Chemistry of Drugs Week 19

Question 1

What is the difference between a risk assessment and COSHH?

Answer 1

a risk assessment is used for PROCESSES e.g. use of autoclave, COSHH is used for harmful substances

Question 2

How is COSHH approached (5 factors)?

Answer 2

1. identify which harmful substances may be present
2. decide how people might be exposed and harmed
3. look at measure to put in place to prevent harm
4. provide information, instruction and training
5. provide health surveillance in appropriate cases

Question 3

What are the 3 main steps to follow in a COSHH assessment?

Answer 3

1. identify the hazards
2. decide who might be harmed and how
3. evaluate the risks and decide on precautions

Question 4

How can you find out which substances are harmful?

Answer 4

reading product labels, safety data sheets (SDS) and suppliers catalogue information

Question 5

Where is non-toxic aqueous solvent disposed of?

Answer 5

drains

Question 6

Where is halogenated organic solvent waste disposed of?

Answer 6

halogenated bottles

Question 7

Where is non-halogenated organic solvent waste disposed of?

Answer 7

non-halogenated bottles

Question 8

What is disposed of in the glass bins?

Answer 8

glass materials, ceramic ware, cover slips, microscope slides, test tubes (uncontaminated), pasteur pipettes, thermometers

Question 9

What is disposed of the sharps bins?

Answer 9

razor blades, scalpel blades, syringes with needles, lancets, pins, sharps

Question 10

What goes in the biohazard bins?

Answer 10

ANY material that has been in contact with biological agents - blue roll, gloves, plastic pipettes, tips, cuvettes

Question 11

What goes in the special waste?

Answer 11

crude oil, mercury etc - must be clearly labelled with component, concentration, volume and hazards and sealed

Question 12

What goes in the general waste?

Answer 12

ALL UNCONTAMINATED waste - blue roll, bungs, cotton wool, plastic tubing etc

Question 13

What must you contact the technical team for?

Answer 13

special material including solvent bottles, hard plastic, scrap metal etc

Question 14

Which functional groups are particularly susceptible to degradation by hydrolysis?

Answer 14

esters and amides

Question 15

What is needed for the synthesis of drugs?

Answer 15

REACTIVE functional groups

Question 16

What do we tend to NOT have in drug molecules once made?

Answer 16

reactive functional groups

Question 17

Why do we not want reactive functional groups in drug molecules?

Answer 17

we are nucleophilic, so don’t want electrophilic functional groups attacking enzymes, proteins, DNA etc

Question 18

By which 2 processes do drugs usually degrade?

Answer 18

1. photolytic degradation
2. hydrolysis

Question 19

What are the general steps of photolytic degradation (generally oxidation)?

Answer 19

1. the molecule absorbs a photon from the IR, visible or UV light spectrum
2. this causes the drug molecule to go from its ground state to an excited state
3. the drug molecule can then spontaneously decompose or react

Question 20

What are 2 examples of drug types that are susceptible to photo decomposition?

Answer 20

various corticosteroids and antimycotics

Question 21

How is photolytic degradation avoided?

Answer 21

use of amber glass bottles, blister packs, fridges etc, use of a physical quencher

Question 22

define physical quencher

Answer 22

a compound that causes physical decay of the excited state before decomposition occurs

Question 23

How is photolytic degradation a positive?

Answer 23

it can be used to reduce the effect of pharmaceuticals on the environment in waste water etc

Question 24

How can pharmaceuticals be eliminated from the environment?

Answer 24

photo-assisted wastewater treatment methods

Question 25

Which groups are susceptible to hydrolytic degradation?

Answer 25

esters and amides - including their cyclic counterparts lactones and lactams

Question 26

define lactone

Answer 26

a cyclic ester

Question 27

define lactam

Answer 27

cyclic amide

Question 28

Why do paediatric penicillin suspension need to be kept in the fridge?

Answer 28

1. once made up, they are aqueous suspensions 2. water molecules can hydrolyse the strained lactam ring 3. refrigeration reduces hydrolysis

Question 29

Why is the nitrogen bond in penicillin not very reactive?

Answer 29

its lone pair overlaps with the C=O bond due to resonance

Question 30

What are repackaging of a medication, involving removal from its primary packaging examples of?

Answer 30

off-label of illegal use of a medicine

Question 31

Why is this off-label use?

Answer 31

removal from its primary packaging invalidates the stability guarantee of the manufacturer

Question 32

What is the MCA stability tool (for multi compliance aids)?

Answer 32

information on stability for tablets and capsules to help create MCAs for patients

Question 33

What does a green label for MCA stability mean?

Answer 33

the drug is okay to be put in an MCA

Question 34

What does a yellow rating on the MCA stability tool mean?

Answer 34

special measures are needed for that drug to prevent degradation

Question 35

What does a red rating on the MCA stability tool mean?

Answer 35

do NOT use this drug in MCAs

Question 36

What are the potential issues for use of proteins/biologicals as drugs?

Answer 36

1. hydrolysis of the backbone 2. oxidation of susceptible side chains e.g. cysteine and methionine

Question 37

What could oxidation of cysteine result in?

Answer 37

formation of a disulfide bond between two cysteine side chains resulting in protein aggregation

Question 38

What could oxidation of methionine result in?

Answer 38

oxidation to methionine sulfoxide

Question 39

Which 2 main factors does the drug design process involve?

Answer 39

1. pharmacological properties 2. drug-like properties

Question 40

What do pharmacological properties include?

Answer 40

interactions, Lipinski's rules

Question 41

What do drug-like properties include?

Answer 41

affinity and efficacy

Question 42

Why are protein side chains important?

Answer 42

the nature of the groups influences how they react with functional groups on drug molecules

Question 43

What does drug design rely on?

Answer 43

1. pharmacological properties (good interactions between ligand and target) - hydrogen bonds, ionic bonds, lipophilic interactions etc 2. having good drug-like properties - not metabolised too quickly, can reach site of action, high affinity and efficacy