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Flashcards in Lecture 10 Deck (29)
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1
Q

Powders

A

Mixture of drug, finely divided drugs, and/or chemicals that may be intended for internal or extended use

2
Q

Granules

A

Agglomerates of powders materials, that may be used per se for the medicinal value of the content, or used for making other pharmaceutical dosage forms for tablets or capsules.

3
Q

Micromeritics

A

Science and technology of small particles

4
Q

Derived Properties of Powders/Granules (5)

A
  1. Porosity of powder
  2. Packing arrangement
  3. Density
  4. Flow (angle of repose)
  5. Dissolution rate
5
Q

Fundamental Properties of Powders/Granules (4)

A
  1. Particle size
  2. Size distribution
  3. Shape (morphology)
  4. Surface Area
6
Q

Influencers of Size Influences (5)

A
  1. Dissolution rate of particles (decreased size and increased rate)
  2. Suspendability of particles (suspension)
  3. Uniform distribution of a drug in a powder mixture (dose-to-dose uniformity)
  4. Inhaled drug delivery
  5. Lack of grittiness of particles in dermal ointments, creams, and ophthalmic preparations
7
Q

Size + Solubility

A

Smaller the size, greater the surface area, the higher the solubility.

8
Q

Determinants of Particle Size (5)

A
  1. Sieving
  2. Microscopy
  3. Sedimentation
  4. Light diffraction/scattering
  5. Cascade impaction
9
Q

Sieving Method

A
  • particle size analysis
  • from a cm down to a few nm
  • Passing powders through standard sieves while being shaken
  • Ranges from very coarse, moderately coarse, coarse, fine, and very fine
  • Higher the sieve number the finer the powder
10
Q

Mesh Size Meaning

A

Number of sieves per inch. Smaller the opening as the mesh size number increases

11
Q

Particle Size Distribution Importance

A

Formulations have same average particle size but different size distributions

12
Q

Powder Shape

A
  • Aka Morphology
  • Shape affects surface area of particle and behavior when surrounded by other particles
  • Behaviors affected are flow and packing
13
Q

Shape Characterizations (5)

A
  1. Spherical
  2. Rounded
  3. Acicular (needle-like)
  4. Flake
  5. Irregular
    * *Determined via microscopic techniques**
14
Q

Components Affecting Surface Area (2)

A
  1. Size reduction (micronized)

2. Shape - can increase or decrease SA depending on shape

15
Q

Porosity

A

Measures of void spaces in bulk powder

  • Low porosity - little void volumes in powder
  • High porosity - large void volumes in powder (more reaction potential)
16
Q

Porosity Affect (3)

A
  1. Disintegration/dissolution
  2. Drug diffusion
  3. Absorption
17
Q

Two Ways Drugs can Enter System

A
  1. Diffuse from the matrix

2. Matrix dissolves to release the drugs (dissolution)

18
Q

Ideal Packing Assumptions

A

Uniformed Size, sperical powder beds

19
Q

Ideal Packing Arrangements (2)

A
  1. Closest or rhombohedral - ~26% porosity

2. Open or cubic - ~48% porosity

20
Q

Non-Ideal Packing Scenarios (3)

A
  1. Neither spherical nor uniform size - intermediate packing
  2. Large particle size distribution - smaller particle shift between layers, lower porosity
  3. Form aggregates - bridging, arching, clinging, and ratholing in packing. Higher porosity
21
Q

Density

A

Ratio of mass of sample to volume

22
Q

Density Depends on (2)

A
  1. Type and arrangement of atoms in molecule

2. Arrangement of molecules in sample (crystalline)

23
Q

Density Influences (3)

A
  1. Flow
  2. Powder blending
  3. Tableting/capsuling
24
Q

Types of Density (2)

A
  1. Bulk Density

2. Tap Density

25
Q

Flow Properties and Affects

A

Either free flowing or stick

Affects:

  1. Blending - homogeneity of mixture
  2. Tablet/capsuling - content and weight uniformity
26
Q

Factors Influencing Powder Flow (6)

A
  1. Particle morphology
  2. Crystallinity
  3. Particle density
  4. Surface area
  5. Particle size and size distribution
  6. Moisture in powder
27
Q

Angle of Repose

A
  • Pouring of powder into a pile
  • Angle created from the edge of pile to the surface is the angle of repose
  • The smaller the angle of repose the better the powder flow
28
Q

Comminution

A

Micronization of Drugs

29
Q

Comminution Types (3)

A
  1. Small scale - mortar & pestle to titrate or comminution
  2. Large scale - mills and pulverizers
  3. Levigation - small scale prep of ointment or suspension. Grind down powders and add in small amount of liquid or base to further grind it down before adding in remaining base. Reduces grittiness of powders.