OINTMENT
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Topical delivery dosage forms
Ointments
Definition and applications
Classification
Hydrocarbon bases
Absorption bases
Water-removable bases
Water-soluble bases
Selection of ointment bases
Preparation of ointments
Some requirements for ointments
Other dosage forms: cream, gel/jelly, paste
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Ointments
Ointments are semi-solid preparations
intended for external use. They are
easily spread.
Typically used as:
Emollients to make skin more pliable
Protective barriers
Vehicles in which to incorporate
medication www.DuloMix.com 3
Ointment bases
Hydrocarbon
Absorption bases
Water-removable bases
Water-soluble bases
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Hydrocarbon bases
. Petrolatum, USP
Yellow petrolatum/petrolatum jelly
Vaseline (Chesebrough-Ponds/Unilever) (vahser-elaion)
Melts at 38-60oC
White petrolatum, USP
Decolored petrolatum,
White petroleum jelly/white vaseline
Yellow ointment, USP
Yellow wax (5%, w/w), petrolatum (95%)
White ointment, USP
White wax/white petrolatum
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Mineral oil
. Liquid petrolatum
Is a mixture of refined liquid saturated
hydrocarbons obtained from petroleum
Levigating agent to incorporate lipiphilic
solids
An excipient in topical formulations where
its emollient properties are exploited as an
ingredient in ointment bases.
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Oleaginous bases
1. Synthetic esters:
glyceryl monostearate, isopropyl
myristate, isopropyl palmitate, butyl
stearate, butyl palmitate, and long-chain
alcohol (cetyl alcohol, stearyl alcohol, PEG)
2. Lanolin derivates:
Lanolin oil, hydrogenated lanolin
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Hydrocarbon bases
Oleaginous bases
Emollient effect: hydrates skin due to sweat
accumulation
Occlusive dressing
Difficult to wash-off/remove
Small amount of water can be incorporated into it
with difficulty and can be protective to water
labile drugs such as tetracycline and bacitracin.
Is greasy and can stain clothing.
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Absorption bases
Those that permit the incorporation of aqueous solution resulting in
he formation of w/o emulsions
–hydrophilic petrolatum, USP
Cholesterol 30 g, Stearyl alcohol 30 g
White wax 80 g, White petrolatum 860 g
–Aquaphor: A gentle healing ointment to help heal dry, cracked
skin
(Petrolatum. Other Ingredients: Mineral Oil, Ceresin, Lanolin
Alcohol, Panthenol, Glycerin, Bisabolol)
Those that are w/o emulsion
Hydrous lanolin: w/o emulsion containing 25% of water
lanolin USP: Anhydrous, contains < 0.25% of water, absorbs
twice its weight in water, also called wool wax, wool fat, or wool
grease, a greasy yellow substance from wool-bearing animals, acts
as a skin ointment, water-proofing wax, and raw material (such as
in shoe polish). www.DuloMix.com 9
Properties of absorption bases
Absorption bases (anhydrous)
Emollient
Occlusive
Absorbs water
Greasy
W/O emulsion
Emollient
Occlusive
Contains water, absorbs additional water
Greasy
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Water-removable bases
Water-washable bases, O/W emulsion
Hydrophilic ointment, USP
Methylparaben 0.25 g
Propylparaben 0.15
SDS 10
Propylene alcohol 120
Stearyl alcohol 250
White petrolatum 250
Water w w w . D u l o3Mi7x.0com 11
Vanishing cream:
o/w emulsion contains la large % of water and
humectant. An excess of stearic acid in the
formula helps to form a thin film when the water
evaporates.
Dermovan:
a hypoallergenic, greaseless emulsion
Unibase:
non-greasy emulsion base has pH close to that of
skin
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Water-washable, easier to
remove
Non/less greasy
Can be diluted with water
Non/less occlusive
Better cosmetic appearance
Better compliance
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Water-soluble bases
PEG ointment, NF
– PEG 3350 400 g, PEG 400 600 g
– Polyethylene glycol 200, 300, 400 (4-8oC),
600 (20- 25oC), 1000, 1450, 3350, 4000, 6000,
8000 and 20000
– Only a small amount of liquid (<5%) can be
incorporated
– If 6-25% of liquid is to be incorporated, 50 g
of the 400 g of PEG 3350 may be replaced
with stearyl alcohol
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EXAMPLE
ZOVIRAX®, (acyclovir), GSK, Ointment 5%
BACTROBAN® SmithKline Beecham Mupirocin
Topical Antibiotic (Each g of ointment contains:
mupirocin 20 mg (2%) in a bland water-soluble
ointment base consisting of PEG 400 and PEG 3 350
(PEG ointment, USP).
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Water-soluble bases
Glyceryl monstearate
polyhdric alcohol esters
wildly used in cosmetic and ointment bases
Cellulose derivatives
Methylcellulose
Cellulose
Hydroxyethyl cellulose
Carbopol/carbomer
synthetic high MW polymers of acrylic acid cross-
linked with either allysucrose or allyl ethers of
pentaerythritol.
