lecture 5 part 2 Flashcards
**what is pulverization by intervention??
name 2 scenarios in which it would be used
substance is dissolved in solvent and then evaporated easily. as it evaporates, the particles crystallize out of the solution as FINE PARTICLES
- If we want to decrease the particle size of a gummy, sticky substance like coal tar
- for a hard crystalline substance when triturating isn’t working to reduce the particle size - even with a wedgewood mortar
name 2 potential “intervening solvents” that can be used in pulverization by intervention
alcohol or acetone
easily evaporate
explain the levigation method of reducing particle size
used for OINTMENTS or SUSPENSIONS
either triturate in mortar or spatulate on ointment slab with a small amount of liquid in which the solid (drug) is NOT SOLUBLE
explain what the solvent used in levigation should be like
somewhat viscous - like mineral oil or glycerin
name 5 particle size reduction methods
trituration
spatulation
levigation
pulverization by intervention
sieving
**gummy substance not easily triturated - what method of particle size reduction?
pulverization by intervention
**what method is LEAST effective in reducing particle size
spatulation
** a hard crystalline that cannot be triturated - what method of particle size reduction
pulverization by intervention
**reducing particle size for an ointment - what particle size reduction method
levigation
differentiate between bulk powders and divided powders
which is more accurate?
bulk powders - nonpotent – can be dosed with acceptable accuracy by just using a teaspoon or cup as measuring device
divided powders - single doses individually wrapped in cellophane, foil, or paper
DIVIDED POWDERS MORE ACCURATE - PATIENT NOT INVOLVED IN MEASURING DOSE
What are insufflations
extremely fine powders introduced into body cavities
powder placed in inusfflator and bulb is squeezed into the body cavity
as mentioned — EXTREMELY fine - must pass through #100 sieve
true or false
dusting powders are bulk powders
true
name some things that may be used as the inert base for dusting powders
starch
talc
bentonite
magnesium carbonate
kaolin
explain the effect that dusting powders produce
they absorb secretions - have a drying effect which imparts a cooling sensation and relieves congestion
true or false
a single medicinal agent cannot be used as a dusting powder
fals e- it can
can also add inert base
true or false
the particles for dusting powders must be extremely fine
TRUE - 100-200 mesh sieve — to not irritate the skin
***name the order of mixing according to geometric dilution
Drug A 20mg
Drug B 10mg
Drug C 100 mg
1st drug b, then add drug a 10mg at a time
after all drug a added, add equal amount of drug c
smallest - largest
geometric dilution is used for….
incorporating small amounts of potent drugs
***name the 4 basic types of powder papers available
vegetable parchment
white bond
glassine
waxed
explain the properties of waxed paper***
TRANSPARENT and WATERPROOF
explain the properties of white bond**
opaque with NO moisture resistant properties
**explain the properties of vegetable parchment
thin, semi-opaque with moisture resistant properties
**explain the properties of glassine
glazed
transparent
moisture resistant
which type of powder paper should we avoid for large quantities**
vegetable parchment because its thin
if the powder contains hygroscopic or deliquescent materials, which powder paper should be used**
waxed paper - or any WATERPROOF PAPER
powders that contain volatile components should be wrapped in which paper
waxed or glassine
powders that do NOT have volatile components and do NOT have ingredients adversely affected by air or moisture are usually wrapped with what
white bond
***which powder paper has NO moisture resistant properties
white bond
***explain what hygroscopic and deliquescent substances are
hydroscopic - absorbs moisture from air
deliquescent - hygroscopic powder that is so hygroscopic that when it absorbs moisture from the air that it partially or wholly dissolves in it – becomes liquid
______ dosage form is preferred for deliquescent drugs
liquid
what can be added to the formulation of a hygroscopic or deliquescent substance
give 2 examples
a water-insoluble powder that will ADBSORB the water attracted by the hygroscopic/deliquescent substance
light magnesium oxide (small qty - laxative) or talc
what container must deliquescent or hygroscopic powders be dispensed in??
if divided powders, they should be wrapped in what??***
TIGHT CONTAINERS
if divided - double wrap in wax paper or seal in plastic or foil. put the packets in tight container
a _________ may be incorporated into the container of a hygroscopic or deliquescent powder
dessicant
explain what a eutectic mixture is**
mixture of 2 or more components what LIQUEFY when mixed together
they each lower the melting point of the other below room temp - causing liquefication
what is a method to overcome the issue of eutectic mictures ( not the best)
add an inert diluent
ex - mg carbonate, light mg oxide, kaolin, starch, bentonite
what is the BEST method to overcome the issue of eutectic mixtures
dispensed in separate packets and the patient will mix them right before they take it
give an example of a eutectic mixture
menthol and cmaphor
explain what efllorescent powders are***
crystalline substances that contain water of crystallization or hydration, and RELEASE THE WATER into the environment
powdered substance as a result may become damp and like paste
aside form turning into a paste, what is another issue when efflorescent powders release water
the MW changes
given weight of the powder no longer contains the same amount of drug
name 2 methods to overcome the issue of efflorescent powders
- store in TIGHT container
- use anyhrous form - no water to lose!!
“if you triturate long enough, what can release making the powder pasty and wet”
what is this?
an efflorescnet powder
water RELEASED
for efflorescent powders is it preferred to have granules or powders and why
GRANULES
less surface area. powders will fizz way too much
will dissolve more slowly and have more controlled reaction
aside from menthol and camphor, name another eutectic mixture***
benzocaine, salicylic acid, and camphor
what container is camphor stored in and why
sublimes to air at room temp (evaporates)
true or false
*****granules flow AND compress better than powders
true
which have larger particle size - powders or granules
granules
which segregate more and why - powders or granules
powders - have greater surface area. less stable to moisture and O2
effervescence hekps what
to mask the taste of the drug
4 components in effervescent granules
API
sodium bicrabonate
citric monohydrate
tartaric acid
in effervescent granules, why is citric acid monohydrate not used alone? why is tartaric acid not used alone?
citric acid not used alone bc it’s too sticky and won’t easily granulate
in contrast, tartaric acid is too friable and crumbly
to make better consistency, both used together along with API and sodium bicarbonate
effervescent granules contain 2 ___ and a __-
2 acids and a base
*** ration of citric acid monohydrate to tartaric acid in preparing effervescent granules
1:2 w/w
** which type of powder paper best protects a hygroscopic powder
waxed paper
**a VERY FINE POWDER is defined as
completely passes through 80 sieve
divided powders may be dispensed in….
individual dose packets
how to determine highest flowability
whichever has smallest angle of repose
which has faster GI absorption - granules or powders***
POWDERS - related to dissolution
what will happen if you triturate efflorescent powder
will release water and becomes damp and pasty
which particle size reduciton method is insoluble drug pressed against ointment slab
levigation
