PHRD5925 Pharmaceutics Lecture 20 - Interfacial Phenomena & Rheology

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  1. boundary between 2 distinct phases in a system
  2. phenomenon in which a liquid or solid is in contact w/ a gas
    surface tension
  3. compounds that concentrate at the solution surface & decrease surface tension
    surface-active agents
  4. why would you want to decrease surface tension?
    to allow water molecules to interact with drugs in 3 dimensions
  5. what adsorption of solutes by solid particles is limited by
    formation of a monolayer on the solid particles
  6. association formula
    kon x conc x unbound sites
  7. dissociation formula
    koff x bound sites

    (dissociation is NOT related to concentration)
  8. chromatography based on hydrophilic interactions/displacement by nonpolar organic solvents
    normal phase
  9. chromatography based on hydrophobic interactions/displacement by polar aqueous solvents
    reverse phase 
  10. 3 oral solids that bind drugs
    • activated charcoal
    • antacids
    • sucralfate
  11. adsorption of pure liquid to solid particles and formation of liquid film over the particle surface
  12. positive adsorption
    solute adsorbed
  13. negative adsorption
    solvent adsorbed
  14. most common surfactants in pharmaceutics
    non-ionic surfactants
  15. HLB - hydrophilic-lipophilic balance
    allows comparison between surfactants w/ different polar & non-polar groups
  16. HLB range of O/W emulsions
  17. HLB range of W/O emulsions
  18. science of flow and deformation of matter
  19. how quickly the velocity of something changes when force is applied
  20. a material's viscosity-dependent flow properties as a liquid and its elastic properties as a solid
  21. 2 things sedimentation is dependent on
    • 1) particle size
    • 2) viscosity
  22. why narrow particle size distribution is preferred in pharmacy
    increased stability
  23. formula that describes rate of transport across skin
    Fick's Law
  24. contains one or more chemical substances dissolved in a suitable solvent or mixture of miscible solvents
    liquid formulation
  25. liquid preparation containing very fine powders of solid materials or dilute dispersed liquid substances
  26. semisolid preparation intended for external application to the skin or mucous membranes
  27. semisolid dosage form containing one or more drug substances dissolved or dispersed in a suitable base
  28. 2 types of creams
    • O/W emulsion
    • W/O emulsion
  29. W/O emulsifier added to hydrocarbon base to improve water absorption
    absorption base
  30. semisolids consisting of suspensions made up of either small inorganic particles or large organic molecules interpenetrated by liquid
  31. prepared to contain large amount of solids dispersed in a base; stiffer than ointments, remain on skin
  32. grinding a dry solid material
  33. mixing a solid material and a wet non-solvent
  34. grinding of a dry solid material with a wet solvent
    pulverization by intervention
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PHRD5925 Pharmaceutics Lecture 20 - Interfacial Phenomena & Rheology
Interfacial Phenomena & Rheology
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