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Properties of water-soluble bases
Water soluble and washable
Non-greasy
Non/less occlusive
Lipid free
Synthetic base
Relatively inert
Does not support mold growth
Little hydrolysis, stable
May dehydrate skin and hinder percutaneous absorption.
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Desired release rate of drug
substance
Desirability for topical or
percutaneous absorption
Desirability of occlusion
Stability of drug in ointment
Effect of drug on ointment base
Desire for easy removable
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Incorporation: components are mixed until a
uniform preparation is attained.
— Incorporation of solid:
— Incorporation of liquid:
Fusion: All or some components are combined
by being melted together and cooled with
constant stirring until congealed.
— High melting temperature bases such as
beewax, paraffin, stearyl alcohol, and high Mw
PEG.
Ointments having emulsion bases usually involve
melting and emulsification steps.
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Incorporation
A spatula with a long, broad blade should
be used
Insoluble substances should be powdered
finely in a mortar and mixed with an equal
amount of base until a smooth mixture is
obtained. The rest of the base is added in
increment.
Levigation of powders into small portion
of base is facilitated by the use of
levigating agents.
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Levigating agents:
Mineral oil for oily bases or bases where oil are the
external phase
Glycerin for bases where water is the external phase.
Levigating agent should be equal in volume to the
solid material.
When liquid is added into an ointment, care must be
taken to consider the capacity of the ointment in
accepting the liquid. When it is necessary to add an
aqueous preparation to a hydrophobic base, the solution
should be added into minimal amount of the hydrophilic
base first. The mixture should be then added into the
hydrophobic base.
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Example
Medication order
Sulfur (3-6%, usually)
Salicylic acid, 600 mg
White petrolatum, 30 g
The particle sizes of sulfur and salicylic
acid are reduced separately in a mortar
and then blended together. The powder
mixture is then levigated with the base
using geometric dilution.
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Fusion
Used when the base contains solids that have higher
melting points. Also for solid medications that are
readily soluble in melted bases.
The oil phase should be melted separately, starting with
materials having the highest melting point.
The ingredients in the water phase are combined and
heated separately to temperature equal to above that of
the oil phase
The two phases are them combined. If a w/o system is
desired, the hot aqueous phase is incorporated into the
hot oil phase with agitation.
Volatile materials are added after the melted mixture
cools to desired temperature.
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Requirement for ointments
Microbial content: do not need to be sterile,
but must meet the FDA requirement of the
test for absence of bacteria such as S. areus
and P. aeruginosa for dermatological
products.
Minimum fill:
Packaging, storage, labeling: (label should
include the type of base used)
Additional standards: viscosity, in vitro
release
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Topical dosage form
Ointments
Creams
Pastes
Gels/jellies
Solution
Plasters
Aerosols
Powders
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Cream
Semisolid preparations containing one or
more medicinal agents dissolved in either
an o/w or w/o emulsion or in another type
of water-washable base.
Vanishing cream: o/w with high % of
water and stearic acid.
Cold cream: (an emulsion for softening and
cleansing the skin): w/o, white wax,
spermaceti, almond oil, sodium borate.
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Cream
Typically of low viscosity, two phase system (w/o
or o/w)
Appears “creamy white” due to the scattering of
light.
Traditionally, it is the w/o cold cream
Currently and most commonly, it is the o/w
emulsion.
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Cold cream
w/o emulsion frequently using a borax-beewax
combination as the emulsifying agent and
mineral oil or vegetable oil as the oily phase. A
protective film remains on the skin following the
evaporation of the water. The slow evaporation
of water gives the skin a cooling effect.
To prepare, melt white wax, spermaceti, and
almond oil together, adding host aqueous
solution of sodium borate, and stir until the
mixture is cool.
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A formula
Water, 34.6%,
Borax, 1,
methylparaben, 0.25
Light mineral oil,50%,
synthetic beewax, 13,
Glyceryl monostearate,
1, propylparaben, 0.15.
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Gels and jellies
Jellies are water soluble bases prepared from
natural gums such as tragcanth, pectin,
alginates, boroglycerin, or from synthetic
derivatives of natural substances such as
methylcellulose and NaCMC.
Gels: semisolids consisting of dispersions of
small or large molecules in an aqueous liquid
vehicle rendered jelly-like through the
addition of a gellingw waw.gDuelonMitx..com 32
Single-phase gel:
Carbomers: high Mw water soluble polymers of
acrylic acid cross-linked with allyl ethers of sucrose
or pentaerythritol.
Two-phase system: magma/milk of
magnesia/magnesia magma, a gelatinous precipate
of magnesium hydroxide
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Pastes
Semisolid contains a larger proportion
of solid materials than ointments.
Stiffer than ointment
Good protective barriers
Opague, water impermeable, prevent
dehydration
Good absorbent Lasser’s plain zinc paste
Zinc oxide 25%
Starch, 25%
White petrolatum, 50%
Anthralin in for psoriasis