Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PM3B > biologics > Flashcards

biologics Flashcards

1
Q

what are mAbs

A

proteins
Therapeutic mAbs have been developed to block signals, kill cells, and activate receptors
A single rearranged antibody is selected that binds to desired antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is antigen?

A

Antigen = something bound by an antibody

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is antibody?

A

Antibody = molecule made by B lymphocytes that binds to an antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is “Polyclonal antiserum”

A

serum from animal immunised against an antigen (e.g. antivenom)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is “Monoclonal Antibody” “mAb”

A

= single antibody molecule against a single antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

antivenom vs/to mAbs

A

antivenom
- mixture of all antibodies
horse protein
made in animals
made by animal immune response

mAb (clever molecular biologist)
-only one antibody
-human protein
-made in bioreactor
-engineered by molecular biologists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

examples of therapeutic mAbs

A

Mouse/rat monoclonal antibody

Mouse & human antibody DNA mixture- Chimeric

Human antibody with binding site from mouse mAb- Humanized

Human mAb (made from human

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the 2 main classes of therapeutic protein
examles

A

proteins and peptides
monoclonal antibodies

p and monoclonal
Insulin - Herceptin
Growth hormone- Rituximab
Clotting/blood factors - Infliximab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What makes mAbs special?

A

mAbs are proteins- therefore unstable (structural, chemical)
BUT the antibody molecule is far more stable than other therapeutic proteins

Serum half-life far higher than most other therapeutic proteins- antibody molecule can last weeks!

Molecular weight higher than most other therapeutic proteins – bioavailibilty very limited except by i.v.

Dose and route administered differ:
High activity, potent therapeutic proteins- low doses, s.c.
mAbs - higher doses, i.v. infusion (but some s.c. e.g. Humira)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are mAb doses so high?

A

Molecular weight 100-1000x higher than small molecule
Therapeutic mechanism of action

Block (Herceptin- blocks growth factor receptor
Kill (Rituximab- kills leukemia B cells

Example of dose
e.g. around 500mg Rituximab infused at a rate of 50-400mg/hour
Treatment: weekly for 4-8 weeks
(contrast with insulin: 1 Unit is 45micrograms; high dose of 10 Units would be 0.5mg)

High cost:
Laboratory antibodies cost £100 per mg!
Rituximab: £873 for 50ml of 10mg/ml (i.e. 500mg)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

formulation of mAbs

A
  • high conc of mab
    -Excipients added to reduce aggregation
    Lyophilised mAbs must be dissolved to produce solution for injection;
    Once dissolved, short storage life

Future advances:
- pre-filled syringes
- reduce injection volumes (very high protein concentration)
- ‘domain’ mAbs made from subunits of whole antibody

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is damage caused by

A

damage is caused by adaptive immune mechanisms
and
no hazard can be identified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how can you classify by source of antigen

A

External = hypersensitivity
Internal = autoimmunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how can you classify by effector mechanism causing immunopathology?

A

Antibody type
T cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the classifications of hypersensitivity

A

class - effector mechanism - example
I - IgE antibody on mast cells - Hayfever, asthma, anaphylaxis

II- IgM and IgG antibody mediated cell killing- Mismatched blood transfusion, Penicillin, Haemolytic anemia of the newborn

III- IgG antibody immune complexes- Serum sickness, long-term mAb use

IV- T cells- Contact dermatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Factors that affect immunogenicity:

A

Type of biologics (proteins especially likely target)
Sequence origin (human safer)
Origin of protein (mammalian cells best)
DELIVERY
e.g. Erythropoetin: subcutaneous = high risk
FORMULATION
Aggregation especially critical
Aggregation driven by denaturation, surfaces, silicone oil, incorrect storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are biomacromolecules

A

Biomacromolecules used as drugs – rather than small molecules

check one note

17
Q

what are biomacromolecules

A

Biomacromolecules used as drugs – rather than small molecules

check one note

18
Q

what is a biologic

A

created by either a microorganism or mamalian cell
large complex molecules, most of which are proteins or polypeptides
activity may be affected by the cell system in which it is produced, the fermentation media, or operating conditions.

