Pharmaceutical Powders

Question 1

Type of pharmaceutical powders:

Answer 1

-Dusting powder
-Oral powder in sachets
- Powders for reconstitution
- inhalation or insufflation products
- bulk powders for tablets and capsules manufacture

Question 2

Crystalline

Answer 2

Sucrose molecules align and form large “lattices” of molecules, regular repeating structure

Molecules packed in a defined (long range) order
Cool slowly to below melting point
Melt ↔ freeze
Polymorphs, solvates or hydrates, co-crystals

Question 3

amorphous

Answer 3

molecules of a different size and shape (glucose and fructose) get in the way of the sucrose molecules and stop crystals forming

Molecules packed in a random (short range) order
Rapid solidification/precipitation
Glassy ↔ rubbery (transition)
Moisture sensitive, dissolves faster

Question 4

Polymorphism

Answer 4

Different molecular packing arrangements (of the same chemical substance) in the crystal lattice

Question 5

How to determine if a drug is crystalline or amorphous?

Answer 5

X-ray diffraction

Question 6

X-ray reading - cyrstalline

Answer 6

Very defined shape, high intensity and narrow peaks

Question 7

X-ray reading - amorphous

Answer 7

low intensity and broad peaks

Question 8

What is the stages to amorphous > crystalline?

Answer 8

Amorphous > metastable polymorph > stable polymorph > highly crystalline

Question 9

hydrate

Answer 9

If water is present in the crystal lattice

Due to small molecular size of water and multidirectional hydrogen bonding capability of water
Anhydrous = no water

Question 10

solvate

Answer 10

If solvents are present in the crystal lattice

Ethanol > ethanolate
DMSO (dimethyl sulfoxide)> DMSO solvate

Question 11

Give a drug example of a hydrate?

Answer 11

Lisinopril
10mg, 89mg of lisinopril dihydrate

Question 12

Salt formation ________ the solubility and dissolution rates of acidic and basic drugs

Answer 12

increases

Question 13

Salt form structure

Answer 13

lattice of positive ions with deprotonated acid negative ions

Question 14

Give a drug example of a salt form:

Answer 14

Amlodipine - besilate

10mg of amlodipine

Question 15

What are Co-crystals?

Answer 15

Two or more molecules within the same crystal lattice
In a definite stoichiometric ratio
Not based on ionic bonds

Question 16

Give two examples of co-crystals?

Answer 16

1) Sildenafil
2) Aspirin - has antiplatelet activity to combat heart attacks and strokes

Question 17

What are primary features of powder?

Answer 17

• particle size = uniformity, flow, mixing
• surface area = dissolution rate
• shape = uniformity, flow, mixing

Question 18

secondary features of powder?

Answer 18

• Density = size of tablets and capsules
• Porosity = compressibility, permeability/ water uptake of tablets
• flowability = content uniformity
• compressibility = essential to manufacture of tablets

Question 19

Equivalent diameters

Answer 19

d”

Question 20

dp

Answer 20

Projected perimeter diameter

Question 21

da

Answer 21

Projected area diameter

Question 22

df

Answer 22

Feret’s diameter

Question 23

dM

Answer 23

Martin’s diameter

Question 24

ds

Answer 24

Sieve diameter

Question 25

dv

Answer 25

Diameter of equivalent volume sphere

Question 26

dsa

Answer 26

Diameter of equivalent surface area sphere

Question 27

dmass

Answer 27

Diameter of equivalent mass sphere

Question 28

dst

Answer 28

Stokes’ diameter
Diameter of a sphere with the same density and settling velocity as the particle

Question 29

dae

Answer 29

Aerodynamic diameter
Diameter of a sphere with the same terminal velocity in air or some other relevant fluid as the particle

Question 30

dhyd

Answer 30

Hydrodynamic diameter
Diameter of a sphere that diffuses at the same rate in a liquid as the particle

Question 31

What equivalent diameters would be used for paint pigment particles?

Answer 31

Projected area diameter

Question 32

Which equivalent diameter should I choose for aerosol deposition in the lungs?

Answer 32

Aerodynamic diameter

Question 33

Which equivalent diameter should I choose for sedimentation properties of the material?

Answer 33

Stokes’ diameter

Question 34

Particle shape - specify:

Answer 34

Solid irregular particles

Porous irregular particles

Question 35

List the Particle shape terminology

Answer 35

Acicular
Rod-shaped

Flacky
Dendritic

Porous
Angular/irregular
Spherical
Rounded

Question 36

Good flowability means

Answer 36

easy mixing = rounded or spherical

Question 37

if the particle shape is acicular/ rod-shaped what does this mean for mechanical strength

Answer 37

increased - tendency to interlock

angular/irregular

Question 38

What type of particle size if Cohesive effects due to greater surface area

Answer 38

flaky

Question 39

How to calculate: Surface area (unit2)?

Answer 39

Surface area = 2(length × width) + 2(width × height) + 2(length × height)

Question 40

Specific surface area per weight unit (Sw)

Answer 40

Weight-specific surface area= [surface area/weight]

Question 41

Sv = Volume-specific surface area

Answer 41

[surface area/volume]

Question 42

A ___ particle may be best described as matter of a small size with an immensely ____ surface-to-volume ratio

Answer 42

small
high

Question 43

Noyes-Whitney Equation

Answer 43

A greater surface area leads to an increase in dissolution rate and improved bioavailability

dC/dt = DA (Cs-C) / h

Question 44

Surface area measurement , what theory?

Answer 44

Brunauer–Emmett–Teller (BET) theory
Stephen Brunauer, Paul Hugh Emmett, and Edward Teller