18 Questions
What type of emulsion is milk, and what is the dispersed phase?
Milk is an oil in water (O/W) emulsion, where oil is the dispersed phase.
How do emulsions improve the stability of drugs?
Emulsions increase the stability of many drugs that are unstable in aqueous solutions.
What is the advantage of using O/W emulsions for orally administering water-insoluble liquids?
O/W emulsions facilitate the absorption of water-insoluble compounds, making them more convenient for oral administration.
What is the benefit of using emulsions in cosmetic applications?
Emulsions improve penetration and spreading ability, making them suitable for cosmetic applications such as skin creams.
How do emulsions enhance the absorption of oil-soluble drugs?
Emulsions enhance the rate and extent of absorption of oils and oil-soluble drugs through the alimentary canal.
What is the benefit of using emulsions as diagnostic agents?
Emulsions can be used as diagnostic agents, such as radiopaque emulsions in x-ray examinations.
What is the HLB value of a mixture of surfactants with a ratio of 40:60, consisting of Sorbitan monostearate (Span 60) and Polysorbate 60 (Tween 60)?
10.07
What is the main purpose of adding antioxidants to an emulsion formulation?
To prevent degradation of oils by oxidation
What is the primary function of antimicrobial preservatives in emulsions?
To prevent microbial growth and spoilage
Which of the following emulsifying agents has the highest HLB value?
Polysorbate 20 (Tween 20) with an HLB value of 16.7
What is the role of emulsifying agents in emulsion formulation?
To stabilize the emulsion by reducing the interfacial tension between the oil and water phases
What is the purpose of minimizing the initial mixing time of gum and oil in emulsion preparation?
To prevent the gum from imbibing the oil and becoming waterproof.
Why are emulsions commonly used in cosmetic applications?
Because they can combine the benefits of oil-soluble and water-soluble ingredients in a single product
What is the purpose of passing an emulsion through a hand homogenizer?
To reduce the dispersed droplet size to about 5 microns or less.
What is the in situ soap method used for in emulsion preparation?
To form an o/w or w/o emulsion by mixing oil and an aqueous solution containing an alkali like calcium hydroxide.
What is the role of calcium oleate in the preparation of calamine lotion?
It acts as an emulsifying agent.
What is the purpose of labeling emulsions with 'Shake well before use'?
To ensure proper mixing of the emulsion before use.
What type of containers are used for very viscous emulsion preparations?
Wide mouthed amber bottles.
Study Notes
Pharmaceutical Applications of Emulsions
- Ointments and vitamin drops are examples of pharmaceutical applications of emulsions.
- Emulsions improve the taste of objectionable medicinal agents and make them more acceptable.
- O/W emulsions facilitate the absorption of water-insoluble compounds.
- Emulsions can be used for external application in cosmetic and therapeutic uses.
Advantages of Emulsions
- Emulsions increase stability of many drugs, which are unstable in aqueous solution.
- Emulsions improve penetration and spreading ability.
- Emulsions enhance the rate and extent of absorption of oils and oil-soluble drugs through the alimentary canal.
- Emulsions can be used as diagnostic agents, e.g., radiopaque emulsion in x-ray examination.
- Emulsions improve solubility of many drugs, which have limited solubility in aqueous phase.
- Emulsions can prolong drug action.
Emulsions in Everyday Life
- Examples of emulsions include pesticide, asphalt, skin cream, metal cutting oils, margarine, and ice cream.
- Milk is an O/W emulsion, while balm is a W/O emulsion.
HLB (Hydrophile-Lipophile Balance) Value
- HLB value is a measure of the balance between hydrophilic and lipophilic properties of an emulsifier.
- HLB values of different emulsifying agents/surfactants are listed, ranging from 1.8 to 16.7.
Formulation of Emulsions
- Antioxidants may be added to prevent degradation of oils by oxidation.
- Antimicrobials are added to prevent microbial growth in the aqueous phase of emulsions.
- Minimizing the initial mixing time of gum and oil is important to prevent the gum from becoming water-proof.
Auxiliary Methods
- Passing an emulsion through a hand homogenizer can improve its stability and reduce the dispersed droplet size.
In Situ Soap Method
- This method involves mixing equal volumes of an oil and an aqueous solution containing a sufficient amount of alkali.
- Suitable for the formation of O/W or W/O emulsions.
Examples of Emulsions
- Internal use: cod liver oil emulsion, liquid paraffin emulsion, and castor oil emulsion.
- External use: turpentine liniment BP, oily calamine lotion BP.
Storage, Containers, and Labeling
- Storage: temperature not exceeding 20°C, and not allowed to freeze.
- Containers: wide mouthed amber bottle for very viscous preparations, and airtight child-resistant closure.
- Labeling: shake well before use, store in a cool place, expiry date, and for external use only.
General Types of Pharmaceutical Emulsions
- Lotions
- Liniments
- Creams: O/W-aqueous cream, W/O-oily cream.
Explore the advantages of oil-in-water (O/W) emulsions in pharmaceutical applications, including improving taste, enhancing absorption, and facilitating parenteral administration. Learn how O/W emulsions are used in various medicinal forms, such as ointments and vitamin drops.
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