PHRD5925 Pharmaceutics Lecture 16 - Pharmaceutical Powders

  1. do most pharmaceutical powders show a normal size distribution?
    NO
  2. PDI
    polydispersity index (squared std dev./mean diameter)
  3. PDI < 0.1
    monodisperse particles
  4. 5 pharmaceutical bulk properties affected by particle size
    • 1) bulk density
    • 2) porosity
    • 3) surface area
    • 4) flowability
    • 5) dissolution/wettability/solubility
  5. density without consideration of voids (no inter/intra-particle pores)
    true density
  6. density that includes inter/intra-particle spaces of the particle when considering the volume
    bulk (apparent) density
  7. measure of void volume in a powder material
    porosity
  8. defines how cohesive/adhesive something is
    contact angle (Image Upload 2)
  9. larger contact angle = _____ wettability
    lower
  10. help solvent penetrate the pores of the powder
    wetting agents
  11. smaller particle size = ____ angle of repose (Image Upload 4)
    larger (decreased flow)
  12. process of reducing particle size or aggregates of powders
    milling (comminution)
  13. 3 methods of milling/comminution
    • 1) trituration
    • 2) pulverization by intervention
    • 3) levigation
  14. continuous rubbing/grinding w/ a mortar & pestle; useful for hard powders
    trituration
  15. useful for hard, crystalline powders that do not easily triturate or gummy substances
    pulverization by intervention
  16. uses a small amount of solvent in which the particles are insoluble, then triturate w/ mortar & pestle; useful when making ointments & suspensions
    levigation
  17. blending needs to be redone if RSD > _____
    6%
Author
daynuhmay
ID
271311
Card Set
PHRD5925 Pharmaceutics Lecture 16 - Pharmaceutical Powders
Description
Pharmaceutical Powders
Updated