Chapter 7 Flashcards
ointments are ______ dosage forms
semi solid
the most commonly used semi solid dosage forms are
ointments, creams, pastes, gels, jellies and suppositories
semi solid preparations are intended for ______ application like the __________
external, skin
preparations that do not contain therapeutic agents are used for their _______ effects such as ________
physical
protectants, emollients, lubricants
what are the uses of semi solid dosage forms?
to protect the skin/mucous membrane from chemical/physical irritants in the environment and to permit rejuvenation of the tissue
to provide hydration of the skin
to provide an emollient effect
to provide a vehicle for applying a medication either for local or systemic effect
what is an example of a semi solid dosage form that provides a vehicle for local effect?
application of a topical antibiotic
what is an example of a semi solid dosage form that provides a vehicle for systemic effect?
application of nitroglycerin ointment for treating angina
what factors need to be considered when compounding semi solid preparations?
choosing the proper base for the preparation
calculating quantities needed
choosing proper equipment needed
incorporating solids into preparation base
using proper technique to incorporate liquids
What are the 6 factors that determine the type of base that must be selected to prepare an ointment?
- desirability of percutaneous absorption of drug
- the action or effect of product desired
- base as vehicle for a medicinal substance
- patient factors
- the area of application
- specified ointment base
What factors should be considered if the ointment base is being used as a vehicle for a medicinal substance?
- desired drug release and bioavailability of the incorporated medication
- short term as well as long term stability of the medication in the ointment base
- compatibility of the medication with the ointment base
- effect of drug on the consistency of the ointment base
a specific ointment base can be used due to ______ or ____________ to substitute the prescribed base with a more desirable base
compatibility or stability reasons
T or F: before substituting a base, the prescriber does not need to be consulted
False. They do.
What are the desirable properties of an ointment base?
meets USP standards for microbial content
stable chemically/physically
nontoxic, non sensitizing, nonirritating, nonreactive
compatible with a wide variety of drugs and auxiliary agents
easy to apply to affected area, and remain in contact with the site of application until desired, and then be able to be easily removed
maintain its desired consistency after the drug has been incorporated into the base
free from objectionable odor, aesthetically appealing and non greasy
the absence of certain microbes such as _____ and ______ because of their capacity to infect skin which is already probably compromised
stap aureus
pseudomonas aeruginosa
what are the four general classes of ointment bases?
hydrocarbon
absorption
water removable
water soluble
what is another name for hydrocarbon bases?
oleaginous bases
what are the two types of absorption bases?
anhydrous - containing not more than 0.25% water / absorb water/ form W/O emulsions
W/O emulsions to begin with and capable of accepting small amounts of water without losing physical characteristic
Whats another name for water removable bases?
oil in water emulsions
what are some characteristics of hydrocarbon bases?
insoluble in water
do not contain water
will not absorb water
not water washable
greasy
emollient and occlusive
what are some examples of hydrocarbon bases?
plastibase
vaseline
white ointment
white petrolatum
yellow ointment
yellow petrolatum
what are some characteristics of absorption bases (anhydrous) ?
insoluble in water
can absorb water
not water washable
greasy
emollient and occlusive
what is the difference between hydrocarbon bases and absorption bases?
hydrocarbon bases cannot absorb water and absorption bases (anhydrous) can
what are some examples of absorption bases (anhydrous)?
aquabase
aquaphor
hydrophilic petrolatum
lanolin
polysorb
what are some characteristics of absorption bases (w/o emulsions)?
insoluble in water
not water washable
contain water
can absorb small amount of water
greasy
emollient and occlusive
what are some examples of absorption bases (w/o)?
cold cream
eucerin
hydrocream
lanolin, hydrous
nivea
rose water ointment
what are some characteristics of water removable bases (o/w)?
insoluble in water
water washable
contain water
can absorb water
non occlusive
non greasy
what are some examples of water removable bases?
dermabase
hydrophilic ointment
unibase
vanishing cream
velvachol
what are some characteristics of water soluble bases?
water soluble
water washable
can absorb small amount of water
anhydrous or hydrous
non occlusive
non greasy
what are some examples of water soluble bases?
