Ointment bases Classification, Use of Ointment bases and MCQs for GPAT, NIPER, Pharmacist and Drug Inspector exam
Ointment bases are generally classified by the USP into four groups
I. Oleaginous bases
II. Absorption bases
III. Water removable bases
IV. Water soluble bases
1)Oleaginous bases – Oleaginous bases are also termed as hydrocarbon bases. On application to the skin emollient effect occlusive dressings protect against the escape of moisture.
Examples of Oleaginous Bases a)Petrolatum (USP) is a purified mixture of semisolid hydrocarbons obtained from petroleum. A commercial product is Vaseline.
b) White Petrolatum(USP) is a purified mixture of semisolid hydrocarbons from petroleum that has been wholly or nearly decolorized.
c)Yellow ointment (USP) is mixture (1000g) of yellow wax (50g) and petrolatum (950g).
d)White ointment (USP) This ointment differs from yellow ointment by substituting white wax and white petrolatum in the formula.
2) Absorption bases – Absorption bases are of two types:
Those that permit the incorporation of aqueous solutions resulting in the formation of water-in-oil emulsions (e.g., hydrophilic petrolatum)
Those that are water-in-oil emulsions and permit the incorporation of additional quantities of aqueous solutions (e.g., Lanolin) obtained from the wool of sheep;
Examples of Absorption bases
a) Hydrophilic petrolatum Hydrophilic petrolatum, USP has the following formula for the preparation of 1000 g: Cholesterol 30 g Stearyl alcohol 30 g White wax 80 g White petrolatum 860 g
b) Lanolin is a purified, wax-like substance that has been cleaned, deodorized, and decolorized.
3) Water-removable bases – Water-removable bases are oil-in-water emulsions resembling creams in appearance. Because the external phase of the emulsion is aqueous, they are easily washed from skin and are often called ‘water washable’ bases. They may be diluted with water or aqueous solutions e.g. Hydrophilic ointment.
4) Water-soluble bases – Water-soluble bases do not contain oleaginous components. They are completely water-washable and often referred to as ‘greaseless’. Because they soften greatly with the addition of water, large amounts of aqueous solutions are not effectively incorporated into these bases. They mostly are used for the incorporation of solid substances. E.g. Polyethylene glycol ointment.
Petrolatum:
INN: Yellow soft paraffin; Yellow petrolatum; Petrolatum
Synonyms: Yellow Soft Paraffin; Amber Petrolatum; Yellow Petrolatum; Petroleum Jelly; Paraffin Jelly; Mineral Jelly; vaselinum flavum
Chemical Name & CAS Number: Petrolatum (8009-03-8)
Molecular Formula: Purified mixture of saturated hydrocarbons with the general formula CnH2n+2
Description: Unctuous mass of yellowish to light amber color; not more than a slight fluorescence after being melted; transparent in thin layers; free or nearly free from odor and taste.
Properties: Insoluble in water; almost insoluble in cold or hot alcohol or in cold dehydrated alcohol; specific gravity 0.815- 0.880 at 60°C; melts between 38 and 60°C.
Uses: As an ointment base, emollient.
Multiple choice questions:
1.Ointment bases are generally classified by the USP into ____ groups.
a)1
b)2
c)3
d)4
2.Which of the following are types of ointment bases?
a)Oleaginous bases
b)Absorption bases
c)Water removable bases
d)All of these
3.Oleaginous bases are also termed as
a)hydrocarbon bases
b)water soluble bases
c)emulsifying bases
d)none of these
4.Examples of Oleaginous Bases are
a)Petrolatum
b)White Petrolatum
c)Yellow ointment
d)All of these
5.Which is a purified mixture of semisolid hydrocarbons obtained from petroleum?
a)Petrolatum
b)White Petrolatum
c)Yellow ointment
d)White ointment
6.Which is a purified mixture of semisolid hydrocarbons from petroleum that has been wholly or nearly decolorized?
a)Petrolatum
b)White Petrolatum
c)Yellow ointment
d)White ointment
7.Which ointment mixture is a composition of yellow wax (50g) and petrolatum (950g)?
a)Petrolatum
b)White Petrolatum
c)Yellow ointment
d)White ointment
8.This ointment is substituting of white wax and white petrolatum in the formula
a)Petrolatum
b)White ointment
c)Hydrophilic petrolatum
d)None of these
9.Absorption bases are of ___ types
a)1
b)2
c)3
d)4
10.Those absorption bases that permit the incorporation of aqueous solutions resulting in the formation of water-in-oil emulsions is/are
a)Petrolatum
b)White ointment
c)Hydrophilic petrolatum
d)c)Yellow ointment
11.A purified, wax-like substance that has been cleaned, deodorized, and decolorized is
a)Lanolin
b)Hydrophilic petrolatum
c)Cholesterol
d)Stearyl alcohol
12._____ bases are oil-in-water emulsions resembling creams in appearance.
a)Water-soluble bases
b)Water-removable bases
c)Absorption bases
d)Oleaginous bases
13.Which of the following bases are often referred to as ‘greaseless’?
a)Water-soluble bases
b)Water-removable bases
c)Absorption bases
d)Oleaginous bases
14.Which of the following is/are synonyms of Petrolatum?
a)Yellow Soft Paraffin
b)Amber Petrolatum
c)Mineral Jelly
d)All of these
15.Petrolatum is used as
a)ointment base
b)emollient
c)both of these
d)absorbent
Solutions:
- d)4
- d)All of these
- a)hydrocarbon bases
- d)All of these
- a)Petrolatum
- b)White Petrolatum
- c)Yellow ointment
- b)White ointment
- b)2
- c)Hydrophilic petrolatum
- a)Lanolin
- b)Water-removable bases
- a)Water-soluble bases
- d)All of these
- c)both of these
References:
- Remington Essential of Pharmaceutics, 1st edition 2013, page no. 697.
- Raymond C Rowe Handbook of Pharmaceutical Excipients, 6th edition, page no. 481-484.
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