ACT 3& 4 Flashcards
(31 cards)
are semisolid preparations
intended for application to the skin.
They generally contain a larger proportion of solid material (such as 25%) than ointments and therefore are stiffer
Pastes
However, when a levigating agent is
to be used to render the powdered component smooth, a portion of
the base is often used rather than a
liquid, which would soften the paste.
NOTES RA
Preparation of Paste
-Direct mixing
-Use of heat
Use today:
Zinc Oxide Paste (Lassar’s Plain Zinc Paste)
semi-solid preparation intended for
topical application
Ointments
APPLICATION OF OINTMENTS
- Skin
- Surface of the eye
- Nasally
- Vaginally
- Rectally
The unmedicated ones are used for their
physical effects as
protectants or lubricants
-delivered into the skin; treating dermal
disorders with the skin as the target organ
Local effects
- consideration for pregnant women and
nursing mothers
Example: *Transdermal product**
Systemic effects
A __________________ is designed to deliver
drug into the skin in treating dermal disorders, with the skin as the target organ.
topical dermatological product
A ________________ is designed to deliver drugs through the skin (percutaneous absorption) to the general circulation
for systemic effects, with the skin not being the target organ.
transdermal product
semisolid preparations for external application to the skin or mucous membranes
-may be medicated or not
OINMENTS
-used for physical effects (protectant,
emollients, lubricants)
Unmedicated ointments
-used for physical effects or as vehicles for medicated ointments
Ointment base
OINTMENT BASES
a. Oleaginous bases
b. Absorption bases
c. Water-removable bases
d. Water-soluble bases
- termed as hydrocarbon bases
- emollient effect
- protect against the escape of moisture
- effective as occlusive dressing
- remain on the skin for long periods without drying out
- immiscible with water (difficult to wash off)
- water and aqueous prep may be
incorporated but only in small amounts and with some difficulty
-Levigation is commonly used in small-scale
preparation of ointments and suspensions
to reduce the particle size and grittiness of the added powders.
OLEAGINOUS BASES
OLEAGINOUS BASES
Example:
- Petrolatum
- white petrolatum,
- white ointment
- yellow ointment
In oleaginous bases, when powdered substances are to be incorporated into hydrocarbon bases, ____________ (mineral oil) may be used as the levigating agent
liquid petrolatum
is commonly used in small-scale
preparation of ointments and suspensions
to reduce the particle size and grittiness of
the added powders.
Levigation
These bases may be used as
emollients, although they do not
provide the degree of occlusion
afforded by the oleaginous bases.
-are not easily removed from the skin with water washing, because the external phase of the emulsion is oleaginous
Absorption bases
- those that permit the incorporation of
aqueous solutions resulting in the
formation of water in oil (W/O) emulsions
(e.g., hydrophilic petrolatum)
-those that are W/O emulsions (syn:
emulsion bases) that permit the
incorporation of additional quantities of aqueous solutions
(e.g., lanolin)
-This is accomplished by incorporating the
aqueous solution into the absorption base
and then incorporating this mixture into the hydrocarbon base.
-are useful as pharmaceutical adjuncts to incorporate small volumes of aqueous solutions into hydrocarbon bases.
Absorption 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. - They may be diluted with water or aqueous solutions.
- They can absorb serous discharges.
Hydrophilic Ointment, USP, is an
example of this type of base.
WATER-REMOVABLE BASES
do not contain oleaginous components
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 (PEG) ointment, NF, is the prototype example of this base.
Water-soluble bases
SELECTION OF THE APPROPRIATE BASE
- Desirability of topical or percutaneous drug absorption.
- Desired release rate of the drug substance from the ointment 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.
-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
