Micromeritics Flashcards
Def of micromeritics:
science and tech of small particles
What types of forms are in the optical microscope range?
- emulsions
- suspensions
- fine powders
What types of forms are in the sieve range?`
- coarse powders
- tablet granules
- granular salts
What is the frequency distribution curve?
# of particles lying within certain size range plotted against the mean - shows the entire size range
What is the polydispersity index (PDI)?
quantitative measure of size distribution
- between 0-1
- the higher the #, the higher the variability in size
What are some ways you can determine particle size?
- microscopic
- sieving
- sedimentary
How do you utilize the microscopic method?
- count 200+ particles in a plane
2. # of particles per group are multiplied by mean of particle size range
How do you utilize sieving method?
- particles get shaken through sieves
2. quantity of powder resting on each sieve is weighted and converted to %
How do you utilize sedimentation method?
particle size is obtained by gravity
Particle surface area is found via…
- adsorption method
- air permeability method
How do you utilize the adsorption method?
amount of gas/liquid adsorbed onto sample of powder
- direct function of SA
How do you utilize the air permeability method?
rate at which gas/liquid permeates through powder
- related to SA exposed
What is the bulk volume?
volume taken up by powder in graduated cylinder
For nonporous drugs, the bulk volume is…
equal to true volume
What is the void volume?
volume of space between particles
