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Flashcards in The Solid State Deck (19)
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1

Why are solids important In the pharmaceutical sector? (2)

- many medicines are in solid dosage form

- solid properties affect the importance of medicines by dictating key performance parameters like solubility

2

What happens with Norvir?

It was a drug which failed the dissolution test due to the solid form due to formation of crystals which affected its dissolution.

contains Ritonavir

3

Solid properties (3)

rigid structure

resist changes to shape and volume

physical state of matter

4

Types of solid forms: (2)

Crystalline - order of the arrangement is the same throughout the whole structure

Amorphous - order of the arrangement of molecule differs through the structure.

5

Crystalline solid facts (4)

made up for repeating units

defined geometric shape

sharp melting point

have long and short-range order

6

Amorphous solid facts (4)

no sharp melting point but have a glass transition temperature (transition to semi-solid)

irregular molecule arrangement

thermodynamically less stable than crystals

only have short-range order

7

How does a X-ray diffraction shows us if a solid is crystalline or amorphous?

crystalline - distinct sharp peaks

amorphous - broad trace with no distinct sharp peaks

8

Polymorphism is..
This is possible because..

when crystalline solids can take many different shapes/arrangements

this is possible because of multiple functional groups

9

Polymorphism doesn't affect...

intrinsic properties
e.g. molecular weight/ pKa

These will be the same no matter the arrangement.

10

Examples of polymorphism

Graphite is a polymorphic compound of Diamond.

11

What is Transformation?

One solid form can spontaneously convert to another depending on favourable environmental conditions.

12

Most stable and least stable solid structure?

Most - crystalline

Least - amorphous

13

Most soluble and least soluble solid structure?

Most - amorphous

Least - crystalline

14

Stability depends on...

environmental conditions

15

The greater the stability, the lower the...

solubility

16

An example of a drug who presents polymorphism:

Paracetamol
Form 1
stable, easy to crystallise but hard to compact

Form 2
metastable, difficult to crystallise but easy to compact

17

What happens with the forms of Chloramphenicol?

mixture of alpha and beta crystals where b form is more water soluble and has greater oral bioavailability.

the more beta = absorbed quickly and more effective.

18

What happens to the Ritonavir in the capsule?

A new crystal type has been formed - different arrangement that they had never seen.

19

Properties that vary between polymorphic forms: (4)

density

melting point

solubility

compatibility