Lab 8 Flashcards
what USP chapter described lotions?
1151
USP chapter 1151 describes lotions as….
emulsified dosage form that is generally intended for external application on the skin
true or false
lotions have similar properties to creams
true
however, lotions are more fluid and pourable
which are more spreadable - lotions or creams? which can be applied to a large skin area?
lotions for both
what kind of emulsions are lotions?
O/W
they contain a large amount of water
true or false
lotions do not require preservatives
false - they do
they are O/W emulsions and thus contain a lot of free water
true or false
calamine lotion is a lotion
false
it’s technically not the USP definition of a lotion.
it is a topical suspension and not a lotion
what USP chapter describes creams?
USP 1151
USP chapter 1151 describes creams as…
emulsified dosage forms for external application
contain more than 20% water and volatiles
contain LESS than 50% hydrocarbons, waxes, and fatty alcohols
creams are relatively _____ and have a ____ consistency
relatively soft and have a spreadable consistency
where are creams intended for?
the skin and the mucous membranes
what are the different types of creams?
washable and non-washable creams
washable = O/W emulsions
nonwashable = W/O emulsion
classify surfactants
anionic
cationic
nonionic
amphoteric
name some anionic surfactants
sodium oleate (soap)
SLS
natural sources = soaps
the hydrophilic head is ANIONIC
Give an example of a cationic surfactant
benzalkonium chloride
hydrophilic head is cationic
give an example of a nonionic surfactant
TWEEN 20 (polyethylene glycol sorbitan monolaurate)
hydrophilic head has NO CHARGE
Explain the structure of an amphoteric surfactant
the hydrophilic head has both anionic and cationic charges
the HYDRATED stratum corneum has an affinity for what kind of drugs?
both hydrophilic and lipophilic
name 3 factors that affect the release of the drug from the ointment base
drug properties
the ointment base
the skin type
explain how the drug properties can affect its release from the ointment base
the partition coefficient of the drug
the concentration of the drug in the product
most drugs are hydrophilic or hydrophobic in nature??
hydrophobic
true or false
hydrophobic drugs are generally released faster from a hydrophobic base as compared to a hydrophilic base
FALSE
hydrophobic drug is released faster from a hydrophilic base
hydrophobic drugs will be released faster from which type of base?
-O/W emulsion
-oleaginous base
O/W emulsion
will hydrophobic drugs be released relatively quickly from a water miscible base?
yes
