Materials and Excipients I

Question 1

What is the purpose of using different materials?

Answer 1

Properties of formulations can effect drug performance, quality, appearance, dosage, effect on patient

Question 2

What can form from a solid?

Spider diagram

Answer 2

Solid > Amorphous or crystal

Crystal > Polymorphs, Solvates/hydrates or co-crystals

Question 3

What is the difference between crystalline and amorphous?

Answer 3

Crystalline - Molecules packed in long-range order, have a mp
Amorphous - No long-range order (irregular pattern), glass transition temperature (Tg), high dissolution rate, unstable

Question 4

Define glass transition temperature

Answer 4

Temp where 30-50 C-chains move, amorphous changes from rigid to flexible state (solid to rubbery)

Question 5

Define polymorphs

Answer 5

Same molecule exists as two/more crystalline forms

Question 6

What affects the solubility of crystals?

Answer 6

Anhydrates and solvates

Question 7

What are co-crystals?

Answer 7

A crystal between two different molecules

Question 8

Describe hydrates

Answer 8

Have lower H2O solubility than anhydrates with bonds btw H2O and drug

Question 9

Why do hydrates have a lower H2O solubility?

Answer 9

H2O in crystal already solvating the drug so lower solubility as its already solvated

Question 10

How does the drug go into solution?

Answer 10

If the bonds release enough energy to overcome IMF, drug goes into solution

Question 11

Which properties differ between different crystals?

Answer 11

Mp, solubility, dissociation rates, bioavailability, stability, material prop, processibility

Question 12

Name and describe a method of processing materials

Answer 12

Milling (Grinding):

1) Powder flows into die (mold) > Particle size affects flow
2) Compress powder granules together into tablet

Question 13

What are the properties of solids?

Answer 13

Brittleness, toughness, surface hardness, elasticity, plasticity, ductility

Question 14

What is the purpose of milling solids?

Answer 14

Reduces particle size which means drug dissolves better, flows better

Question 15

Describe the difference between brittleness and toughness

Answer 15

Brittle - Easily broken on impact

Toughness - Ability to withstand impact

Question 16

Define hardness

Answer 16

Ability to withstand scratching

Question 17

Describe hardness

Answer 17

Measured by Mohs’ scale - Diamond is hardest, scratches everything below it

Question 18

How does temperature affect hardness?

Answer 18

Decreasing temp increases hardness

If tablet easily scratches, coating could be removed

Question 19

Define elasticity

Answer 19

Ability to return to its original shape after stretched

Question 20

Describe elasticity

Answer 20

Has an elastic limit (snaps), difficult to mill as it returns to original shape, breaks flat when milled (brittle fracture)

Question 21

Define plasticity

Answer 21

Ability to hold shape after stretched without breaking

Question 22

Describe plasticity

Answer 22

Heating increases plasticity

When milled, absorbs energy used to crush it - wastes energy

Question 23

Define ductility

Answer 23

Ability to be stretched by a force into thin wire

Question 24

Describe ductility

Answer 24

Bad for milling as energy is wasted

Question 25

What are the 3 methods of measuring material properties?

Answer 25

Compression, Tension and Rotation

Question 26

Describe compression

Answer 26

Measures brittle/hardness of tablet - How much energy it takes/absorbs

Question 27

Describe tension

Answer 27

Measures elasticity/plasticity - The force put in

Question 28

Describe rotation

Answer 28

Measures liquid/gel via a rod - How much force it takes to rotate it