40 Questions
What is the characteristic of the ointment base that is water-soluble?
Easily washed off the skin and clothes
Which of the following is a disadvantage of water-soluble ointment bases?
They are non-occlusive
What is the main characteristic of type A anhydrous ointment base?
Insoluble in water
Which of the following is an example of a hydrophilic ointment base?
Gelatin
What is the characteristic of type B hydrophobic ointment base?
Insoluble in water
Which of the following is NOT a characteristic of water-soluble ointment bases?
Difficult to wash off the skin
What is the main characteristic of type C water-soluble ointment base?
Water-soluble
Which of the following is an example of an emulsion ointment base?
Cold cream
What is the advantage of absorption bases?
Being highly compatible with most drugs
What is the main difference between W/O emulsion and O/W emulsion?
The external phase of the emulsion
What is the function of beeswax in ointment preparations?
As a stiffening agent
What is the advantage of O/W emulsion ointment bases?
They are water-washable
What is the composition of Hydrous Wool fat (lanolin)?
70% wool fat + 30% purified water
What is the property of O/W emulsion ointment bases?
Miscible with water
What is the disadvantage of W/O emulsion ointment bases?
Being highly greasy
What is Whitfield’s Ointment commonly used for?
As an antifungal agent
Which type of base is characterized by being insoluble in water and not water removable?
B- Hydrophobic base
What is the main characteristic of Absorption bases (emulsifiable bases)?
They allow incorporation of aqueous solutions
Which of the following is an example of a Hydrophilic Absorption base?
Cold cream
What is the advantage of using Absorption bases (emulsifiable bases) in ointment preparation?
They allow incorporation of aqueous solutions and retain their ointment-like consistency
Which type of Absorption base does not contain water but contains a w/o emulsifying agent?
Anhydrous Absorption base
What is the characteristic of a Hydrous Absorption base?
It is a w/o emulsion that accepts addition of more aqueous solution up to 50% of its weight
What is the advantage of using ointment bases that allow incorporation of aqueous solutions?
They allow adding aqueous drugs and absorbing exudates from moist lesions
Which of the following is an example of an Anhydrous Absorption base?
Wool fat (anhydrous lanolin)
What is a characteristic of water-washable ointment bases?
Easily removed from skin and clothing
Why do patients prefer creams over ointments?
Because creams spread more readily and are washable
What is a disadvantage of hydrophilic ointment bases?
They are subject to mold growth
What is a characteristic of water-soluble ointment bases?
They soften with the addition of water
What is a property of polyethylene glycol (PEG)?
It is a polymer of ethylene oxide
What is a characteristic of PEGs with higher molecular weights?
They are wax-like, white solids with increasing hardness
What is an advantage of water-soluble ointment bases?
They are greaseless
What is another example of a water-soluble ointment base?
Gelatin
What is the primary advantage of oleaginous bases in terms of skin hydration?
They form a water-proof film that inhibits water loss from the skin
Which of the following is a characteristic of oleaginous bases?
Hydrophobic and water insoluble
What is the primary disadvantage of oleaginous bases in terms of application?
They are unpleasant to apply and can stain clothing
Which of the following is a type of oleaginous base?
Yellow Petrolatum
Why are oleaginous bases poor at incorporating water-soluble drugs?
Because they have a low water absorption capacity
What is the advantage of using white Petrolatum over yellow Petrolatum?
It is more pleasant to apply and less likely to stain clothing
What is a disadvantage of oleaginous bases in terms of drug release?
They have a slow or unsure drug release
Why are oleaginous bases good emollients?
Because they form a water-proof film that inhibits water loss from the skin
Study Notes
Classification of Ointment Bases
- Ointment bases can be classified into four main categories: Oleaginous, Absorption, Emulsion, and Water-Soluble bases.
Oleaginous Bases
- Characteristics:
- Anhydrous (do not contain water)
- Hydrophobic (do not absorb water)
- Insoluble in water
- Not water-removable (difficult to wash off)
- Examples:
- Petrolatum (Vaseline)
- Fixed oils of vegetable origin (olive oil, cottonseed oil)
- Oils and fats of animal origin (lard)
- Advantages:
- Highly inert and compatible with most drugs
- Easily spread on skin
- Readily available and cheap
- Remain on skin for a prolonged period without drying out
- Good emollients (keep skin hydrated and soft)
- Improve penetration of drugs through skin
- Disadvantages:
- Sticky and unpleasant to apply
- Difficult to remove from skin and clothing
- May rancid on storage
Absorption Bases
- Characteristics:
- Allow incorporation of aqueous solutions
- Can absorb quantities of water or aqueous medication
- Form w/o emulsions and retain ointment-like consistency
- Examples:
- Lanolin (anhydrous lanolin)
- Hydrous wool fat (lanolin)
- Beeswax
- Advantages:
- Highly compatible with most drugs (hydrophilic and lipophilic)
- Easier to spread
- Can absorb exudates from moist lesions
- Disadvantages:
- Greasy and non-washable
- Less occlusive than oleaginous bases
Emulsion Bases
- Characteristics:
- O/W emulsions
- Hydrous (contain water)
- Hydrophilic
- Insoluble in water
- Water-removable
- Examples:
- Hydrophilic ointment
- Vanishing cream
- Whitfield's Ointment (Compound Benzoic Acid Ointment)
- Advantages:
- Non-greasy
- Water-washable
- Better cosmetic appearance
- Good contact with skin
- Disadvantages:
- Non-occlusive
- Subject to mold growth (require preservatives)
Water-Soluble Bases
- Characteristics:
- Anhydrous
- Hydrophilic
- Water-soluble
- Water-removable
- Greaseless
- Examples:
- Polyethylene glycol (PEG) polymers
- Polyethylene oxide (PEO)
- Gelatin
- Pectin
- Sodium alginate
- Advantages:
- Non-greasy
- Water-soluble
- Good solvent properties for water-soluble dermatological drugs
- No water content, so no hydrolysis, rancidity, or microbial growth
- Disadvantages:
- None mentioned
This quiz covers the advantages and disadvantages of macrogols, a type of pharmaceutical product. Learn about their solubility, absorption, and solvent properties, as well as their limitations.
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