Semisolid Dose Forms Flashcards
what are 3 dose forms that are considered semisolid dose forms?
ointments
creams
gels
what are these dose forms mainly intended for? what other uses do they have?
topical application
ophthalmic, nasal, vaginal, or rectal use
what must you consider when making topical products?
systemic drug absorption if the patient is pregnant or nursing
why do you have to consider systemic drug absorption for pregnant/nursing women?
drugs can enter the fetal blood supply and breast milk and be transferred to the fetus/nursing infant
what are ointments?
semisolid preparations intended for external application to the skin or mucous membranes and they may or may not be medicated
what are non-medicated ointments used for?
their protective, emollient or lubricating activity
what are ointment bases used for?
for their physical effects or as vehicles in medicated ointments
what are the 4 groups of ointment bases?
oleaginous bases
absorption bases
water-removable bases
water-soluble bases
what is the use of oleaginous bases?
have an emollient effect on the skin, protect against the escape of moisture and are effective as occlusive dressings
they remain on the skin for a long time
why are oleaginous bases hard to wash off?
they are immiscible in water
can you incorporate aqueous or water solutions with oleaginous bases?
ye, but only in small quantities and with difficulty
what levigating agent could be used to incorporate powders into oleaginous bases?
liquid petrolatum (mineral oil)
what are 2 examples of oleaginous bases?
white petrolatum USP
vaseline
what are absorption bases?
essentially water in oil emulsions
what are the two types of absorption bases? give an example of each
1) those that allow incorporation of water to form an emulsion (w/o)
ex: hydrophilic petrolatum
2) those that are already emulsions (w/o)
ex: lanolin
what is the use of absorption bases? (2pts)
provide a way of incorporating small volumes of aqueous solutions into hydrocarbon (oleaginous) bases
can be used as emollients, though not as occlusive as oleaginous bases
how do you incorporate aqueous solution into oleaginous bases?
incorporate the aqueous solution into the absorption base, and then incorporate this mixture into the hydrocarbon base
what are 2 examples of absorption bases?
cold cream
Nivea
what are water-removable bases?
essentially oil in water emulsions, easily removed from the skin by washing and can be diluted with aqueous solutions
what are some examples of water-removable bases?
hydrophilic ointment USP
dermabase
unibase
what makes water-soluble bases different from the other ointment bases?
do not contain and oleaginous components so they are completely water washable and often referred to as greaseless
what are water-soluble bases used for? why?
incorporation of solid materials as the addition of water/aqueous solutions will dissolve then and they lose their semisolid consistency
what is an example of a water-soluble base?
polyethylene glycol ointment NF
what are the considerations for choosing an appropriate base? (11pts)
1) water content
2) water affinity
3) spreadability
4) washability
5) drug incorporation
6) drug release
7) occlusive?
8) absorbed topically or percutaneous
9) stability of drug in base
10) effects of drug on product consistency
11) site of application
what is the water content for each of the ointment bases?
ole - anhydrous
abs - hydrous
rem - hydrous
sol - anhydrous/hydrous
what is the water affinity for each of the ointment bases?
ole - hydrophobic
abs - intermediate
rem - hydrophilic
sol - hydrophilic
what is the spreadability for each of the ointment bases?
ole - difficult
abs - moderate
rem - easy
sol - moderate/easy
what is the washability for each of the ointment bases?
ole - no washability
abs - poor washability
rem - washable
sol - washable
what is the drug incorporation for each of the ointment bases?
ole - solids/oils
abs - solids/oils/some aqueous
rem - solids/aqueous
sol - solids/aqueous
what is the drug release for each of the ointment bases?
ole - poor
abs - intermediate
rem - fair
sol - good
which of the ointment bases show occlusive properties?
oleaginous base
absorption base (intermediate)
water-removable/water-soluble are not occlusive
what are the two main methods of preparing an ointment?
incorporation
fusion
which method is more commonly used for ointment preparation: trituration or spatulation?
