Podcast
Questions and Answers
What distinguishes the English or Wet Gum Method from the continental or dry gum method?
What distinguishes the English or Wet Gum Method from the continental or dry gum method?
In the English or Wet Gum Method, what aspect of the primary emulsion can be adjusted by the operator?
In the English or Wet Gum Method, what aspect of the primary emulsion can be adjusted by the operator?
Which statement is true regarding the operational flexibility of the English or Wet Gum Method?
Which statement is true regarding the operational flexibility of the English or Wet Gum Method?
What is a primary characteristic of the English or Wet Gum Method?
What is a primary characteristic of the English or Wet Gum Method?
Signup and view all the answers
Which aspect is NOT considered a part of the English or Wet Gum Method?
Which aspect is NOT considered a part of the English or Wet Gum Method?
Signup and view all the answers
What is the primary purpose of the Bottle or Forbes Bottle Method?
What is the primary purpose of the Bottle or Forbes Bottle Method?
Signup and view all the answers
For which types of substances is the Bottle Method particularly advantageous?
For which types of substances is the Bottle Method particularly advantageous?
Signup and view all the answers
Which characteristic of substances is crucial for the effectiveness of the Bottle Method?
Which characteristic of substances is crucial for the effectiveness of the Bottle Method?
Signup and view all the answers
What is necessary for the preparation of emulsions containing more than one oily liquid?
What is necessary for the preparation of emulsions containing more than one oily liquid?
Signup and view all the answers
Which of these applications is least suitable for the Bottle Method?
Which of these applications is least suitable for the Bottle Method?
Signup and view all the answers
Which type of substance is NOT involved in the creation of emulsions according to the content provided?
Which type of substance is NOT involved in the creation of emulsions according to the content provided?
Signup and view all the answers
What type of oils does the Bottle Method primarily focus on?
What type of oils does the Bottle Method primarily focus on?
Signup and view all the answers
What is the role of the substance that is insoluble in either water or oil in an emulsion?
What is the role of the substance that is insoluble in either water or oil in an emulsion?
Signup and view all the answers
Which statement correctly describes the composition of a stable emulsion?
Which statement correctly describes the composition of a stable emulsion?
Signup and view all the answers
What characteristic is essential for a substance to contribute effectively to an emulsion?
What characteristic is essential for a substance to contribute effectively to an emulsion?
Signup and view all the answers
Study Notes
Emulsion Preparation Methods
- Emulsion preparation methods vary based on emulsion components and available equipment.
- Three common small-scale methods include the dry gum, wet gum, and bottle methods.
Dry Gum Method
- Also known as the 4:2:1 method (4 parts oil, 2 parts water, 1 part gum).
- Acacia or other oil-in-water emulsifiers are thoroughly mixed with oil in a mortar until blended.
- A mortar with a rough surface is used to effectively grind the oil.
- Water is added all at once, then mixed until a creamy white emulsion and a cracking sound result (typically takes about 3 minutes).
- Other liquid ingredients soluble in the external phase (usually water) are mixed in later.
- Solid ingredients (like preservatives or stabilizers) are dissolved in water before being added to the emulsion.
Wet Gum Method
- Similar to the dry gum method but with a different mixing order.
- First, a mucilage (a mixture of gum and water) is prepared.
- Oil is added gradually to this mucilage.
- The mixture is thoroughly mixed to emulsify the oil.
- Additional water and other ingredients are added for proper consistency.
Bottle Method
- Used for volatile oils or less viscous oils.
- Powdered acacia is mixed with oil in a bottle.
- Water is added in portions, shaking after each addition.
- The emulsion is diluted to the required volume with water or an aqueous solution.
- Not suitable for viscous oils.
Emulsion Preparation Types
- More than one oily liquid: Calculate acacia for each oil, then mix. Oil is emulsified separately before mixing.
- Water-soluble substances: Water-soluble substances are dissolved first to avoid de-emulsifying effects.
- Oil-soluble substances: Acacia amount is increased by 50%, and oil-soluble substances are dissolved in the oil before emulsion preparation.
-
Insoluble substances: Finely powdered substances are mixed with acacia used in the primary emulsion formation. Oil is added, and the emulsion is then prepared.
- Examples: Bismuth carbonate in castor oil emulsion and phenolphthalein in liquid paraffin emulsion.
- Small proportion of oily substance: Adding a bland, inert oil (like arachis oil) increases oil content (10-20%) to prevent creaming.
Auxiliary Methods
- Emulsions can be improved by homogenization (using a hand homogenizer).
- Homogenization forces the emulsion through a small orifice, reducing globule size.
- Hand homogenizers are less efficient for very thick emulsions and should not be used with emulsions containing high proportions of solid matter. This can damage the valve.
Emulsion Stability
- Physical stability: Includes creaming (separation of an emulsion into layers) and breaking (irreversible separation of the phases.)
- Chemical stability: Includes factors like incompatibility of emulsifying agents, pH changes, and precipitation of emulsifying agents.
-
Factors affecting creaming:
- Globule/particle size (smaller is better).
- Density difference between the phases (smaller difference is better).
- Viscosity of the external phase (higher viscosity is usually better).
-
Methods to improve emulsion stability: Reducing globule size, minimizing density difference, increasing viscosity of the external phase.
- Upward creaming occurs when the internal phase has lower density; downward creaming when higher.
- Breaking or cracking: A disruption that results from coalescing of globules and separation into layers resulting from incompatibility of the components, bacterial growth, freezing/thawing, or temperature/ storage conditions.
Factors Affecting Stability
-
Chemical instability
- Freezing (ice crystals and solute concentration)
- Oxidation and rancidity (oxygen, antioxidants)
- Microbial activity (microbes, preservatives)
- Environmental factors: Light, air, and microorganisms.
- Storage conditions: Emulsions should be protected from extreme temperatures in order to preserve emulsion stability.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the distinctions between the English or Wet Gum Method and the Bottle Method of emulsion preparation. This quiz covers key characteristics, operational flexibility, and suitable substances for each method. Perfect for students and professionals in pharmaceutical sciences.
