Ointments

• Ointments, creams, and gels are semisolid dosage forms intended for topical application.

  • May be applied to skin, surface of the eye, or nasally, vaginally, or rectally.
  • Most of these preparations are used for the effects of the therapeutic agents they contain.
  • Unmedicated ones are used for their physical effects as protectants or lubricants.
• Topical preparations are used for both local and systematic effects

  • Topical drug (API) dosage form – designed to deliver the drug into the skin in treating skin disorders where the skin is the target organ.
  • Systematic drug absorption should always be considered when using topical products if the patient is pregnant or nursing because drugs can enter the fetal blood supply and breast milk.
• Topical dermatological product is designed to deliver drug into the skin in treating dermal disorders, with the skin as the target organ.
• Transdermal product is for delivering drugs through the skin (percutaneous absorption) to the general circulation for systemic effects, skin is not the target organ.
• Ointments

  • Semisolid preparations intended for external application to the skin or mucous membranes.
  • May be medicated or not
  • Unmedicated ointments are used for physical effects they provide as protectants, emollients, or lubricants
• Ointment Bases

  • May be used for their physical effects or as vehicles for medicated ointments
  • USP classified into four groups
  • Oleaginous bases
  • Absorption bases
  • Water-removable bases
  • Water-soluble bases
• Oleaginous Bases

  • Also termed hydrocarbon bases. On application to the skin, they have an emollient effect, protect against the escape of moisture, are effective as occlusive dressings, can remain on the skin for long periods without drying out, and difficult to wash of because of their immiscible aqueous preparations.
  • Petrolatum, white petrolatum, white ointment, and yellow ointment are examples of hydrocarbon ointment bases.
  • When powdered substances are to be incorporated into hydrocarbon bases, liquid petrolatum (mineral oil) may be used as the levigating agent.
• Petrolatum USP

  • is a purified mixture of semisolid hydrocarbons obtained from petroleum. It is an unctuous mass, varying in color from yellowish to light amber.
  • melts at 38°C to 60°C, may be used alone or in combination with other agents as an ointment base
  • also known as yellow petrolatum and petroleum jelly.
  • Commercial product example is Vaseline (Chesebrough-Ponds)
• White Petrolatum USP

  • a purified mixture of semisolid hydrocarbons from petroleum that has been wholly or nearly decolorized. It is used for the same purpose as petrolatum
  • Considered more esthetically pleasing because of its lighter color
  • Also known as white petroleum jelly
  • Commercial product example is White Vaseline Chesebrough-Ponds)
• Yellow Ointment USP

  • has the following formula for the preparation of 1,000g: Yellow wax: 50g Petrolatum: 950g
  • Yellow wax is the purified wax obtained from the honeycomb of the bee Apis mellifera.
  • Yellow ointment is prepared by melting the yellow wax on a water bath, adding the petrolatum until the mixture is uniform, and then cooling and stirring until congealed
  • Also called simple ointment, has a slightly greater viscosity than plain petrolatum.
• White ointment USP

  • differs from yellow ointment by substitution of white wax (bleached and purified yellow wax) and white petrolatum in the formula.
• Absorption Bases

  • Types:
  • those that permit the incorporation of aqueous resulting in the formation of water-in-oil (W/O) emulsion (e.g. hydrophilic petrolatum)
  • those that are W/O emulsions (syn: emulsion bases) that permit the incorporation of additional quantities of aqueous solution (e.g. lanolin).
• Absorption Bases

  • May be used as emollients, although they do not provide the degree of occlusion afforded by the oleaginous bases.
  • Not easily removed from the skin with water washing, because the external phase of the emulsion is oleaginous.
  • Useful as pharmaceutical adjuncts to incorporate small volumes of aqueous solutions into hydrocarbon bases.
  • This is accomplished by incorporating the aqueous solution into the absorption base and then incorporating this mixture into the hydrocarbon base.
• Hydrophilic Petrolatum USP


  Formula for preparation of 1,000 g:
• Hydrophilic Petrolatum USP Ingredients

  • Cholesterol: 30 g
  • Stearyl alcohol: 30 g
  • White wax: 80 g
  • White petrolatum: 860 g
• Hydrophilic Petrolatum USP Preparation

  1. Melt stearyl alcohol and white wax on steam bath

  2. Add cholesterol with stirring until dissolved

  3. Add white petrolatum

  4. Allow mixture to cool while stirring until congealed
• (Hydrophilic Petrolatum USP) Commercial products: Aquaphor and Aquabase

  • Variations of hydrophilic petrolatum
  • Capacity to absorb up to three times their weight in water
• Absorbing water


  Helps incorporate water-soluble drug (e.g. tobramycin sulfate) into oleaginous ointment base
• This concept is used in the preparation of ophthalmic ointments
• Eucerin


  50% W/O emulsion
• Lanolin USP

  • (anhydrous lanolin) obtained from the wool of sheep (Ovis aries), is a purified wax-like substance that has been cleaned, deodorized, and decolorized.
  • It contains not more than 0.25% water.
  • Additional water may be incorporated into lanolin by mixing.
• Modified Lanolin USP

  • is lanolin processed to reduce the contents of free lanolin alcohols and any detergent and pesticide residues.
• Water-Removable Bases

