1.2 Ointment Flashcards
Definition of ointment
A viscous, homogenous, semisolid preparation intended for external as well as topical application on a variety of body surfaces
Where is the application of ointment ?
Skin and the mucous membranes
Uses of ointments
Emollients or for the application of active ingredients to the skin for protective, therapeutic, or prophylactic purposes
3 classifications of ointments
- Based on their composition and physical characteristics related to bases
-oleaginous bases
-absorption bases
-water-removable bases
-water-soluble bases - Based on water solubility
-hydrophobic ointment
-hydrophilic ointment
-water-emulsifying ointment - Based on therapeutic activity and penetration to skin
-epidermic ointment
-endodermic ointment
-diadermic ointment
4 Types of bases
-water-soluble base
-emulsion base
-absorption base
-oleaginous base
What are the properties of water-soluble base ?
-absorb and dissolve in water
-washable
-non-greasy
-Don’t deteriorate
-support mold growth
What are the advantages of water-soluble base ?
-wide range of compatibility
-non-irritating
-don’t support microbial growth
-easily washed off
Disadvantages of water-soluble base ?
gradual discoloration with certain drugs
Give the examples of emulsion base properties
-miscible with water
-contain o/w emulgents
-can be easily removed
Based on the nature surfactant present, emulsion bases are divided by three and give examples :
-anionic emulsion bases (eg: hydrophilic and emulsifying ointment)
-cationic emulsion bases (eg: cetrimide emulsifying ointment)
-non-ionic emulsion bases (eg: cetomacrogol emulsifying wax)
What are the advantages and disadvantages of emulsion base ?
Advantages:
-washable
-non-greasy
Disadvantages:
-subject to water loss if o/w
-greasy
-unwashable
-subject to mopd growth
Properties of absorption base ?
-non-emulsified (absorb water and aqueous solutions to produce w/o emulsions)
-w/o emulsions ( absorbing more water)
Advantages and disadvantages of absorption base ?
Advantages:
-highly compatible
-relatively stable to heat
-can be used in anhydrous form
Disadvantages:
-greasy
-less occlusive
What are the properties of oleaginous base ?
-anhydrous
-don’t absorb water readily
-insoluble in water
-not washable
Advantages and disadvantages of oleaginous base ?
Advantages:
-highly compatible
-occlusive
-Good emollients
Disadvantages:
-difficult to remove from skin and clothing
Selection of appropriate base based on physicochemical factors
-easy removable
-release rate of drug substance
-stability of drug in ointment
-topical or percutaneous absorption
-effect of drug on ointment base
Selection of appropriate base based on patient factors
-if a patient’s skin is dry, occlusive ointment base that retains moisture is recommended
Properties that affect the choice of an ointment base
-stability
-penetrability
-solvent property
-irritant effects
-ease of application and removal
What are the requirements of ointments ?
- Microbial content
-Don’t need to be sterile
-meet FDA requirements of the test absence of bacteria “s.areus/p.aeruginosa” - Minimum fill
-packaging
-storage
-labelling
-additional: viscosity
Method of preparing ointments
-trituration/ incorporation
-fusion
-chemical reaction
-emulsification
Explain the trituration method
-a finely insoluble medicaments distributed by grinding with a small amount of base
-fine powders are placed in a mortar or on a ointment
-gently mixed with base until mixture is homogenous
-if liquid ingredients present, before incorporate liquid ingredients, a portion of base is placed on the ointment slabbed a recess made to hold the liquid
-ointment is transferred to the container
Explain fusion method
-ointment base contains a number of solid ingredients like white bees wax, acetyl alcohol, steady alcohol and hard paraffin
-all or some of the components of ointment combined and melted together and cooled with constant stirring until congealed
-heat-liable Substances and any volatile components are added last when the temperature of the mixture is low enough
How do ointments packaged ?
-suitable plastic tubes or syringes
-ointment jars
Storage and containers for ointments
-store in a cool place but don’t freeze
-shelf life 4 weeks
-screw-capped amber glass
-plastic pots
-collapsible metal tubes
What is a levitating agent ?
-Mineral oil for oily bases or bases wher3 oil are external phase. -Levigating agent should be equal in volume to the solid material
