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
explain what explosive mixtures are and give example
react violently when mixed together
ie: oxidizing agents and reducing agents
iodine, nitrates, etc
why is the incorporation of liquids into pharmaceutical powder a special consideration
the liquid may be adsorbed onto an inter material like lactose or starch
therefore, the liquid should be geometrically introduced into the bulk powder
explain what eutetics is
PAIR of solids that tend to liquefy when they come in contact with each other.
this is bc one solid acts as an impurity for the other and THE MELTING POINT OF EACH SOLID IS LOWERED
the melting point of either solid ingredient is near or below room temp, and the solids become damp/pasty/liquid (depending on amt of melting point lowering)
When given a list of potential eutectic substances, what is a good way to determine if a random combination will form a eutectic mixture or not
2 substances with a high MP (like acetaminophen and aspirin) most likely WONT form a eutectic mixture bc the melting point won’t decrease significantly
however, menthol has a very low melting point and camphor has very high so they WILL form a eutectic mixture bc melting point will be lower than 25 degrees c
true or false
thymol and camphor can form a eutectic mixture
true
Resorcinol and ______ can form a eutectic mixture
chloral hydrate
if 2 liquids are mixed together and the resultant melting point of the solids is much greater than room temp, does this pose any problem?
NO
the eutetic mixture results in a liquid much faster when _____ are combined
low melting point components are combined
explain the proper method to handle eutectics
first make the eutectic, and then absorb that liquid/paste onto an inert, finely divided solid with a HIGH melting point
or triturate the potential eutectic formers separately with an inert ingredient, and then mix the powders together through GENTLE spatulation or tumbling
as mentioned, there are 2 potential methods for handling eutectics.
which would be more suitable for menthol: camphor and why
do NOT use the separate trituration method if we already have desired particle size. the particle size of camphor cannot be reduced through this method
therefore, for menthol:camphor, the liquid eutectic should be allowed to form and then absorbed onto an inert, high-melting, finely divided solid
as mentioned, there are 2 different methods to handle eutectics.
both involve adding an ingredient. explain what this ingredient should be
in the method for allowing the eutectic to form, a LOW DENSITY, HIGH MELTING POINT absorbing solid should be used, in order to use a MINIMUM WEIGHT of the absorbing solid
FOR EXAMPLE: light magnesium oxide, kaolin, lactose, starch
in the method for triturating the potential eutectics separately, a low density inert ingredient should be used so that the minimum weight is used
name the 4 potential high melting point, low density absorbing solids that can be added to a eutectic mixture that has already formed in order to absorb it
light magnesium oxide
kaolin
lactose
starch
what are hygroscopic powders?
solids that absorb moisture from the air
when are hygroscopic powders referred to as deliquescent powders?
when they are able to absorb enough moisture from the air so that they partly or wholly dissolve in it (liquefy)
deliquescent powders are preferred in what dosage form?
liquid dosage form (solution or suspension)
as mentioned, deliquescent powders are preferred in the liquid dosage form.
if the prescriber denies this, what must be done
the powder must be dispensed in a form that is acceptable to the patient.
for instance….
add a water INSOLUBLE powder ingredient to prevent/minimize water absorption
dispense in a TIGHT CONTAINER and tell pt to keep tightly closed and stored in low humidity
should be double wrapped in wax paper or sealed in plastic or foil, and the packets put in tight containers (FOR DIVIDED POWDER DOSAGE FORM)
In dispensing deliquescent powders, a water insoluble powder ingredient can be added to prevent/minimize water absorption.
what ingredient can be added and why
light magnesium oxide in a quantity used that will NOT produce a laxative effect
preferred over heavy magnesium oxide – want to keep light weight
true or false
hygroscopic substances will absorb water but not liquefy, while deliquescent substances will absorb water but will liquefy
true
name 2 popular hygroscopic substances
ephedrine sulfate
phenobarbital sulfate
name 1 popular deliquescent substance
lithium bromide
define efflorescent powders
CRYSTALLINE substances that contain water of hydration or crystallization.
this water may be released when substance is triturated or manipulated, and this may cause the powdered substance to become damp or form a paste
why do efflorescent powders pose an issue
because when the water of crystallization or hydration is liberated, the powdered substance may become damp or take the appearance of paste.
as a result of this, a given weight of the prepared powder will not contain the same quantity of drug due to the water loss
name 2 strategies for handling efflorescent powders
-should be stored and dispensed in tight containers (prevents water from being released into the air)
-substitute the anhydrous form of the drug (if the original powder contains water of hydration)
are efflorescent powders more likely to liberate their water in a low or high humidity environment?
low humidity
name a trick to determine if a powder is efflorescent
most have “hydrate” at the end
name 2 popular efflorescent powders
epsom salt (magnesium sulfate heptahyrate)
terpin hydrate
what is the chemical name for epsom salt?
what is epsom salt?
an efflorescent powder
magnesium sulfate heptahydrate
true or false
crystalline substances are stable and have high energy
false - stable and low energy
true or false
when efflorescent powders liberate their water, the physical and chemical properties are changed
true
name 5 different powder dosage forms
topical powders
bulk powders
insufflated powders
divided powders
aerosol powders
what are insufflated powders?
