Presented ByQirtas Tauheed (100-E-14)

Ointments

Definition:“Ointments are semi-solid preparations for application to the skin.”

Types of OintmentsMedicated ointments

Non-medicated ointments

Medicated ointmentsThese contain the medicament either

dissolved or dispersed in the vehicle as fine powders or in the form of micronized powder e.g.

oGentamicin ointment.

Non medicated ointmentsThese are used as vehicles for

preparation of medicated ointments or can be used for their physical effects e.g.

oSoft Paraffin

Properties of ideal ointmentsNon sensitizingNon irritatingPharmaceutically elegantEfficient release of medicament at the site of application

Water -washable

Ointment BasesOintment bases are generally classified by the USP into four groups

I. Oleaginous basesII. Absorption basesIII.Water removable basesIV.Water soluble bases

1)Oleaginous basesOleaginous 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)

Examples of Absorption basesa) Hydrophilic petrolatum

Hydrophilic petrolatum, USP has the following formula for the preparation of 1000 g:Cholesterol 30 gStearyl alcohol 30 gWhite wax 80 gWhite petrolatum 860 g

b) Lanolin¨ obtained from the wool of sheep; ¨ 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

Selection of appropriate Base• Release rate• Topical or percutaneous drug absorption• Occlusion• Stability of drug• Effect of drug on ointment base• Easily removable• Characteristics of surface for application

Preparation of ointmentsOintments are prepared by two general

methods:

- Incorporation- FusionIncorporation

By the incorporation method, the components are mixed until a uniform preparation is attained.

Incorporation of solids: The ointment base is placed on one side of the working surface and the powdered components, previously reduced to fine powders and thoroughly blended in a mortar, on the other side.

Incorporation of solidsThe drug (the pink

powder) is usually the smaller quantity of the two ingredients.

Add an amount of the ointment that is approximately equal in size to the drug.

Incorporation of solidsSpatulate the

mixture.

Continue adding until all of the ointment is used. Spatulate after each addition.

Incorporation of Liquids• Liquid substances are added to an ointment after consideration of an

ointment bases capacity to accept the volume required.

• Small amount of an aqueous solution may be incorporated into an

oleaginous ointment

• Hydrophilic ointment bases readily accept aqueous solution. Addition of

aqueous preparation to a hydrophobic base

• First the aqueous solution incorporated into a small amount of a

hydrophilic base.

• Second that mixture then added to the hydrophobic abase.

Fusion Method Fusion is the act or procedure of liquefying

or melting by the application of heat.By the fusion method, all or some of the

components of an ointment are combined by melted together and cooled with constant stirring until congealed.

Heat labile substances added last, when the temperature of the mixture is low enough not to cause decomposition of the ingredients.

Fusion Method:In a small scale, the fusion process conducted in

a porcelain dish or glass beaker.In large scale, it is carried out in large steam-

jacketed kettles. After congealing the ointment may be passed through an ointment mill (in large scale), in small scale rubbed with spatula or in a mortar to ensure uniform texture.

Packaging, storage, and labelingIn large-mouth ointment jars or in metal or plastic

tubes;In well-closed containers to protect against

contamination and in a cool place to protect against product separation due to heat;

When required light sensitive preparations are packaged or light resistant containers.

In addition to the usual labeling requirements for pharmaceutical products, the USP directs that the labeling for certain ointments and creams include the type of base used (e.g., water-soluble or water-insoluble).

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Pharmaceutical Creams:Creams are semisolid preparations

containing one or more medical agents dissolved or dispersed in either an oil-in-water emulsion or in another type of water-washable base.Many patients and physicians prefer creams to ointments because they are easier to spread and remove than many ointments.