Lecutre 1 Powders and Granules

Question 1

What is a powder?

Answer 1

A dry substance composed of finely divided particles which may be used for internal or external use.

Question 2

What can particle size effect?

Answer 2

Dissolution rate (Stoke’s Law), suspendability of suspensions (accurate dosing), uniformity of mixtures in liquids, penetrability of particles for inhalation (narrow window 1-10 microns), lack of grittiness for dermatologicals.

Question 3

Why does particle size matter?

Answer 3

1. Uniform particle size aids in mixing and distribution.2. Migration may occur with differences in particle size.3. Differences may change the color intensity of a powder.4. Especially important in dermatologicals.

Question 4

What is the study of small particles?

Answer 4

Micromeritics.

Question 5

Micromeritics includes the study of …

Answer 5

particle size and particle size distribution, uniformity, morphololgy, flow, porosity, volume, density, ,compatibility with other formulation components.

Question 6

What is the purpose of particle size analysis?

Answer 6

To obtain quantitative data on the size, distribution an morphology of powders.

Question 7

What size range can powders be?

Answer 7

Extremely coarse (10 mm) to extremely fine (1 micron or less)

Question 8

What are the USP descriptive terms?

Answer 8

very coarse, coarse, moderately coarse, fine, and very fine

Question 9

Particle Size and Analysis

Answer 9

Very Coarse #8 Sieve 2,360 micrometerCoarse #20 Sieve 850 micrometerMod. Coarse #60 Sieve 425 micrometerFine # 60 Sieve 250 micrometerVery Fine #80 Sieve 180 micrometer

Question 10

What are the five different methods of particle size analysis?

Answer 10

Sieve Analysis, Microscopy, Sedimentation Rate, Laser Light Scattering or Diffraction, Cascade Impaction.

Question 11

How is Sieve Analysis preformed?

Answer 11

Particles are passed by mechanical shaking through a series of sieves of known and successively smaller size.

Question 12

How does Microscopy determine particle size?

Answer 12

Particle size is determined by visual observation with the use of calibrated grid background or other measuring device.

Question 13

What does a cascade impactor measure particle size for?

Answer 13

For inhalation dosage forms

Question 14

What is powder flow impacted by?

Answer 14

size, shape, porosity

Question 15

What is powder flow characterized by(tests)?

Answer 15

angle of repose, and carr index(compressibility Index)

Question 16

What does Angle of Repose estimate and how is it measured?

Answer 16

Estimates flow properties and is a measure of the angle formed when powder is allowed to flow freely from a known height. Tan 0 = h/r

Question 17

If a powder has a low angle of repose what does this mean?

Answer 17

The powder flows freely

Question 18

What does tapped and bulk density determine?

Answer 18

Powder flow and compressibility

Question 19

What is tapped and bulk density useful for?

Answer 19

It helps determine storage needs.

Question 20

What is the CARR INDEX equation?

Answer 20

% compressibility = (Tapped Density - Bulk Density) / Tapped Density x 100As Zakiya says throw back Thursday

Question 21

A compressibility range of 5-15 means the flow is?

Answer 21

Excellent (free flowing)

Question 22

A compressibility range of 12-15 means the flow is?

Answer 22

Good (free flowing powdered granules)

Question 23

A compressibility range of 18-21 means the flow is?

Answer 23

Fair (powdered granules)

Question 24

A compressibility range of 23-28 means the flow is?

Answer 24

Poor (very fluid powders)

Question 25

A compressibility range of 28-35 means the flow is?

Answer 25

Poor (fluid cohesive powders)

Question 26

A compressibility range of 35-38 means the flow is?

Answer 26

Very poor (fluid cohesive powders)

Question 27

A compressibility range greater than 40 means the flow is?

Answer 27

Extremely poor (cohesive powders)

Question 28

What is the process of reducing the particle size of a solid substance to a finer state of subdivision?

Answer 28

comminution

Question 29

What are the reasons to reduce particle size?

Answer 29

1. Facilitate crude drug extraction2. Increase the dissolution rates of drugs3. Aid in the formulation process4. Enhance absorption

Question 30

What are extemporaneous processes that can have the affect of communition?

Answer 30

TriturationPulverizationLevigation

Question 31

What is continued rubbing of a solid in a mortar with a pestle to reduce the particle size?

Answer 31

Trituration

Question 32

What is communition by utilizing a solvent that can be easily removed?

Answer 32

Pulverization

Question 33

What is communition by triturating while moistened with a liquid in which the powder is insoluble?

Answer 33

Levigation

Question 34

What are the different ways to reduce particle size industrially?

Answer 34

Milliing (Ball Mills, Roller Mills, Cutter Mills, Hammer Mills, Colloid Mills, Fluid Energy Mills), Lyophilization, Spray Drying

Question 35

What are the 5 different ways to blend powders?

Answer 35

Spatulation, Trituration, Tumbling, Specialized equipment, and Geometric Dilution.

Question 36

What is spatulation?

Answer 36

Mixing of powders on an ointment slab or pad using a spatula; no particle size reduction.

Question 37

What is trituration?

Answer 37

Continued rubbing of a solid in a mortar with a pestle to reduce the particle size.

Question 38

What is tumbling?

Answer 38

Uses clear glass or plastic bottles and zipper sealed plastic bags to mix powders.

Question 39

What type of blending is used when blending two or more powders of unequal quantities to ensure that small quantities of usually potent drugs are uniformly distributed throughout the powder mixture?

Answer 39

Geometric Dilution

Question 40

What do you use to blend powders industrially?

Answer 40

Tumblers(double cone blender and twin shell blender) and paddle blenders

Question 41

What are the 4 factors that have to be considered when blending?

Answer 41

size, shape, density, electrostatic forces

Question 42

What is a powder used to clean teeth?

Answer 42

Dentrifrices

Question 43

What is a powder intended for application to body cavities?

Answer 43

Insufflations

Question 44

What are substances that absorb moisture from the air?

Answer 44

Hygroscopic

Question 45

What are substances that absorb moisture from the air to the extent that they liquefy by partially or wholly forming a solution?

Answer 45

Deliquescent

Question 46

What are crystalline substances that become powdery and liberate their water of hydration when they are manipulated or stored under conditions of low relative humidity?

Answer 46

Efflorescent Powders

Question 47

What is a mixture of certain components with a melting point less than room temperature; thus, they liquefy when in close and prolonged contact?

Answer 47

Eutectic Mixtures

Question 48

How can you avoid eutectics?

Answer 48

Dispense powders separately, add an absorbent powder, keep ingredients separated as much as possible, make the eutectic, then add absorbent to incorporate the liquid.

Question 49

What are some absorbent powders that can be used to avoid eutectics?

Answer 49

talc, starch, lactose, calcium phosphate

Question 50

What are granules?

Answer 50

Prepared agglomerates of powdered materials ranging from 4 to 10 mesh in size.

Question 51

How do you prepare a granule?

Answer 51

Prepared by moistening blended powders and by passing this mass through a screen or a granulator. Granules are then air or oven dried. Flavors can be sprayed on the granules and then dried.

Question 52

What is an effervescent granule?

Answer 52

Contains mixtures of citric acid, tartaric acid, or sodium biphosphate with a bicarbonate and a medicinal agent. The carbonated solution is a pleasant vehicle and lessens the bitter and salty taste of salts.