Pharmaceutics Ii (Ti): Powders And Granules

Front 1

What is a powder?

Back 1

a mixture of dry, finely divided drug and/or chemicals that is intended for internal or external use

Front 2

What is a granule?

Back 2

dry aggregates of powder particles

Front 3

9 adv.s of powder?

Back 3

1. flexibility of compounding

2. good chemical stability

3. rapid dispersion of ingredients

4. little or no disintegration reqd

5. rapid onset of action

6. easy to administer to elderly and children

7. can be mixed with food or liquids

8. a better choice if drug is too bulky to be prepped as tab or cap (ex. metamucil)

9. prep. as individualized doses

Front 4

4 Disadv.s of powder?

Back 4

1. time consuming preparation

2. inaccuracy of dose because of bulk

3. unpleasant tasting, hygroscopic and deliquescent (absorbs moisture, melts away)

4. pt. has to measure the amt taken

Front 5

Powder classifications are based on what?

Back 5

size

Front 6

When are powders sometimes modified?

Back 6

before use as a pharmaceutical component

Front 7

Range of particle sizes?

Back 7

from very coarse to extremely fine approaching colloidal dimension (1 micron or less)

Front 8

The descriptive terms utilized by the USP to characterize particle size?

Back 8

Very coarse, coarse, moderately coarse, fine, and very fine related to the proportion of powder that passes thru opening of standard sieve in a specific time while being shaken

Front 9

Particle size is described in terms of what?

Back 9

sieve number or mesh fraction (a large sieve number = a smaller sieve opening)

Front 10

Sieve No. 8 corresponds to what particle size?

Back 10

very coarse

Front 11

Sieve No. 80 corresponds to what particle size?

Back 11

very fine

Front 12

Sieve No. 20 corresponds to what particle size?

Back 12

coarse

Front 13

Sieve No. 60 corresponds to what particle size?

Back 13

fine

Front 14

Sieve No. 40 corresponds to what particle size?

Back 14

moderate

Front 15

Particle size of a powder can influence what 5 things?

Back 15

1. suspendibility

2. uniform distribution

3. penetrability

4. dissolution rate and bioavailability

5. lack of grittiness

Front 16

Explain how particles size influences suspendability?

Back 16

(suspension and solution) need uniform dispersion in liquid vehicle (1-50 microns)

Front 17

Explain how particle size influences uniform distribution?

Back 17

ensures dose to dose content uniformity

Front 18

Describe how particle size influences penetrability of particles?

Back 18

refers to the penetrability of particles for inhalation (about 5-20 microns)

Front 19

Describe how part. size influences dissolution rate and bioavailability?

Back 19

dissolution rate and bioavailability often depend on particle size of drug

1. reduction in particle size (micronization) can increase dissolution rate and enhance bioavailability

2. the smaller the particle size of the drug, the larger the surface area and the faster the rate of dissolution

(ie, larger SA = Greater dissolution = Greater bioavailability)

Front 20

3 methods of determining particle size?

Back 20

1. sieving

2. microscopy

3. sedimentation

Front 21

Describe the process of sieving?

Back 21

it is one of the simplest and more frequently used methods of determining particle size distribution

-involves size classification followed by the determination of the wt. of each fraction

-part.s are passed by mechanical shaking thru a series of sieves of known and successively smaller size and determination of the proportion of powder passing thru or being withheld on each sieve (range 40-9500 microns)

Front 22

Particle size range for sieving?

Back 22

40-9500 microns

Front 23

US standard sieves available?

Back 23

3&1/2 to 400 mesh (larger mesh = smaller particle size)

Front 24

Descrbie the process of microscopy?

Back 24

one of the most accurate and direct methods of particle size determination...particles are sized thru the use of a calibrated grid background incorporated into the microscope (range 0.2 to 100 micrometers)

Front 25

Describe the process of sedimentation?

Back 25

it is a method of part. size determination using ANDREASEN PIPET, a special cylindrical container from which sample can be removed from the lower portion at selected intervals....the powder is dispersed in a nonsolvent in the pipet, agitated and 20 mL samples are removed, dried and then weighed. (powder settles in solvent)

Front 26

Comminution or milling refers to what?

Back 26

particle size reduction

Front 27

Particle size reduction on a lg scale involves the use of what?

Back 27

mills

Front 28

Particle size reduction on a small scale involves what?

Back 28

using a mortar to triturate

Front 29

List 3 methods for particle size reduction?

Back 29

1. trituration

2. pulverization by intervention

3. levigation

Front 30

What is trituration?

Back 30

a method of particle size reduction that involves the use of a mortar and pestle to grind solid to reduce its particle size and/or mix two or more substances intimately

Front 31

What is pulverization by intervention?

Back 31

a method of part. size reduction...material is dissolved in a small amt of volatile solvent (alc. or ether) solution may be spread on tiles of mortar or tile. Solvent is evaporated, film of fine crystals scraped off...done to increase SA by decreasing part. size

Front 32

Give two examples of pulverization by intervention?

Back 32

1. iodine crystals and ether

2. camphor crystals and alcohol

Front 33

What is levigation?

Back 33

a method of part. size reduction...a paste is formed by the addn of a levigating agent to the solid material. The rubbing the paste in a mortar and pestle or by use of an ointment slab (the paste is triturated to decrease particle size) (the paste is then added to an oint. base and mixed in a "figure 8", to make uniform and smooth on pile tile with spatula

Front 34

Give ex.s of levigating agents? (3)

Back 34

1. glycerin

2. M.O.

3. propylene glycol

Front 35

3 types of mortars?

Back 35

1. wedgwood

2. porcelain

3. glass

Front 36

Which types of mortars have a rougher surface? What does this result in?

Back 36

wedgwood and porcelain...fine grinding action results in finer/smaller particles

Front 37

Which of the different mortar types has a smooth surface? What does this result in?

Back 37

glass...less grinding

Front 38

5 types of powder blending?

Back 38

1. spatulation

2. trituration

3. geometric dilution

4. sifting

5. tumbling

Front 39

Describe spatulation?

Back 39

a method of powder blending

1. blending sm. amts of powders by mvmt of spatula on a sheet of paper or ointment tile

2. very little compression or compacting of the powder occurs

3. not suitable for large qtys of powders

4. not suitable for powders containing potent (ex. nitroglycerin, digoxin) drug because homogenous blending is not certain

5. exp. suited for eutectic mixturs

Front 40

What occurs if you keep a eutectic mixture mixed?

Back 40

they liquify

Front 41

Define eutectic?

Back 41

solid subst.s that liquify

Front 42

Give 6 examples of eutectic substances?

Back 42

1. phenol

2. menthol

3. camphor

4. thymol

5. aspirin

6. phenylsalicylate

Front 43

How do you solve the problem of a eutectic mixture?

Back 43

first mix the eutectic solid with an inert diluent (MgO, Mg Carbonate, etc) that physically separates eutectic forming ingredients

Front 44

What is trituration?

Back 44

a method of powder blending...inv.s the use of a glass mortar for simple mixing...reduces particle size and blends (not very fine grinding)

Front 45

What is geometric dilution?

Back 45

when a small amt of potent substance is to be mixed with a large amt of diluent by trituration (either oint. or powder)(figure 8s)

Front 46

What is sifting?

Back 46

a method of powder blending where powders are mixed by passing powders thru sifters...this is not good for mixing potent drug incorporation

Front 47

Describe tumbling?

Back 47

a method of powder blending...inv.s mixing powders in a rotating chamber with the use of a motorized blender, mixing is accomplished by tumbling motion...sometimes use blending blades to help mixing...mixing is thorough but time consuming