Christy (characterisation of medicines)

Question 1

Characterisation of an organic molecule

Answer 1

• Proton, carbon and DEPT NMR experiments
• Infrared- identifies/confirms which functional groups are in the compound
• UV/Vis
• Mass spectrometry- HRMSESI (High Resolution Mass Spectrometry Electro Spray Ionisation)
• Elemental analysis- burn known weight of powder, machine captures gas and gives % values of C, H, S, N. Work out %O by difference. Must be used with melting point.
• Melting point (purity measure not greater than 3 degrees C)

Question 2

Determination of purity

Answer 2

Find molecule formula.
Find molecular weight.
Work out molecular weight value for C, H, and O.
Divide each by lowest molecular weight value.
Multiply by 100 to find percentage.

Question 3

Can you use the same techniques for characterisation of dosage forms?

Answer 3

No- methods will vary depending if material is a solid, semi-solid or liquid.

Question 4

Rheology

Answer 4

The science of deformation of material.
Can plot applied stress (y-axis) against sheer rate (x-axis).
- Plastic (sheer thinning)- viscosity decreases with more sheer force.
- Pseudoplastic- viscosity increases when force is applied but more like sheer thinning on the graph.
- Newtonian flow- no change in viscosity no matter how much sheer occurs.
- Sheer thickening- viscosity increases with sheer rate.

Question 5

How do we know a molecule is actually testosterone?

Answer 5

Test functional groups
NMR
- 1HNMR
- 13CNMR
DEPT- distortionless enhancement of polarisation transfer
- differentiate between different types of carbons depending on what group of hydrogens are attached e.g methyl groups (CH3). methylene group (CH2), methine (CH), quaternary carbon (C)

Question 6

Pharmacopeias

Answer 6

British pharmacopeia (BP)
European pharmacopeia (EP)
United States pharmacopeia (USP)

Can find drugs monograph- analyse formulation of each drug.

Use calibration curve
HPLC- high performance liquid chromatography