Thursday, 26 November 2015

Cosmetic notes for GPAT: Formulation of Lipstick, Shampoos, Nail preparation, Dentrifices and creams

Cosmetic section under Pharmaceutics has a good weightage in the GPAT exam preparation. There will be a handy amount of questions come in the GPAT exam every year. In this article we will discuss the formulation of them one by one.

                                  Formulation of Lipstick

Lipstick can be defined as molded stick made up of coloring substances formulated in a blend of fatty bases. Their main purpose is to impart color to the lips and to make them attractive.
Formulation of Lipstick include:
1.  Base: Base is used to achieve to impart desired melting point, viscosity, dissolving of dyes and dispersion of insoluble pigments. Bases used in the lipstick formulation can be further divided as:

a) Waxes: Common wax (Bees wax- 5-20%), Microcrystalline wax (Ozokerite 1-10%, Ceresine-5-20%) and Hard waxes (Caranuba- 1-3%, Hard Paraffin-1-5%).
b) Softening agents:
Petrolatum: For Gloss
Anhydrous lanolin: Softness, Emolience and lip protection
Lanolin (Hydrous wool fat): Dispersion of color
Lecithins: Emolience & ease of application.
c) Oils:
Castor oil: 30-40%
Liquid paraffin: 1-5%
Isopropyl myristate: 2-3%

2. Bromo mixture: It is used where the desired lipstick has high staining property (Tetrabromo fluorescein).

3. Color mixture: Insoluble dyes and lake colors. TiO2 used as opacifying agent (to modify shade of dyes).

4. Antioxidants: Used to prevent rancidity. Propyl gallate, butyl hydroxyl anisole (BHA), butylhydroxy toluene (BHT) and tocopherol.

5. Preservatives: Benzoates, propylparahydroxybenzoate

Evaluation of Lipstick 

Following tests are used for the evaluation of lipstick:
  •      Droop point test: The temperature at which lipstick starts leaking oil or flattens is known as droop point.
  •      Breaking point test: This test is employed for assessing the strength of the lipstick. Lipstick is held horizontally and weight is applied. The weight at which it breaks is termed as breaking point of the lipstick.
  •        Test for penetrability: Indicates the rheological property of the lipstick. A needle of specific diameter is allowed to penetrate the lipstick and depth of penetration is noted.
  •        Test for force of application: Lipstick is applied on the piece of paper at an angle of 450 and the force required for applying is read from the balance.
  •      Stability test: Stability of lipstick can be determined by means of accelerated stability test.

Formulation related problems in lipstick:

  •       Sweating: Increased oil content.
  •       Bleeding: Separation of coloured liquid.
  •       Blooming: Surface appeared dull (Increased amount of cetyl alcohol)
  •       Streaking: Thin lines or band of colours due to floatation of oil particles in TiO2.
  •       Seams: Marks left on the lipstick when split moulds are used.

Formulations of Shampoos

Shampoo is a preparation used for the purpose of cleansing hair and to impart lustre to the hairs. Its formulation can be studied under the following headings:

1. Surfactants: Anionic surfactants are chief surfactants used in the formulation of shampoos. Cationic ones can be used only in conditioners as they have high irritating property. Non-ionic surfactants have poor foaming potential. Soaps were used earlier but discontinued due to high alkaline nature which makes hair dull.

Common surfactants used are sodium lauryl sulphate, triethanolamine lauryl sulphate and monoethanol lauryl sulphate.

2. Foaming boosters: They are used for improving the quality and stability of the lather (Fatty acid alkanoamides, Amine oxides).

e.g. Lauramide diethylamide , Lauramine oxide, Cocamine oxide.

3. Conditioning agents: These agents are used for enhancing manageability and glow of the hairs.
Various conditioning agents include: Lanolin, mineral oil, egg, albumin, amino acids, lecithin & herbal extracts (Shikakai, henna).
Conditioning agents can also be classified as:
  •      Fat: fatty alcohols, sterols, fatty acids, glycerides.
  •      Silicones: Dimethicone, dimecopolyol
  •      Hydrolysed proteins

4. Special additives:
a) Anti-dandruff agents: Zinc pyridinium thio N-oxide (ZPTO), Selenium sulphide, zinc undecylate, bithinol, resorcinol etc.
b) Acidifying agents: To regain lusture. Citric acid, phosphoric acid, boric acid, lactic acid and glycolic acid.

5. Preservatives: There are various preservatives used for this purpose. Formaldehyde should not be used with protein because it condenses with free amino group.

6. Sequestering agents: Prevent deposition of calcium and magnesium salts on hairs. e.g. EDTA, citric acid etc.

7. Viscosity modifiers: Natural gums like gum karaya, gum tragacanth, Cellulose derivatives ( CMC, HPMC), carbopol, polyvinyl alcohol.

8. Opacifying agents: Sodium Lauryl sulphate, Ethylene glycol stearate, Glycerol monostearate, cetyl & stearyl alcohol, propylene glycols, btylene glycols, glycerine, sorbitol.

9. Stabilisers: BHT, BHA, Tocopherol.

Draze’s test in rabbits is used for the evaluation of shampoo’s eyes irritational potential.

Formulation of nail preparations

Nail preparation is also known as manicure preparations. Various manicure preparations which are in use: Nail bleaches, Nail enamel, enamel removers and nail elongators.

1.  Nail bleaches: Used for removing stains and imparting whiteness to the nails. They generally contain oxidizing/reducing agents like sulphates.
A typical formula for nail bleach include: Hydrogen peroxide (55%), glycerine (15%), citric acid (6%) and water to make 100%.

2. Nail enamels/lacquers: Intended to impart lusture and colour to nails. Formulation of nail lacquers includes:
a) Film formers: Cellulose nitrate (most common), cellulose acetate, cellulose acetobutyrate, ethyl cellulose and methcrylate.

b) Solvents: They are further classified as:
High boiling: Butyl lactate, Ethyl oxalate, isoamyl acetate.
Low boiling: ether, carbon disulphide, acetone, methyl acetate, ethyl acetate.
Medium bioiling: Isopropyl acetate, toluene, isopropyl alcohol, amyl formate.

c) Plasticisers: Impart flexibility and gloss to the film.
Dibutyl phthalate, resorcinol doacetate, castor oil, butyl acetyl ricineolate etc.

d) Pearlescent: Used to provide pearly appearance to the film. 2-amino, 6-oxypurine (crystalline guanine), bismuth oxy chloride coated pigments.

Formulation of dentrifrices

Dentrifrices (tooth powder and tooth pastes) are the products intended to cleanse the teeth of food particles, prevent calculus and plaque formation and to leave a fresh feeling in mouth.

1. Tooth powder: Formulation of tooth powder includes:
a) Abrasive and polishing agents: Calcium carbonate, Dicalcium phosphate, Tricalcium phosphate, sodium metaphosphates.
b) Detergent and foaming agents: Sodium lauryl sulphate, sodium lauryl sarcosinate, diethyl sodium sulphosuccinate, magnesium lauryl sulphate.
c) Sweetening agents: Saccharin sodium.
d) Flavoring agents: Anise oil, peppermint oil, clove oil, cinnamon oil, spearmint oil etc.

2. Tooth paste: Formulation of tooth paste is similar to tooth powder except the following:
a) Humectants: Glycerine, propylene glycol, sorbitol.
b) Binding agents: Gum tragacanth, gum Arabic, karaya gum, sodium alginate, agar veegum, bentonite etc.
c) Preservatives: Methyl Paraben and propyl paraben
d) Anticaries agents: Sodium fluoride, sodium lauryl sarcosinate etc.
e) Antibacterials: Triclosan
f) Desensitizers: Potassium nitrate and strontium chloride.

Formulation of creams

They are emulsions with o/w or w/o type.
Classification of creams: creams are further classified as:
1. Makeup creams
2. Cleansing cream (w/o type) and vanishing creams (o/w type).
3. Winter creams (w/o type)
4. Moisturizing cream
5. All-purpose cream
6. Night creams
7. Skin protective & hand creams

Ingredients of cream: Water, petroleum oil, vegetable oil, fats & waxes derivates, humectants and emulsifying agents.

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5.  Miscellaneous topics for GPAT

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