  • Are oil-in-water emulsions commonly called creams
  • Because the external phase of the emulsion is aqueous, they are easily washed from skin and are often called water-washable bases.
  • May be diluted water or aqueous solutions
  • Can absorb serous discharges
• Hydrophilic Ointment USP Ingredients

  • It has the following formula for 1,000 g: (grams) Methylparaben: 0.25 Propylparaben: 0.15 Sodium lauryl sulfate: 10.00 Propylene glycol: 120.00 Stearyl alcohol: 250.00 White petrolatum: 250.00 Purified water: 370.00
• Hydrophilic Ointment USP

  • The stearyl alcohol and white petrolatum are melted together at about 75°C.
  • The other agents, dissolved in the purified water, are added with stirring until the mixture congeals.
  • Sodium lauryl sulfate is the emulsifying agent, with the stearyl alcohol and white petrolatum constituting the oleaginous phase of the emulsion and the other ingredients the aqueous phase.
  • Methylparaben and propylparaben are antimicrobial preservatives.
• Water-Soluble Bases

  • Water-soluble bases do not contain oleaginous components.
  • Polyethylene glycol (PEG) ointment, NF, is the prototype example of a water-soluble base.
  • 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 incorporation of solid substances.
• Polyethylene Glycol Ointment, NF

  • PEG is a polymer of ethylene oxide and water.
  • Represented by the formula H(OCH2CH2)nOH, in which n represents the average number of oxyethylene groups.
  • The numeric designations associated with PEGs refer to the average molecular weight of the polymer.
  • PEGs having average molecular weight:
  • Below 600 are clear, colorless liquids;
  • Above 1,000 are wax like white materials;
  • Those with molecular weight in between are semisolids.
  • Greater molecular weight = greater viscosity
• Polyethylene Glycol Ointment, NF

  • The NF lists the viscosity of PEGs ranging from average molecular weight of 200 to 8,000.
  • The general formula for preparation of 1,000 g of PEG ointment is: PEG 3350: 400 g PEG 400: 600 g
  • Combining PEG 3350, a solid, with PEG 400, a liquid, results in a very pliable semisolid ointment.
• Polyethylene Glycol Ointment, NF

  • If a firmer ointment is desired, the formula may be altered to contain up to equal parts of the two ingredients.
  • When aqueous solutions are to be incorporated into the base, substitution of 50g of PEG 3350 with an equal amount of stearyl alcohol is advantageous in rendering the final product firmer.
• Selection of Appropriate Base (Factors)

  • Desired release rate of the drug substance from the ointment base
  • Desirability of topical or percutaneous drug absorption
  • Desirability of occlusion of moisture from the skin
  • Stability of the drug in the ointment base
  • Effect, if any, of the drug on the consistency or other features of the ointment base
  • Desire for a base easily removed by washing with water
  • Characteristics of the surface to which it is applied
• Selection of Appropriate Base

  • For example, an ointment is generally applied to dry, scaly skin; a cream is applied to weeping or oozing surfaces; and a lotion is applied to intertriginous areas or where friction may occur, as between the thighs or under the armpit.
  • The base that provides the best combination of the most desired attributes should be selected.
• Preparation of Ointments

  • Incorporation
  • Fusion
• Incorporation

  • The components are mixed until a uniform preparation is attained.
  • On a small scale, in extemporaneous compounding, the pharmacist may mix the components using a mortar and pestle, or a spatula may be used to rub the ingredients together on an ointment slab (a large glass or porcelain plate or pill tile).
• Incorporation

  • Some pharmacists use nonabsorbent parchment paper to cover the working surface. The paper eliminates cleaning the ointment slab.
  • If using an ointment parchment pad, it's best not to allow too long contact between ointment and the parchment as it may soften and tear.
• Incorporation

  • Others use an ointment mill
  • An electronic mortar and pestle, or a device called Unguator.
  • Allows pharmacists to place the ingredients in a plastic ointment jar with a special lid that allows for a mixing blade to be used to mix the ingredients in the dispensing container.
  • Can be controlled manually or via computer software.
• Incorporation of Solids

  • When incorporating solids during preparation by spatulation, the pharmacist works the ointment with a stainless steel spatula having a long, broad blade and periodically removes the accumulation of ointment on the large spatula with a smaller one.
  • If the components react with metal (as does iodine), hard rubber or silicone spatulas may be used.
  • Ointment is prepared by thoroughly rubbing and working the components together on the hard surface until the product is smooth and uniform.
• 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.
  • A small portion of the powder is mixed with a portion of the base until form.
  • Geometric dilution is continued until all portions of the powder and base are combined thoroughly and uniformly blended.
• Levigation

  • It is often desired to reduce the particle size of a powder or crystalline material before incorporation into the ointment base so the final product will not be gritty.
  • This may be done by levigating, or mixing the solid material in a vehicle in which it is insoluble to make a smooth dispersion.
• Levigating Agents

  • mineral oil for bases in which oils are the external phase
  • glycerin for bases in which water is the external phase
• Levigating Agents

  • should be physically and chemically compatible with the drug and base.
  • It should be about equal in volume to the solid material.
  • Mortar and pestle method are used for levigation
  • This allows both reduction of particle size and dispersion of the substance in the vehicle.
  • This is preferred when large volumes of liquid are added because the liquid is more captive than on an ointment slab.