L6 Thermal Anal

Question 0

Thermal analysis methods measure

Answer 0

Heat exchange while heating or cooling a sample at a controlled rate

Question 1

All physical changes are accompanied by…

Answer 1

Heat exchange (deltaH)
Either to or from surroundings

Question 2

Thermal analysis tools used to characterise… 7

Answer 2

Melting point
Heat capacity
Kinetics of reaction
Kinetics of decomposition (shelf life)
Crystalline state of matter (polymorphism amorphous content,glass transitions, solvates/hydrates.
Purity and stability
Compatibility with excipients
J

Question 3

Six thermal analysis techniques

Answer 3

Thermomicroscopy
Thermogravimetric analysis (TGA)
Thermomechanical analysis (TMA)
Differential thermal anyalysis (DTA)
Differential scanning calorimetry (DSC)
Isothermal microcalorimetry (ITM)

Question 4

TGA stands for

Answer 4

Thermogravimetric analysis

Question 5

TGA measures…. As a function of….

Answer 5

Weight of a substance as a function of ramping temperature

Question 6

TGA Requires…

Answer 6

Vacuum mass balance with sensitivity of 0.1microg

This instrument is hermetically sealed to allow atmospheric pressure to be controlled

Question 7

TGA studies…and … of….

Answer 7

Stability and kinetics of drug decomposition

Question 8

TGA curve measures

Answer 8

Mass over temp

Question 9

Look at pictures of curves in book for TGA

Answer 9

.

Question 10

Three components of TGA machine?

Answer 10

Microbalance, sample and furnace

Question 11

Typical application of TGA…

Answer 11

Quantification of water loss

Question 12

DTA stands for

Answer 12

Differential thermal analysis

Question 13

DTA monitors….. and …. as….

Answer 13

Sample and reference as they are heated at a constant rate

Question 14

DTA graph shows …. Against …. To obtain ….

Answer 14

Delta T against time

To obtain a thermogram

Question 15

DTA provides…

Answer 15

Follow endo (heat absorbed) or exothermic transitions during a chemical process.
Provides only qualitative or semiqualitative method mor measuring calorimic data.

Question 16

Basic set up of DTA?

Answer 16

One heat source for sample and reference

Question 17

Heat flux DTA

Answer 17

One heat source for sample and reference.

Heat converted to power.

Question 18

Endothermic

Answer 18

Heat abosorbed.

Temp of sample is less than reference because it is taking in energy to fuel a reaction eg. Melting point transition.

Question 19

Exothermic reaction

Answer 19

Heat evolved
Temperature of sample cell is higher than that of the reference becuase a sample is giving out energy as a product of a reaction.

Question 20

Example of an exothermic reaction

Answer 20

Crystallisation

Question 21

Example of an endothermic reaction

Answer 21

Melting point transition

Question 22

DSC Stands for…

Answer 22

Differential scanning calorimetery

Question 23

how does DSC work?

Answer 23

Similar to DTA except erasure the amount of energy required to keep the sample at the same temperature as the reference.

Question 24

DSC is the preferred temperature ramping technique as....

Answer 24

Provides detailed info about physical and energetic properties of a substance.

Question 25

DSC provides qualitative or quantitative information

Answer 25

Quantitative

Question 26

DSC measures ..., .... and .... | As a function of .... and .....

Answer 26

Endothermic, exothermic and heat capacity changes as a function of Time and temperature.

Question 27

How does power decompendated DSC work?

Answer 27

DeltaT compensated for by varying heat to keep sample and ref at same temperature. Using platinum heat sensors

Question 28

DSC is plotted as...

Answer 28

Energy provided plotted as function of temperature the sample and ref are being raised to

Question 29

DCS has single/separate furnaces

Answer 29

Separate

Question 30

Area of the dip in a power over temp graph for DSC is equal to...

Answer 30

Enthalpy

Question 31

When a sample reaches melting it...

Answer 31

Remains at that temperature until all the sample has passed into the liquid state. Because if the endothermic process of melting.

Question 32

Heat flow

Answer 32

Is the energy required to keep the sample at the same temperature

Question 33

Heat flow is recorded with a sensitivity of

Answer 33

+/-0.1microcalories/s

Question 34

Melting of crystals is a .... Order reaction

Answer 34

First

Question 35

Melting is exo/endothermic

Answer 35

Endothermic ( the sample takes in the molar heat of fusion)

Question 36

ISM stands for

Answer 36

Isothermal micro calorimetry

Question 37

Principle of IMC is to monitor.....

Answer 37

Heat into/out of a sample cell, from/to a sink

Question 38

Sink is held isothermically with and accuracy of .... Improve to .... By...

Answer 38

+/- 10^-4 Use a reference cell to correct for variations Brings it down to +/-10^-6

Question 39

Output is ... As a function of time

Answer 39

Change of heat as a function of time

Question 40

ITC does/does not use temperature ramping

Answer 40

Does not

Question 41

ITC examines....

Answer 41

Solid state stability of tablets Product interaction with stability studies Wetting of drugs Measuring enthalpy of immersion Crystal properties (amorphous crystalline transitions)

Question 42

Advantages of ITM

Answer 42

- DTS & DSM to determine rate of decomposition requires extrapolation of data to storage temperatures - ITM sensitivity can measure kinetics of product degradation in or,al storage conditions. - non distructive - not sample treatment required - real time quantitative data - obtains kinetic and thermodynamic data - can be used to monitor and physical, chemical or biological process

Question 43

ITM has .... Greater sensitivity than DCS

Answer 43

10,000

Question 44

Disadvantage of ITM

Answer 44

Need large sample size. 1000mg. | DSC 10mg

Question 45

Thermal studies allow....

Answer 45

- characterisation of drug substances and formulations in qualitative and quantitative manner - allow optimisation of formulations - save time on stability studies - can be used for rate/mechanism/thermodynamic characterisation studies

Question 46

t/F Thermal analysis is In conjunction with other preformulation methods

Answer 46

T

Question 47

Crystallisation is endo or exo

Answer 47

Exo - sample is giving out energy

Question 48

Melting point transition is endo or exo?

Answer 48

Endo - sample is taking in energy to fuel reaction

Question 49

What valuable info do we get from therm anal 2

Answer 49

properties of materials and formulations. | An indication of a product stability and its interactions