spatulation
what must you do with solids before you incorporate them into the base? why?
reduce particle size so the product will not be gritty
if you were to levigate the solid that is to be added to the base, what are some requirements for the levigating agent?
chemically/physically compatible with the drug and base
what levigating agent is best used for bases where the external phase is oil? external phase is water?
oil - mineral oil
water - glycerin
what method to reduce particle size would you use for camphor (gummy material)?
pulverization by intervention
what is pulverization by intervention?
the material is dissolved in a solvent (like alcohol) and spread out on the slab and allowed to dry as a thin film. you can then work it into other ingredients by spatulation
what tools do you use for preparing an ointment on a glass slab?
broad-bladed stainless steel spatula and a smaller version to periodically remove accumulated material from the larger
when would you use plastic spatulas instead of metal ones?
when a component may react with the metal (ex iodine)
what would you use for incorporation of liquids/solutions of drugs: a mortar/pestle or a glass slab? why?
mortar and pestle because the liquid is more captive than on a glass slab
what two things need to be taken into consideration when mixing the ointment base with a liquid?
1) base is compatible with the liquid
2) make sure the volume added is not too large, causing the product to become too semi-liquid
how does the fusion method work?
some or all of the components are melted together and cooled with stirring until congealed
what product components work for fusion and not for incorporation?
products containing:
beeswax
stearyl alcohol
high MW polyethylene glycols (PEGs)
In what order are the materials melted?
start with the material of highest melting point, then move to the material with the next highest melting point
why do we add materials in order based on MP?
a lower temp is sufficient to achieve fusion since the first melted components exert a solvent effect on the successive materials
what is usually the highest temp needed for fusion?
70°C
what kind of substances must you treat with caution when using the fusion method?
volatile and heat liable substances
why do you use a water bath for fusion?
to avoid excessive heating
what should you do if you’re fusing an aqueous and oleaginous mixture?
both should be heated separately then combined with stirring
add the aqueous to the oleaginous
what are creams?
semisolid preparations containing medication dispersed in an emulsion base and after application, the water evaporates leaving a film of the oleaginous components
what makes creams more cosmetically acceptable?
less greasy and easier to spread/remove
when is an ointment preferable over a cream?
occlusive action is preferred and the skin is dry/scaly
when do you use creams rather than ointments?
when the skin is weeping or there are exudates
creams tend to be drying
what 2 forms can lotions be found in? what are they typically formulated as?
fine suspensions
emulsions
formulated as semi-liquid creams
what are pastes?
thick, stiff preparations usually with a high content of solid material often to the order of 25%
what are pastes used for?
absorb serous secretions and as protectants
what is an example of a paste being used as a protectant?
zinc oxide paste used to treat diaper rash
what are plasters/glycerogelatins?
archaic products designed for long-term application to the skin
what is the difference between plasters and glycerogelatins?
plasters - have backing of paper/fabric
glycerogelatins - plastic masses which are heated before use to melt them then paint onto skin where they solidify, then covered with a bandage
give an example of a plaster
corn plaster
contains salicylic acid that is used for corn removal
what have glycerogelatins been used to treat?
varicose ulcers
what are topical dermatological products usually packaged in?
jars or tubes
what are rectal, vaginal, and ophthalmic products usually packaged in?
tubes
describe what ointment jars typically look like/are made of
made of glass or plastic
wide mouths with screw caps
what are tubes typically made of?
aluminum (lined with plastic)
plastic
what is the typical size range for ointment jars?
15-500mL
what is the typical size range for tubes?
3-120mL
what is included with tubes for rectal/vaginal use?
applicator tip
how are the jars filled?
air entrapment is avoided
product does not touch lid
pack weighted product into jar using spatula (unless made via fusion, then pour)
how do you package tubes?
weighed material may be rolled in a tube of suitable paper, the roll is inserted into the open end of the tube, then the paper is withdrawn while flattening holding down the edge of the tube
crimp end of tube to seal it
