Chapter 6 - Powders and Granules - Part 2 Flashcards
explain how pulverization by intervention works
use a solvent (WETTING LIQUID) and dissolve the powder. this wetting liquid should be easily removed at the end of the process.
the solid dissolves in this volatile solvent and evaporates. the powder then recrystallizes to obtain FINE PARTICLES (amorphous form)
true or false
in both levigation and pulverization by intervention, the liquid added remains in the product
FALSE
levigation – is included in product
pulverization by intervention - liquid is NOT INCLUDED. it is volatile and evaporates
for pulverization by intervention, what type of mortar should be used and why
GLASS MORTAR
wedgewood is too porous and the aromatic oil will be absorbed into the pores
true or false
the liquid added in pulverization by intervention is a SOLVENT to the drug and the liquid added in levigation is a NONSOLVENT to the drug
TRUE
Explain the trituration and sieving method of the small scale comminution of drugs
substance reduced to a very fine powder by the continues attribution of the particles between the hard surfaces of pestle and sides/bottom by wedgewood mortar
sieving is a means of separating and measuring particle size (as mentioned).
however, some particles are indeed broken down in size as they are forced through the screen of the sieve
THIS METHOD IS NOT NORMALLY USED AND THE OTHER 3 ARE
give an example of a substance that needs pulverization by intervention
camphor
name 6 methods of blending/mixing powders
what is the 1st choice
spatulation
trituration
sifting
tumbling
random mixing and ordered mixing
mechanical (vs manual)
spatulation is 1st choice
what is spatulation NOT suitable for
the homogeneous blending of POTENT materials
this is bc the amount is so small
(bc potent) and spatulation would not work
small amount blending
spatulation
true or false
the spatulation method involves a lot of compression and compaction of the materials
FALSE
very little compression and compaction
as mentioned, spatulation is NOT suitable for the homogeneous blending of potent materials.
what IS spatulation suitable for?
suitable for EUTETIC MIXTURES
name 6 ingredients that will form eutetic mixtures
phenol
camphor
menthol
thymol
aspirin
phenyl salicylate
explain the force that should be applied in spatulation
don’t want a strong force because this will further reduce the particle size, which is not what we want – we just want to gently mix the materials
true or false
trituration involves both comminution and mixing
true
spatulation is just mixing
what kind of mortar is preferred for trituration
wedgewood is preferred bc it is desired to breakdown the particle size
what is the preferred method for blending/mixing powders for POTENT drugs?
what about nonpotent?
for potent drugs - trituration bc mixes more closely and intimately than spatulation
for non potent drugs - spatulation
what method of manually blending/mixing powders uses geometric dilution
trituration
explain geometric dilution
when is it used?
used when blending 2 or more powder ingredients of unequal quantities
helps to ensure that small quantities of ingredients (inc potent drugs) are uniformly distributed throughout the powder mixture
gives more intimate mixing – method of choice for potent drugs
ex: 1g of excipents and 100mg of API
1st, mix 100 mg of each together and then add another 200mg of excipients …etc until all is mixed
in geometric dilution, what should be done when quantities to be mixed are
100mg
200mg
300mg
1000mg
start from the smallest and add more ingredients.
once all mixed add the largest quantity and mix all together
sifting and tumbling methods of blending/mixing powders are mainly used for what
chemo reagants
random mixing and ordered mixing:
give a scenario in which random mixing should be used and when ordered mixing should be used instead
random mixing is used to get a homogeneous mixture for a NONPOTENT DRUG
need ORDERED MIXING for potent drugs
when is mechanical blending/mixing powders used
in manufacturing
name 3 equipment that can be used in MECHANICAL blending/mixing powders
V-Blender
Triple-V type
Turbula mixer
name 5 special considerations when preparing pharmaceutical powders
which 3 are most relevant
eutetics
hygroscopic and deliquescent powders
efflorescent powders
explosive mixtures
incorporation of liquids
1st 3 - eutetics/hygroscopic and deliquescent powders/efflorescent powders are the most important