Shampoos

Introduction : 

Definition: A shampoo is a preparation of a surfactant (i.e. surface active material) in a suitable form – liquid, solid or powder – which when used under the specified conditions will remove surface grease, dirt, and skin debris from the hair shaft and scalp without adversely affecting the user.

Requirements of a Shampoo:

•  It should effectively and completely remove dust or soil, excessive sebum or other fatty substances and loose corneal cells from the hair.
•  It should produce a good amount of foam to satisfy the psychological requirements of the user
• It should be easily removed on rinsing with water.
•  It should leave the hair non-dry, soft, lustrous with good manageability and minimum fly away.
•   It should impart a pleasant fragnance to the hair.
•  It should not cause any side-effects / irritation to skin or eye. It should not make the hand rough and chapped.

Types of Shampoo : 

• ·         Powder Shampoo
• ·         Liquid Shampoo
• ·         Lotion Shampoo
• ·         Cream Shampoo
• ·         Jelly Shampoo
• ·         Aerosol Shampoo
• ·         Specialized Shampoo
• ·         Conditioning Shampoo
• ·         Anti- dandruff Shampoo
• ·         Baby Shampoo
• ·         Two Layer Shampoo

PRODUCT INGREDIENTS : 

Surfactants are the main component of shampoo. Mainly anionic surfactants are used.

The raw materials used in the manufacture of shampoos are:

Principal surfactants: Provide detergency and foam.

Secondary surfactants: Improve detergency, foam and hair condition.

Other additives. CLEANSING ACTION OF SHAMPOO A surfactant consists of two part- one hydrophilic (water loving) while the other is hydrophobic in nature.

Surfactants : 

Surfactants Anionic surfactants are mostly used (good foaming properties). The hydrophilic portion carries a negative charge which results in superior foaming, cleaning and end result attributes. Non-ionic surfactants have good cleansing properties but do not have sufficient foaming power. Cationic surfactants are toxic and are hence not used. However, they may be used in low concentration in hair conditioners. Ampholytics, being expensive, are generally not used. However, they are mainly used as secondary surfactants and good hair conditioners.

ADDITIVES : 

Conditioning agents: Lanolin, mineral oil, herbal extracts, egg derivatives.

Foam builders: Lauroyl monoethanolamide, sarcosinates

Viscosity modifiers : Electrolytes – NH4Cl, NaCl Natural gums – Gum Karaya, tragacanth, alginates Cellulose derivatives – Hydroxy ethyl cellulose, methyl cellulose Carboxy vinyl polymers – Carbopol 934 Others – PVP, phosphate esters.

Sequestering agents: EDTA

Opacifying agents: Alkanolamides of higher fatty acids, propylene glycol, Mg, Ca and Zn salts of stearic acid, spermaceti, etc.

Clarifying agents: Solubilizing alcohols – ethanol, isopropanol Phosphates – Non-ionic solubilizers – polyethoxyated alcohols and esters.

Perfumes : Herbal, fruity or floral fragnances.

Preservatives : Methyl and propyl paraben, formaldehyde (most effective).

Anti-dandruff agents: The shampoos contain small amount of these actives, which are in contact with the scalp for only a short time. In order to be effective the active ingredient must work in the oil-water environment of the scalp and must be readily substantive to the scalp for continuing activity.

Eg: Selenium sulfide, zinc pyrithone, salicylic acid.

Evaluation of Shampoos : 

• ·         Evaluation of Shampoos Performance characteristics
• ·         Foam and foam stability
• ·         Detergency and cleaning action
• ·         Effect of water hardness
• ·         Surface Tension and wetting
• ·         Surfactant content and analysis
• ·         Rinsing Conditioning action Softness Luster Lubricity Body, texture and set retention
• ·         Irritation and toxicity
• ·         Dandruff control
• ·         Microbiological assay
• ·         Eye irritancy test
• ·         Product characteristics
• ·         Fragnance
• ·         Colour
• ·         Consistency
• ·         Package

1.Foam and foam stability: The Ross-Miles foam column test is accepted. 200 ml of surfactant solution is dropped into a glass column containing 50ml of the same solution. The height of the foam generated is measured immediately and again after a specified time interval, and is considered proportional to the volume. Barnett and Powers developed a latherometer to measure the effect of variables such as water hardness, type of soil and quantity of soil on foam speed, volume and stability. Fredell and Read titrated actual standard oiled heads of hair with additive increments of shampoo until a persistent lather end point appeared.

