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Ointment bases are classified by the USP into four general groups:

I. Oleaginous (hydrophobic) bases,
II. Water-soluble (hydrophilic) bases,
III. Absorption bases, and
IV. Water removable/washable bases

I. Oleaginous (hydrocarbon) bases:
They are characterized by:
1. Fatty and greasy (provide oily texture to the skin)
2. Have an emollient effect (protect against the escape of moisture)
3. Have occlusive properties (prevent the water loss from the skin leading to skin
hydration and increase skin porosity and drug permeation)
4. Difficult to wash off (as they act as occlusive dressings and can remain on the skin
for long periods without drying out)
5. Water and aqueous preparations may be incorporated (but only in small amounts and
with some difficulty)
6. Combination of these materials can produce bases with a wide range of melting
points and viscosities

Examples of oleaginous (hydrocarbon) bases:
• 3 Forms of HC:
Liquid paraffin - Mineral oil
Semi-solid HC petrolatum – Vaseline
Solid HC – Paraffin

1.Petrolatum, NF (hard, soft and liquid paraffin)
- Soft paraffin or soft petrolatum is also called Vaseline which is yellow in color and thus called
yellow Vaseline
- Synonyms: Yellow petrolatum, Petroleum jelly
- Commercial Product: Vaseline

2. White Petrolatum, USP
- It is petrolatum that has been bleached
- Application: diaper rash, dry skin
- Synonym: White Petroleum Jelly, white soft paraffin
- Commercial Product: White Vaseline

3. Yellow and White Ointment, USP
- Each 100 g contains 5 g yellow wax and 95 g of petroleum
- Synonym: Simple Ointment

4. Oils and fats
- Vegetable fixed oil like castor and peanut oil
- Waxes as bees wax
- Hydrogenated vegetable oil, unstable due to increasing melting point and need addition of
antioxidants

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