have a complex production process that tends to yield small quantities.
Biologics are often extremely sensitive to physical conditions (temperature, shear forces, chemical phase, and light) and enzymatic action.
They usually require complex bioassays for batch release and stability assessment

19
Q

what is biosimilar

A

biological function similar to ‘original approved drug’
Have to prove functionally equivalent by clinical evaluation

Generic: is chemically identical to branded drug

20
Q

what is he difference between traditional small molecules and biologicals

A

small moleculw - aspirin
biologicals - monoclonal antibody - flu vaccine

21
Q

why is the manufacture so complex for biologics and what is the manufacturing requirements

A

Due to:
Fragility of biological macromolecules
Sensitivity of the living cells that produce biologics
Often heterogeneous in the molecules and/or polypeptides present
Impurity profile that depends on the processes used to make and test each batch.

Therefore complex manufacturing requirements for
fermentation
aseptic processing
storage
testing

22
Q

4 categories of biologics examples and use
why use biomacromolecules

A

gene therapy - nuceleic acid (gendicine) - only way to modify patients geonomes

proteins and peptides - Insulin, Growth hormone and Clotting/blood factors - Closest replacement of endogenous proteins

monoclonal antibodies - Herceptin, Rituximab and Infliximab - Ability to bind any antigen target Range of effects Common formulations and delivery for all mAbs

vaccines - Mixture of lipids, polypeptides, nucleic acids (Influenza vaccine, BCG tuberculosis vaccine and Hepatitis B vaccine) - Only way to protect individuals and populations from infectious diseases

23
Q

General ‘pharmaceutics’ challenges for biomacromolecules
what are the complexities

A

Complexity of biologics higher than typical drugs
- molecular complexity
-functional complexity
-complex composition
more to ho wrong, more expensive to manufacture

Instability of biomacromolecules inherent due to biological origin

Availability often limited by large molecular size

Immunogenicity immune response to drug (hypersensitivity) can lead to loss of efficacy and more serious adverse effects

24
Q

Why are Biologics typically so unstable?

A

Instability of biomacromolecules inherent due to biological origin

Conditions must be compatible with biological molecules
BUT this means they are good food for microbes – or atleast good environment
Also, many reactions of biological molecules are thermodynamically favourable in these conditions
Finally, almost all Biologics contain proteins- and proteins are relatively unstable

25
Q

Mechanisms of protein instability

A

1) Proteins have three-four layers of vital structure
2) Basic polypeptide chain is susceptible to a range of degrading reactions with water and oxygen
3) Many changes are irreversible

physical instability and chemical instability like oxidation , hydrolysis, isomerism, racemisation
ALL proteins are unstable

26
Q

Importance of protein structure

A

Denatured proteins – won’t work, often irreversible

27
Q

Biomacromolecule instability: Similarities with food

A

Chemical’ storage different from ‘food’ storage
Salt/cleaning chemicals vs protein rich foods
Small molecule drugs vs biomacromolecules

Microbial contamination is the major problem for wet foods
Another is ‘disintegration’ or ‘degradation’ of fresh foods

food solutions
Canning: autoclave (steam sterilise) and seal aseptically
Drying: air drying (biltong), freeze drying (fruit
freezing: peas

biologics solution
Filter sterilise and seal aseptically
Works for some (must certify cold-chain storage)
Works for some (expensive; need for reconstitution)

28
Q

formulation methods used for biolgics and how it works

A

sterilisation - prevent microbial growth
preservatives - prevents microbial growth
stabilisers - Reduces chemical and physical instabilities of proteins
Fridge- Reduces rate of chemical and microbial spoilage
freezer - Reduces rate of chemical and microbial spoilage
Lyophilisation- Prevents aqueous phase degradation (hydrolysis etc.) and microbial growth

29
Q

Lyophilisation- Freeze-drying details
advantages and disadvantages
and why

A

+ Stabilises protein - Proteins are susceptible to hydrolysis and oxidation- and other chemical reactions. Removal of water prevents these reactions. Also prevents microbial spoilage, although

+ Can increase shelf life significantly - Typically freeze-dried proteins can be stored at room temperature or higher- although for safety, usually kept in fridge

  • Freezing damage- Freeze-drying is the most common way to remove water from biological materials- but freezing creates ice crystals, which can damage protein

