Powders (Exam 3) Flashcards
powders
mixture of dry, finely divided drugs/chemicals
external or internal use
drugs have a __________ onset of action due to ___________
rapid
disintegration not being required
powders can _____________ upon standing
cake or harden
label for external powders
external use only
powders are primary ingredients for most other delivery systems such as
solid dosage forms
liquid dosage forms
semisolids
per se medicated powders
bulk powders (internal/external)
divided powders (internal)
divided medicated powders
doses of powders divided into individual packets
active ingredient and inert diluent
more precise dosing
oral bulk medicated powders are measured
volumetrically using measuring spoons or cups and mixed with liquid
oral bulk medicated powders are reserved for
non-potent drugs
oral bulk medicated powders are not used for drugs that
require precise and accurate dosing
mix divided medicated powders with __________ before swallowing
liquid vehicle
bulk volume =
true volume(intermolecular space) + porosity
bulk density
volume of given was of powder, space between powder and porosity of particles
tapped density
packed volume of a given mass of particles under a well defined rate and extent of agitation
true density
density of solid particle alone
powder flow is a product of
the strength of cohesive forces of a powder
factors affecting flow properties of powders
shape and size
powders with a low angle of respose flow
freely
powders with a high angle of repose flow
poorly
angle of repose
tan(angle) = height of cone/radius of cone
how to measure spherical particles
particle diameter
how to measure irregular shaped particles
equivalent spherical diameter (area/volume are the same)
sieve analysis
particles passed by mechanical shaking through series of screens of decreasing size
microscopy
direct technique to determine particle size
uses calibrated grid background
light scattering
most popular
analysis of diffracted light as a laser passes through particles
the reduction of particle size is accompanied by
great increase in surface area of solids
how to reduce particle size
trituration
levigation
pulverization by intervention
trituration
grind powder with mortar and pestle
levigation
powder is mixed with viscous liquid
pulverization by intervention
used with hard crystalline or gummy type substances that do not crush or triturate easily
spatulation
use a spatula
blend powders by moving spatula through them on a slab
spatulation is not suitable for
large quantities of powder
mixtures containing potent substances
trituration is more suitable for
mixtures containing small quantities of drugs
geometric dilution
small amount of drug mix with large amount of diluent
sifting
passing powders through sifters
NO POTENT DRUGS
tumbling
powder blenders or mixers
large scale production
internal bulk powders are labeled with
the weight of active ingredient per volume to be administered
bulk powders contain ____________ substances
nonpotent
another name for divided powders
chartulae
when preparing divided powders, prepare enough powder for
one extra dosage unit
when preparing divided powders, if a small amount of powder is used,
add a small amount of diluent
powder paper for volatile components
glassine
waxed paper
powder papers for non-volatile components
simple bond paper
powder papers with limited moisture resistance
vegetable parchment
glassine
waterproof powdered paper
waxed paper
hygroscopic powder
absorb moisture from the air
deliquescent powder
absorb moisture and dissolve to form solution
aerosol powders
particle size 1-6 um
inert propellants and diluents are added to aid in flow properties and uniformity