PEG
when preparing ointments and determining the quantities needed pharmacist like to __________
calculate slightly higher to compensate for loss during compounding and transferring preparation
what are the two basic pieces of equipment used for compounding and ointment preparation?
ointment slab and pad
spatulas
what are ointment pads made of?
waxed or parchment paper
what are the benefits of using an ointment pad?
minimizes cleanup
what is preferred, an ointment slab or pad? why?
slab, less loss of product
What are large metal spatulas used for compared to small metal spatulas?
large - levigation, spatulation, incorporation of solid and liquid ingredients in to the ointment base
small - removing product from large and transferring
when are black rubber or plastic spatulas used?
special purpose - used when ingredients react with metal
which ingredients react with metal spatulas?
iodine, salicyclic acid
black rubber or plastic spatulas are not for general use in compounding ointments becaus
they do not have proper combination of flexibility and strength to give adequate shear and mixing
what are important factors to consider when incorporating solids into an ointment base?
choice of drug form
levigation
solvent
What is the most preferred drug form?
a fine powder
What is levigation?
levigation is the process of incorporating a solid by triturating it in a mortar or spatulating it on an ointment slab with a small amount of liquid
the levigating agent should be
a liquid, somewhat viscous, low surface tension to improve ease of wetting the solid
the solid during levigation should be
NOT soluble in the levigating agent
what are the commonly used levigating agents?
mineral oil
glycerin
propylene glycol
peg 400
cottonseed oil
castor oil
polysorbate 80
what is another name for polysorbate 80
tween 80
which levigating agent can be a substitute for mineral oil when vegetable oil is preffered?
cottonseed oil
which levigating agent is used for coal tar/when a surfactant is needed?
tween 80
which levigating agent may be incompatible with some w/o emulsion bases?
tween 80
which levigating agent is used with oleaginous bases, absorption bases, and w/o emulsion bases?
mineral oil
mineral oil is miscible with fixed oils except
castor oil
mineral oil is immiscible with
alcohol, PEG 400, glycerin, propylene glycol, and water
glycerin is a levigating agent used with
o/w emulsion bases, water soluble bases, ichthanmol
glycerin is miscible with
alcohol, PEG 400, glycerin, propylene glycol and water
glycerin is immiscible with
mineral oil and fixed oil
propylene glycol is a levigatating agent used with
o/w emulsion bases, water soluble bases
what is propylene glycol miscible with?
alcohol, peg 400, glycerin, propylene glycol and water
propylene glycol is immiscible with
mineral and fixed oils
hydrocarbon bases are mainly used for
their emollient effect
which base is retained on the skin for prolonged periods of time?
hydrocarbon bases
water free preparations are which bases?
hydrocarbon
what kind of emulsion is rose water ointment?
semisolid white w/o emulsion
T or F Levigating agents are usually chosen to be chemically similar to ointment base
T
which levigating agent is generally chosen for water removable and water soluble bases?
glycerin - miscible with water
which levigating agent is generally chosen for oil bases?
mineral oil
what levigating agent is reccomended with peruvian balsam? why?
castor oil
contains sulfur
T or F: Hydrocarbon bases are easy to wash off
F, difficult to wash off
what is the main drawback of hydrocarbon bases?
they do not absorb water or aqueous solutions
limited amount of alcoholic solutions absorb
what base is known as simple ointment?
yellow ointment
why does yellow ointment have a slightly greater viscosity than petrolatum?
the inclusion of yellow wax, makes it stiffer
a synthetic counterpart of petrolatum is
plastibase
what is the advantage of plastibase
wide spectrum of temperature range that has little effect on altering base consistency
hydrophilic bases that have the ability to absorb added water
absorption bases
______ result in the formation of w/o emulsions
anhydrous bases
what is the main ingredient in anhydrous absorption bases?
cholesterol
refined wool fat is also known as
anhydrous lanolin
hydrophilic petrolatum is made of
cholesterol, stearyl alcohol, white wax, white petrolatum
aluminum acetate solution is also known as
burrows solution
burrows solution is incompatible with
alkalis, carbonate and borax
cold cream and rose oil share the same formula except
cold cream has mineral oil instead of almond oil
cold cream is
a white semi solid w/o emulsionn
what cannot be used with cold cream
salicylic acid
iodine is incompatible with
reducing agents, volatile oils, alkaloids, and strong oxidizing agents
T or F alcohol does not mix well with hydrocarbon bases
T
