Biologicals 1

Question 1

What interactions affect protein folding and stabiliation?

Answer 1

Hydrophobic interactions
Electrostatic
H-bonding
VDW forces
Steric effects
Hydration
Disulphide bridges

Question 2

Deamidation of proteins is favoured at what pH?

Answer 2

pH 5 and above

Question 3

What AAs are potential sites for oxidation?

Answer 3

His, Met, Cys, Trp and Tyr

Question 4

Which peptide bonds are not stable?

Answer 4

X-Asp-Y

Question 5

What is Tm?

Answer 5

Temperature at which 50% of molecules are unfolded, usually 40-80degC

Question 6

Melting of proteins can lead to what?

Answer 6

Deaggregation

Question 7

Chemical reactions are more rapid at elevated or lowered temperatures?

Answer 7

Elevated

Question 8

What physical conditions affect proteins?

Answer 8

Temperature
pH
Adsorption
Salts and metal ions
Concentration
Interfaces

Question 9

What are the possible consequences of aggregation/denaturation?

Answer 9

Altered solubility
Hypo-potency
Hyper-potency
Off target binding
Patient may generate neutralising antibodies
No effect

Question 10

What steps in making proteins can go wrong?

Answer 10

Manufacture
Formulation
Sterilisation
Storage
Administration
Release
Adsorption
Circulation

Question 11

What is stability of proteins influenced by?

Answer 11

Choice of excipients
Storage conditions-liquid, forzen, lyophilised
Delivery route and vehicle

Question 12

Stability and PK of proteins can be altered by what?

Answer 12

Chemical modifications

Question 13

What gets added to most proteins when formulating?

Answer 13

Solubility enhancers
Antiabsorption and antiaggregation agents
Buffering agents
Preservatives and anti-oxidants
Lyoprotectants/cake formers
Osmotic agents

Question 14

sugars and some amino acids cause what?

Answer 14

Increased surface tension of water

Question 15

What do cyclodextrins do?

Answer 15

Suppress aggregation of proteins

Question 16

What are polysorbates thought to do?

Answer 16

Stabilise proteins, preventing denaturation and aggregation.

Question 17

What mechanisms do polysorbates use?

Answer 17

Preferential exclusion of solutes.
Acting as a chemical chaperone aiding protein refolding.
Binding to hydrophobic patches of proteins.

Question 18

Why do polysorbates form a detergent film in aqueous systems?

Answer 18

To limit protein exposure to air/water interface

Question 19

Polysorbates compete with proteins to what?

Answer 19

Adsorb to surfaces-glass, IV bags, tubing materials etc.

Question 20

Polyorbates can lead to what?

Answer 20

Protein aggregation and denaturation

Question 21

what residues are susceptible to reactive peroxides?

Answer 21

W and M

Question 22

What can help prevent reactive peroxides from polysorbates?

Answer 22

Antioxidants

Question 23

Which residues are susceptible to aldehydes?

Answer 23

K and N

Question 24

Formaldehyde an acetaldehyde cause contact allergies and are potential what?

Answer 24

Carcinogens