2.Detergency and cleaning action: Cleansing power is evaluated by the method of Barnet and Powers 5gm sample of soiled human hair is placed at 35°c in 200 cc of water containing of 1 gm of shampoo. The flask is shaken 50 times a minute for 4 minutes. Then washed once again with sufficient amount of water, then after filter the hair dried and weighed. The amount of soil is removed under these condition is calculated.

3. Wetting Action: Canvas disk sinking test: A mount veron cotton duck # 6 canvas disk 1 inch in diameter, is floated on the surface of a solution, and the time required for it to sink is measured accurately.

 4. Rinsing: Skilled beauticians are employed to make comparisons on the performance of several shampoos.

5. Conditioning Action: Conditioning action is a difficult property to assess. This is because it is basically dependent on subjective appraisal. No method has been published for measuring conditioning action. The degree of conditioning given to hair is ultimately judged by shampoo user who is making the evaluation on the basis of past experience and present expectations.

6. Microbiological assay: PREPARATION OF PRE-INOCULUM Take the loopful culture of staphylococcus aureus (ATCC6532) aseptically and transfer to sterilized and cooled 100 ml SCDM (broth). Mix well. Incubate the broth at 37oC for 24 hrs. PREPARATION OF MEDIA Soya bean casein digests medium, soya bean casein digest agar and nutrient agar. PREPARATION OF POUR PLATES Sterilized SCD agar (100 ml) is cooled to 40°C and mixed with 5 ml of 24 hrs old pre inoculated culture. This is immediately poured in plates (340 ml each) and allows to set. MAKING THE WELLS ON AGAR PLATES The wells are dig on agar plates with sterilised well digger aseptically. Take 100µml of each sample, add to well aseptically. Incubate the plates at 37oC for 24 hrs to 48 hrs. Observe the effectiveness of sample on culture growing on the agar plate and we can see the effectiveness of sample in the form of zone of inhibition around each well containing different sample.

7. Evaluation of eye irritancy: The test calls for dropping 0.1 ml of liquid shampoo in the conjunctiva sac of one eye of the rabbit , the other eye serving as control. In the case of the first three animals, the treated eye remains unwashed. Since washing the eye may or may not alleviate symptoms of injury. The six remaining animals are divided into two equal groups. In the first of these groups eyes instilled with the substances are washed with 20 ml of lukewarm water two seconds after treatment and in the second group after instillation. Readings are then made at 24, 48 and 72 hr and again four and seven days after treatment. If the lesions have not cleared up in seven days the test material is considered as severe irritant.

8. Viscosity: Viscosity of the liquid shampoo is determined using a Brookefield viscometer 100 mL of the shampoo is taken in a beaker and the spindle is dipped in it for about 5 min and then the reading is taken.

9.Oral toxicity  

1.        Oral toxicity can be given in terms of its lethal dose 50 ( LD/50 ) i.e., number if gms of the material per kg of body weight required to kill half of the test animals used.

2.       Fasting cage animals are taken & dosing is accomplished with the help of stomach tube.

3.       Lower the LD/50 the greater the toxicity

10.Test for pH

1.      Soap based shampoos are more effective in pH of 9.0-10.0.

2.       Synthetic detergent based shampoos are effective pH range of 6.0-9.0.

3.       pH can be measured with the help of pH meter

11.Skin irritation tests

Draize Test in rabbits

·         A set of 6 rabbits is used for testing each material.

·         Shampoos should be tested only for a short duration, that is, not more than 4 hrs as these products come in contact with the skin only for a short duration.