Preformulation

Question 1

what is a crystalline structure

Answer 1

a solid in which particles are arranged in a pattern that repeats periodically in 3D

Question 2

What are the properties of a crystal

Answer 2

sharp melting points and are thermodynamically stable

Question 3

What is a unit cell

Answer 3

The smallest repeating unit of a lattice

Question 4

What is a lattice

Answer 4

A 3D set of points showing the position of the components that make a crystal

Question 5

What are the 4 types of crystalline structure

Answer 5

salt, cocrystal, hydrate and solvate

Question 6

What is a salt

Answer 6

a crystal made up of 2 or more ions including the API. Held together by ionic bonds

Question 7

What is cocrystal

Answer 7

a crystal made up of 2 neutral molecules including the API held together by hydrogen bonds

Question 8

What is a hydrate

Answer 8

a crystal made of water and the api

Question 9

What is a solvate

Answer 9

A crystal made up of the api and a solvent that isn’t water

Question 10

What are three common solvents used in solvates

Answer 10

Methanol, ethanol and acetone

Question 11

What is polymorphism

Answer 11

when crystals have the same chemical composition but different internal structures

Question 12

Why is polymorphism important

Answer 12

Means that different solids can have different physical properties such as melting point, solubility and bioavailability.

Question 13

How do you analyse a crystals Structure

Answer 13

X ray

Question 14

How do you analyse a crystal is thermal behaviour

Answer 14

Melting point and heat of fusion

Question 15

How do you measure a crystals thermodynamic stability

Answer 15

Solubility, the more soluble the less stable

Question 16

What is an amorphous crystal

Answer 16

A solid without a long range regular occurring 3D molecular pattern

Question 17

What are the properties of amorphous solids

Answer 17

No sharp melting point and are thermodynamically unstable.

Question 18

Which has a faster dissolution

Answer 18

Amorphous solids

Question 19

Which is less stable

Answer 19

amorphous solids

Question 20

What happens to amorphous solids when heated

Answer 20

They turn from glass like state to soft and rubbery because the molecules get enough energy to flow

Question 21

What is the glass transition temperature

Answer 21

the temperature in which an amorphous solid turns from glass like to the soft rubbery state

Question 22

What are the stages involved when amorphous solids are heated

Answer 22

first it drops when it reached the glass transition temperature then returns to its original level where it peaks again in which the solid crystallises and then drops dramatically when it reaches melting point.

Question 23

What causes amorphous solids to turn into crystals

Answer 23

When kept on the shelf for too long. On form converts to another when thermodynamically favourable.

Question 24

What is gibs free energy

Answer 24

a value that tells you if a reaction is favourable

Question 25

What is the equation for the reaction of gibs free energy

Answer 25

ΔG= ΔH-S ΔS

Question 26

How is the the molecular structure of solids analysed

Answer 26

using XRD, x ray diffraction

Question 27

If ΔG is over 0 what does that mean

Answer 27

the reaction is thermodynamically unfavourable

Question 28

If Δg is below 0 what does that mean

Answer 28

The reaction is thermodynamically favourable.

Question 29

What is DSC

Answer 29

A way to measure how the physical properties of a sample change as the temperature changes

Question 30

What is DSC used for

Answer 30

To analyse the change in phase of solid

Question 31

What are emulsifiers

Answer 31

they’re substances that lower the surface tension between 2 immiscible substances allowing them to be mixed .

Question 32

What are viscosity enhancers

Answer 32

Substance which causes solution to be more fluid.

Question 33

What’s a hydrophilic emulsifier

Answer 33

A substance that produces oil in water solution