-expensive - Slow and complex manufacturing process requires large and highly specialised equipment- pharmaceutical grade freeze-dryer

30
Q

how does lyophilisation work

A

Freeze protein plus excipients in vial (without lid!)
(ideally fast and controlled)

Powerful vacuum applied to frozen material

Ice is sublimed- i.e. turned into water vapour – very slowly without melting

Finally, freeze dried protein (plus excipients) left behind as a “cake”

30
Q

how does lyophilisation work

A

Freeze protein plus excipients in vial (without lid!)
(ideally fast and controlled)

Powerful vacuum applied to frozen material

Ice is sublimed- i.e. turned into water vapour – very slowly without melting

Finally, freeze dried protein (plus excipients) left behind as a “cake”

31
Q

Formulation of biomacromolecules: excipients

A

Excipients can interact with and alter function of protein

Solubility-enhancers – not needed for many proteins. Note: protein solubility lowest solubility at i.e.p.
Detergents – e.g. polysorbate 20 or 80, albumin. Prevent interface-induced unfolding
Buffers – phosphates, citrates
Preservatives – e.g. phenol, benylalcohol
Antioxidants – e.g. ascorbic acid, sulphites, cysteine
Lyprotectants – Non-reducing sugar added during removal of water to protect structure of protein.
Osmotic compounds: ensure isotonicity (sugars, NaCl)

32
Q

Delivery of biologics

A

Availability often limited by large molecular size
1) Permeability through epithelia
2) Access to tissues from blood vessels
3) Cell membranes (although drug target usually not within cells)
Common problem- oral delivery unsuitable
Different route for each class/example
Route typically used is dictated by the characteristics of each class

32
Q

Delivery of biologics

A

Availability often limited by large molecular size
1) Permeability through epithelia
2) Access to tissues from blood vessels
3) Cell membranes (although drug target usually not within cells)
Common problem- oral delivery unsuitable
Different route for each class/example
Route typically used is dictated by the characteristics of each class

33
Q

In common
Biomacromolecules won’t pass through epithelia or membranes
Digested by gastric and intestinal components
Oral biomacromolecules = food!

typically cannoy ise oral delivery

A
34
Q

dleivery for each of the 3 cateogories

A

gene therapy

proteins and peptides - Injected (im, sc, id), inhaled- TYPICALLY potent; low, precise doses needed, Overdose can cause problems
Usually short half-life and often high frequency

monoclonal antibodies -Injected: IV infused or Subcutaneous
TYPICALLY low specific activity; high doses needed
Overdose unlikely
Long half life
often low frequency

vaccine : Injected (im, sc), also oral
Must be delivered to lymph nodes where immune response is generated

35
Q

dosage for biologics

A

Usually are injected or infused.
ROUTE AND DOSE DEPENDS ON TYPE
Potency is more difficult to quantify for biologic agents
Monitoring is a key component of early therapy.

New modes of administration eg transdermal vaccines

36
Q

Delivery of therapeutic proteins and peptides

A

Depends on exact therapeutic BUT often:
High activity
-Control of dose vital
Fast clearance following iv injection- serum half life short
-Typically im/sc
-Better for patient
-’Depot’ effect

If protein too large - subject to lymphatic drainage
Bioavailability less than 100%

BUT: many other experimental routes of delivery explored including: Inhaled, transdermal, oral

37
Q

Delivery of monoclonal antibodies

A

Depends on exact drug/ condition BUT typically:

High dose needed- blocking or killing
High injection volume- can be too high for subcutaneous
Serum half life very long

Typically intravenous or [in some cases, if dose can be achieved] subcutaneous
38
Q

Immune system evolved to recognise:

A

Peptides (T cells)
Structures (B cells)

39
Q

Gene therapy

A

Similar or different from other ‘bio’ therapeutics?
-Great promise, but little actual clinical success
-Fundamental risk of mutagenesis by gene insertion

Large field of research, major progress in last 20 years
Also major advances in last 5 years
Still totally unique approach to medicine
But yet to find the ‘killer application’

Only two licensed therapies worldwide
Gendicine (head and neck cancer, p53 adenovirus)
Glybera (rare enzyme deficiency) http://www.uniqure.com/products/glybera/

PM3B (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions