Book 2-306-323

9.1 INTRODUCTION

• Washing the hair and scalp is a common practice influenced by geographic and economic factors.

• Development of synthetic detergents in the 1930s revolutionized shampoos, making them widely used by the 1950s.

• Modern shampoos must not only cleanse but also leave hair easy to comb, lustrous, manageable, and user-friendly.

9.1.1 Requirements of a Shampoo

1. Remove sebum and atmospheric pollutants from hair and scalp.

2. Eliminate residues from previous hair treatments (e.g., styling products).

3. Provide an optimum level of foam to meet user expectations.

4. Leave hair in a satisfactory condition for easy combing, both wet and dry.

5. Serve as a vehicle to deposit beneficial materials onto hair and scalp.

6. Be non-toxic and non-irritating to hair and scalp.

7. Be non-damaging to eye tissues if contact occurs.

9.1.2 CLASSIFICATION OF SHAMPOOS

• Shampoos classified according to function:

  • Anti-dandruff

  • Medicated

  • 2-in-1 shampoo

  • Mild baby shampoo

  • Basic beauty shampoo

  • Premium conditioning shampoo

9.2 THE ACTION OF SHAMPOO ON THE HAIR

• The primary purpose of shampoo is to cleanse the hair.

• Three basic components of hair soil:

  1. Sebum: oily secretion from sebaceous glands.

  2. Proteinaceous matter: cell debris and sweat.

  3. Atmospheric pollutants and residues from hair-care products.

• Extensive literature exists on sebum's properties; studies highlight its linkage to hair protein through calcium atoms.

Composition of Sebum (Table 9.1)

9.2.1 THE PROCESS OF SOIL REMOVAL

• Types of soil to address:

  • Oily soil (sebum)

  • Soluble soils

  • Insoluble particulate soils

• Full contact with soil is achieved by reducing water surface tension through shampoo surfactants.

• Removal of oily soil occurs via a displacement process, while insoluble soils depend on electrostatic repulsion.

9.3 THE FOAMING OF SHAMPOOS

• Users respond to shampoo based on the speed and abundance of lather.

• Three stages of foaming:

  1. Speed of foam formation

  2. Peak foam volume

  3. Consistency of lather

• Measurement techniques for foaming properties involve assessing how foams develop in varying conditions.

9.4 SHAMPOO INGREDIENTS

• Shampoos are primarily a detergent solution with various additives to enhance application and hair condition.

Ingredients Classification

• Main detergents: Anionic, Nonionic, Amphoteric, Cationics

• Additives:

  • Thickeners

  • Pearlizers and opacifiers

  • Preservatives

  • pH modifiers

  • Functional additives (e.g., proteins, silicones)

9.4.1 Main Detergents

• Class 1: Anionics

  • Types: Alkyl sulfates, Alkyl ether sulfates, Sulfosuccinates, Isothionates.

• Class 2: Nonionics

  • Used as co-surfactants, include fatty acid amides and fatty amine oxides.

• Class 3: Amphoterics

  • Provide mildness and interactive properties with other surfactants.

• Class 4: Cationics

  • Typically not used due to incompatibility with anionics.

9.4.3 FUNCTIONAL ADDITIVES

• Ingredients enhance hair condition:

  • Polyquaterniums

  • Silicone additives

  • Proteins and amino acids

  • Ceramides

  • Panthenol

  • Glutamic acid derivatives

9.5 ANTIDANDRUFF AGENTS

• Zinc pyrithione (ZPT) and piroctone olamine (PO): effective for dandruff treatment; PO tends to have lower irritation.

• Statistical comparison of ZPT and PO showed a slight edge for PO in efficacy.

9.6 PREPARATION AND MANUFACTURE OF SHAMPOOS

• Shampoo preparation is straightforward but requires careful adherence to stability, microbiological integrity, and safety regulations.

• Preparation examples:

  • Simple mixing of functional ingredients and adjusting pH.

  • Dissolving difficult components under specific conditions.

9.7 REPRESENTATIVE SHAMPOO FORMULATIONS

• Frequent Wash Formula: Lowest surfactant concentration for daily use to maintain healthy sebum levels.

• Conditioning Shampoos: Complex formulations that wash and condition simultaneously.

• Premium Shampoos: Higher surfactant levels and additional conditioning agents.

• Antidandruff Shampoos: Utilize active ingredients like ZPT or PO to combat dandruff.

• Baby Shampoos: Focus on low irritancy, often using nonionic detergents to minimize irritation.

Example Ingredients for Different Types of Shampoos

• Two-in-One Conditioning Shampoo: Combination of cleansing and conditioning ingredients.

• Clear Antidandruff Shampoo: Utilizes less irritating active ingredients with good solubility.

• Baby Shampoo: Emphasizes non-irritating formulations suitable for sensitive skin.