Ointments are viscous semi-solid preparations intended only for external use.

They can be used: on skin, surface of eyes (ophthalmic), nasally, vaginally, rectally.

Aim of ointments: Local or systemic effects

Contain drug or not: May be used as moisturizer only 

1.  Hydrocarbon or Fatty or Oleaginous base

2.  Absorption base

3.  Water removable base

4.  Water soluble base 

Water content of the base

Affinity for water (Allows incorporation of water)

Spreadability of ointments prepared with such base

Washability of ointments prepared with such base

Drug incorporation potential

Occlusiveness

Uses

Disadvantages 

- Solids or Oils

- Allows very small incorporation of aqueous solutions or hydrophilic agents 

- Emolients, moisturizer

- Retention on the skin for long time

-vehicles for hydrolyzable drugs 

Mixture of semisolid hydrocarbons obtained from petroleum

Decreased melting point (38-60 C)

Yellow petrolatum or petrolatum jelly

White petrolatum: decolorized, more esthetically pleasing, very used in ointments to treat diaper rashes 

Mixture of petrolatum (5%) and purified yellow wax (95%) extracted from bee honeycomb

White ointment: bleached and purified white wax + white petrolatum 

- Ointments with various consistencies - often used at 10% to prepare Soft Petrolatum Base

- Mineral oil also used as levigating agent 

Anhydrous hydrophilic bases that allow incorporation of water to form w/o emulsions: fatty compounds + w/o surfactant. 

-Contain an emulsifier agent

- Emulsion formed when aqueous solution (with or without drug) is added

Hydrous bases that are w/o emulsions: fatty compounds + less water + w/o surfactant

- Also allow incorporation of additional water 

Hydrophilic Petrolatum

Cholesterol 3%

Stearyl Alcohol 3%

White Wax 8%

White Petrolatum 86%

Commercially available bases: Aquafor 

- Solids or oils

- Allows very little incorporation of aqueous solutions or hydrophilic agents 

- Emolients

-Vehicls for drugs instable in water

- For aqueous solutions

- Non-hydrolyzable drugs 

- Solids or oils

- Allows very little incorporation of aqueous solutions or hydrophilic agents 

Hydrous Lanolin: Can be incorporated in other formulations

Wax-like substance, contains 0.25% water, allows additional water.  Too viscous, allergic reaction. 

Made of oil component + water + o/w surfactants

- Most common oitment base used

- Water content >45%

- Drug release from the ointment is generally fast 

- Solids: water soluble or decreased amounts of insoluble compounds

- Allows dilution with water

Polymers of ethylene oxide

Wide range of moelcular weights: 300,400,1000,6000

MW > 600: Clear, colorless liquids

600< MW < 1000: semi solids

MW < 1000: white, wax-like materials

Increase MW, increase viscosity

Polyethylene glycol ointment: obtained by mixing PEGs with varied MW (for water incorporation, replace 5g PE 3350 for stearyl alcohol) 

- Characteristics of surface to be applied

- Desired consistency

- Is occlusive effect desired?

- Stability of the drug and incompatibilities

- Solubility of the drug

- Washability of the ointment

- Release rate of the drug

- Topical vs systemic 

Hydrocortisone acetate, Cortaid cream and ointment (Pharmacia and Upjohn), Triamcinolone Acetonide, Aristocort A cream and ointment (Fujisawa)

Steroids --> Inflammatory dermatoses 

Polymixin B sulfate + Bacitracin zinc + Neomycin, Neosporin Ointment (GlaxoSmithKline)

Anti-bacterial --> Skin Infections 

Nitroglycerin Ointment, Nitro-Bid ointment (Hoechst Marion Roussell)

These are Anti-Anginal --> Smooth Muscle Relaxation of peripheral arteries and veins 

Ophthalmic ointments are applied to the cornea of the eye.  Delivery is limited by....

- Structure and decreased permeability of cornea

- Short residence time of drug on the surface of eye

- Small surface area of cornea 

- Provide extended residence time on the surface of the eye

- Ointment clearance: 0.5% of their volume/min

- Solutions clearance: 16% of their volume/min 

Must have a softening point close to body temperauture

-White petrolatum + mineral oil

- Gel-base: PEG + mineral oil, allow incorporation of hydrophilic and lipophilic drugs 

Treatment of anorectal conditions is needed for.....

- Inflammation

- Pruritis

- Pain and discomfort associated with hemorroids

A treatment for hemorrhoids is Starch, Anusol (Glaxo-SmithKline) 

Treatment of vulva conditions, vaginal infections, contraception (spermatocidal agents)

-Contain applicators

Mucosa: Stratified non-keratinized squamos epithelial tissue.

Submucosa: Vascularized connective tissue with no glands

Muscular: Smooth muscle

Vaginal epithelial surface is covered with a mucous film 

- Presence of mucous layer: volume, pH and composition vary with the menstrual cycle and age

- Characteristics of the drug and partition

- Systemic absorption - avoids first-pass metabolism 

Primarily - Effect on the local muscosa and underlying tissue - the nasal decongestants.

Systemic effect can also be achieved: tissue rich in blood vessels - nicotine 

- Ointments don't need to be sterile, except for ophthalmic use

- Should be free of certain microorganisms and meet requirements for others

Ex: Dermatological ointments: absence of S. Aureus vaginal ointments: absence of yeasts and molds

Contain preservatives: Formulations containing water tend to support microorganisms growth to a greater extent than water free. 

Minimum Fill

Packing, storage, and labeling

-Jars of tubes (plastic or aluminum)

-Applicator tips for vaginal, nasal, rectal, ophthalmic

-Well-closed containers

-Light sensitive materials stored protected from light

*Ophthalmic Ointments:

- Sterile (sterilization of final product vs aseptic processing)

- Limited number of metal particles 

Mineral oil (external phase is oil)

Glycerin (external phase is water) 

Components of the ointment are combined and melted together

You add the components, increased temperature, stir mechanically, and slowly cool.  

Components that cannot be melted are added when the mixture is cooling under stirring.