finely divided powders that are intended to be applied to a body orifice
(ears/nose/vagina/tooth socket/throat)
give an example of a kind of product that is an aerosol powder
DPIs (dry powder inhalers)
in powders as DOSAGE FORMS, explain how the composition of the powder should be considered
the size and surface area of the particles should be considered .
these can be controlled to control the therapeutic effect
explain the requirements for topical powder dosage form
the powder should be uniform and a small enough particle size that does not irritate the skin
must pass through at least No. 100 mesh sieve (150 MICRONS)
Explain the components of the topical powder dosage form
a base
adherent
possibly an active ingredient
aromatic material
as mentioned, the topical powder dosage form contains:
-a base
-an adherent
-possibly an active ingredient
-an aromatic material
give examples of a base and adherent that can be used in a topical powder dosage form
base – cornstarch or talc
adherent – magnesium stearate, calcium stearate, zinc stearate
give 8 examples of bulk powders in the market
antacids
laxative powders
douche powders
dentrifices
denture powders
brewer’s yeast powder (B complex vitamin)
medicated powders
nonmedicated powders
commercial name for vitamin B complex bulk powder
Brewer’s yeast powder
what kind of drugs can NOT be used in bulk powders and why
potent drugs.
if you use a potent drug, any slight variation in dosage will affect the therapeutic effect a lot
ex - Brewer’s yeast powder (vit b complex) bulk powder is sprinkled onto food
what are divided powders?
SINGLE DOSE PACKAGE of powder with paper
give 3 examples of products that are divided powder dosage form
headache powders
powdered laxatives
douche powders
_____ powders offer a convenient way to dispense nonpotent drugs
bulk powders
explain the container(s) in which bulk powders are dispensed
in wide mouth powder squares or other wide mouth containers
shaker-top cap can be used
how is the dose of bulk powders measured?
by the pt or caregiver at time of administration using a household measuring device like spoon or cup
what is an advantage of divided powder dosage form over bulk powder
for bulk powder, potent drugs can’t be used and delivery of API in each dose is not consistent
divided powder dosage form provides more dose control
are bulk powders used locally or systemically?
could be either
for local, can use the shaker-top cap to sprinkle onto the skin
for systemic, you have to roughly measure thee amount to take
name 3 kinds of storage/dispensing devices for topical liquids
yorker sprout cap
disc-top cap
flip-top cap
true or false
bulk powders are only used for systemic effects
false – could be systemic or local
true or false
bulk powders are a convenient method to dispense nonpotent drugs
true
how many kinds of powder papers are there?
name them
4:
vegetable parchment
white bond
glassine
waxed paper
explain what vegetable parchment is
a powder paper that is thin, semi-opaque, and moisture resistant
explain what White Bond is
a powder paper that is opaque with NO moisture resistant properties
explain what Glassine is
a glazed, TRANSPARENT, moisture-resistant powder paper
explain what waxed paper is
a transparent and waterproof powder paper
in which powder paper should a hygroscopic and photosensitive material be stored?
should be double wrapped in white bond and in waxed paper
white bond is opaque
waxed paper is WATERPROOF
waxed paper should directly encounter the powder (not the white bond) bc it is water proof. Hygroscopic substance will not absorb any water from the atmosphere
true or false
white bond is waterproof
FALSE – has no moisture resustant properties
cannot be used for a hygroscopic substance – waxed paper should be used bc it is true waterproof
true or false
waxed paper is a transparent powder paper
true
define granules
agglomerates of smaller particles
how are granules prepared
by moistening the desired powder or blended powder mixture (API + excipients) and passing this moistened mass through a screen of the mesh size that will produce the desired granules, then dries
true or false
powders are generally more stable than their corresponding granules
FALSE
granules are generally more physically and chemically stable than the corresponding powders
which are MORE LIKELY to cake and harden — granules or powders
powders
which are preferred for the making of solutions – granules or powders?
granules
give 2 examples of products that use granules in solution
antibiotic granules – (ampicillin) Principen
laxative granules – senokot
granules normally have what kind of surface?
what does this mean?
a rough surface – uptakes water quickly and granules quickly dissolve
which has more of an issue with morphology and flow - powders or granules
powders
give an example of a granulated product
effervescent granulated salts
what is an advantage of effervescent granulated salts
the carbonation can mask the bitter/unpleasant taste of the drug
how are effervescent granulated salts taken?
they’re ingested orally
explain how effervescent granulated salts have the bubbly effect
1 method: 1 MOL citric acid reacts with 3 MOL sodium bicarbonate to produce sodium citrate + 3 MOLCARBONATE + 4 MOL H2O
2nd method: 1 MOL tartaric acid reacts with 2 MOLsodium bicarbonate to produce sodium tartrate + 2 MOL carbonate + 2 MOLwater
it’s common to use a combination of both methods
besides masking the taste, how else is the carbonation an advantage in efferevescent granulated salts
bubbles will break down the granules and increase the dissolution – helps the API to dissolve and form a solution
