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Ointment

An ointment is a homogeneous, viscous, semi-solid preparation, most commonly a greasy, thick 

oil (oil 80% - water 20%) with a high viscosity, that is intended for external application to theskin or mucous membranes. They are used as emollients or for the application of active

ingredients to the skin for protective, therapeutic, or prophylactic purposes and where a degree

of occlusion is desired.

Ointments are used topically on a variety of body surfaces. These include the skin and the

mucous membranes of the eye (an eye ointment ), vagina, anus, and nose. An ointment may or

may not be medicated.

Ointments are usually very moisturizing, and good for dry skin. They have a low risk of 

sensitization due to having few ingredients beyond the base oil or fat, and low irritation risk.

There is typically little variability between brands of generics and name brand drugs. They areoften disliked by patients due to greasiness

Ointment bases

The vehicle of an ointment is known as the ointment base. The choice of a base depends upon

the clinical indication for the ointment. The different types of ointment bases are:

 Hydrocarbon bases, e.g. hard paraffin, soft paraffin, microcrystalline wax and ceresine

 Absorption bases, e.g. wool fat, beeswax Water soluble bases, e.g. macrogols 200, 300, 400

 Emulsifying bases, e.g. emulsifying wax, cetrimide

 Vegetable oils, e.g. olive oil, coconut oil, sesame oil, almond oil and peanut oil. 

The medicaments are dispersed in the base, and later they get divided after the drug penetration

into the living cells of skin.

Ointments are formulated using hydrophobic, hydrophilic, or water-emulsifying bases to provide

preparations that are immiscible, miscible, or emulsifiable with skin secretions. They can alsobe derived from hydrocarbon (fatty), absorption, water-removable, or water-soluble bases.

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IDEAL OINTMENT BASE Ideal ointment base should have following physicochemical properties:

1.  Stability2.  Neutral in reaction

3.  Non greasy

4.  Non degreasing5.  Non irritating

6.  Nondehydrating

7.  Non hygroscopic8.  Water removable

9.  Compatible with all medicaments

10.  Free from odors

Ointment Properties Nonstaining

 Efficient on all skin type

 Composed of readily available component of known chemical composition

 Capable of holding 50% of water

 Easily compounded

 Melting & softening at body temperature

 smoothness

 ease of application

 Suitable base

 Properly distributed medicament

CLASSIFICATION OF OINTMENT ACCORDING TO PENETRATION:

1.EPIDEMIC OINTMENT : 

• Slight penetration power

• Therapeutic effect on diseased epithelium

• e.g,petrolatum,waxes and 1+2.

2.ENDODERMIC OINTMENT: • Power of deeper penetration

• e.g,vegi oils,lards,lanolin and 1+2+3

3.DIADERMIC OINTMENT: • Penetrate skin effectively. better absorption• e.g., emulsion type & water soluble.

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Evaluation of ointments

1. 

Drug content2.  Release of medicament from base3.  Medicament penetration

4.  Consistency of the preparation

5.  Absorption of medicament into blood stream

6.  Irritant effect

Properties which affect choice of an ointment base are:

1.  Stability2.  Penetrability

3.  Solvent property4.  Irritant effects

5.  Ease of application and removal

Methods of preparation of ointments

METHOD OF PREPARATION BY FUSION : 

• The constituents of the base are melted together in the basin and stirred gently after meltinguntil cool.

• Vigorous stirring can cause aeration which should be avoided.

• Any foreign particles that are naked on melting cam be removed by decantation or by using awarm muslin cloth.

• If product is granular after cooling due to separation of some ingredients of high MP, it may be

remelted with min. heat and restirred until cold.

• Stock bases can be made successfully by pouring the melted mixture into a warmed jar,covering and allowing to stand, undisturbed on a non conducting surface, until set. (paraffin,

simple or wool alcohol ointments of B.P.)

• Completely or partially soluble solids should be added in fine powder to the molten base atvery low temperature and the mixture stirred until cold.

• Liquids such as methyl salicylate and coal tar solutions and semi solids such as ichthammolshould be added just as the base is thickening, at about 40C. When a solid is soluble in liquidingredient, (menthol in methyl salicylate), its more convenient to add it in solution.

• Insoluble solids (calamine, starch, zinc oxide) should be passed through a 180 um sieve andadded in small amount while stirring to melted base, when it shows first sign of thickening.Sedimentation should be prevented.

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• If the product has liquid paraffin or a fixed oil, small amount can be used to levigate powderbefore adding to base to produce a smoother product.

METHOD OF PREPARATION MIXING BY TRITURATION :

• This is applicable when medicament is a solid insoluble in base or a liquid present in smallamount.

• Solids should be finely powdered and passed via sieve. (250 um/180 um/125 um mesh).• Trituration can be carried out with an ointment tile and a spatula or using mortar and pestle.

METHOD OF PREPARATION TRITURATION USING TILE AND SPATULA:

Tiles should be large enough to prepare ointments.

• Spatula should be flexible and have a broad, non-tapering long blade, to provide a large rubbingsurface.

• Another small spatula may be used for removing accumulated material.

• Powders for incorporation are placed on the tile and mixed gently.

• Powders are levigated until mixture is smooth and homogenous.• Dispersion is then diluted with increasing amounts of base, doubling the quantity on each

addition.

• Finally any liquid ingredients are incorporated, avoiding splashes.