers also contains plasticizers and colorants-to achieve the

desired properties• ⇒The polymer and the plasticizer dissolved in a solvent ->to form a

coating solution ->the colorants can be dissolved or dispersed. (used organic solvents for polymer solution)

Today, aqueous systems for environmental reasons (replaced the organic solvent) Disadvantage

• Color migration on drying of the films• relatively thin-> small differences in film thickness ->color variation.

Success in using pacified dye systems; But, poorer light stability

The colorants - lakes and inorganic pigments.⇒reduce moisture diffusion through film and improve light stability

134

Tablets coating – film coating


Chap4- 135



Chap4- 136

Ideal characteristics of a film coating polymer

Solubility : good solubility in aqueous fluids Viscosity : low viscosity for given concentration->permit

east trouble free spraying Permeability : to optimize the shelf-life of a tablet

preparation, some polymers are efficient barriers against the permeability of water vapor or other atmospheric gases

Mechanical properties : sufficient coating strength-prevent cracks



Chap4-

Hydroxypropyl methylcellulose Methylcellulose and hydroxypropyl cellulose Methacrylate amino ester copolymers

137

Hydroxypropylmethylcellulose

methylcellulose and hydroxypropylcellulose

Methacrylate amino ester copolymers

Tablets coating – film coating: film forming polymers


Chap4-

to modify the physical properties of the polymer ⇒ One important property is their ability to decrease film brittleness.

In general, only water-miscible plasticizers can be used for aqueous-based spray systems.

Examples of plasticizers are:– polyols, such as polyethylene glycol 400– organic esters, such as diethyl phthalate– oils/glycerides, such as fractionated coconut oil.

138

Tablets coating – film coating: plasticizer


Chap4-

water-insoluble colors (pigments).

Pigments have certain advantages over water-soluble colours:– they tend to be more chemically stable towards light,– provide better opacity and covering power,– optimize the impermeability of a given film to water vapor.

Examples of colorants are:– iron oxide pigments– titanium dioxide– aluminium Lakes.

139

Tablets coating – film coating: colorants


Chap4- 140

Sugar coating vs film coating


Chap4-

capsules are colored primarily using FD&C or D&C colorants(sometimes an opacifying agent such as Titanium dioxide)

colored using water‐soluble dyes -> solution of these colors is simply added to the gelatin melt

The pH can alter the shade of the color. It is also important to control the tackiness of the capsule wall

because variations can change color intensity. If the active ingredient is photosensitive->opaque

capsule.(contain pigments or dyes and an opacifier) spin printing : color identify capsules through the use of colored

imprinting inks.

141

Capsules : hard gelatin capsules


Chap4-

one piece, hermetically sealed, soft gelatin shells containing a liquid, a suspension, or a semisolid

Color used in shell has to be darker

Opacifier, usually Titanium dioxide, may be added to produce an opaque shell, to prevent photo degradation of light sensitive fill ingredients.

142

Capsules : soft gelatin capsules or soft gels


Chap4-

Dyes should be completely soluble in the particular solvent & at the required concentration

Dyes that correspond to the flavor will be chosen Factors influencing the shade and stability of dyes in the liquid

system– pH, microbiological activity, light exposure in the final product

package, the compatibility of the dye with other ingredients the lowest possible concentration of dye needed to give the

desired color should be used -> higher concentrations can results in a dull color

Do not added dye directly to the bulk mixing tank->difficult to determine and could cause additional problems

In non‐aqueous systems, (solubility restrictions) the use of pigments is necessary.

If pigments are chosen as the colorants, it may be necessary to predispersed them before adding them to the final product.

143

Liquid products


Chap4-

dyes and pigments can be used

Pigments are preferred because they will not migrate to the surface.

To incorporate the pigments->it may be necessary to blend the pigment and the product on a roll or ointment mill

144

Ointments and salves


Chap4-

A major problem impacting the aesthetic appearance of striped toothpaste is the bleeding or migration of color from one component into another. This is especially severe if one colored component is applied to the surface of a white base. For this reason, a colorant that exhibits substantially no visible bleeding is required.

The high density polyethylene entrained colorants of the present invention unexpectedly are substantially non‐bleeding when present in conventional toothpaste or gel formations, particularly when contrasted with similar colorants entrained in wax and synthetic polymeric resins including paraffin wax and low density polyethylene. For example, the colorant may be entrained in the High Density Polyethylene" (HDPE) matrix using methods of encapsulation.

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Tooth pastes


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The permitted colors most popular tints and shades can be obtained by blending.

Color combinations can attract or distract. So, while blending the colorants to produce different shades ⇒ require knowledge about the individual colorant

The National Formulary of the United States gives information on the proportion of various water soluble and oil soluble dyes⇒(to give particular hues to liquid preparations and drug powders)

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Blending of colorants


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1. Oxidizing agents, reducing agents2. Microorganism3. Extreme pH levels (should not be used below pH 5.0)4. Minimize the exposure of products to direct sunlight,

especially products containing dye blends

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Colorants should be protected during processing, use and storage, against


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Lakes, inorganic dyes, and synthetic dyes – should be stored in well‐closed & light‐resistant containers at a temperature below 30°C.

natural and nature‐dentical colors - storage conditions are important to extend shelf life → sealed in containers ungerNitrogen

To compensate for losses during processing and storage, some formulators add a slight excess of dye at the beginning.– This approach should be cautiously employed since one

can obtain unattractive shades when too much color is added at the beginning

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Stability and storage conditions


Cosmetics : hair dyes Chap. 4. Food, Drug &...

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