Preparation of Pastes

Definition

• Pastes are semi-solid topical preparations containing a high proportion of solid substances dispersed in a base.
• They are thicker and stiffer than ointments, allowing them to adhere to the skin for extended periods.
• Pastes are used to protect, soothe, and provide localized effects.

Preparation Methods

1. Levigation

   • Solid ingredients are ground into fine powder and then mixed with the paste base to ensure even distribution of the active ingredient.

2. Incorporation

   • Ingredients are mixed together using a mortar and pestle or similar equipment until a homogenous mixture is achieved.
   • The base typically consists of fatty substances like petrolatum and solid ingredients such as zinc oxide or starch.

3. Fusion

   • Ingredients are melted together, then cooled to form a solid paste.
   • This method is less common but used when components need to be melted.

Types of Pastes

1. Fatty pastes
2. Absorptive pastes
3. Emulsion pastes

Uses

• Pastes are used for:
  1. Protection
  2. Absorption
  3. Wound care
  4. Antipruritic and anti-inflammatory effects
  5. Antifungal and antibacterial treatments

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