Biologics overview Flashcards
discuss why biological macromolecules are complex to manufacture
1) Fragility of biological macromolecules
2) Sensitivity of the living cells that produce biologics
3) Therefore complex manufacturing requirements for fermentation, aseptic processing, storage, testing
4) Often heterogeneous in the molecules and/or polypeptides present
- the Impurity profile that depends on the processes used to make and test each batch.
5) With biologics, the protein mix must be defined, and the active agent and supporting agents must be characterised ( the culture medium)
6) the manufacturing process is part of the patent and is subject to regulatory approval. (very difficult to copy)
what are the 4 different categories of biologics?
1) gene therapy
2) proteins and polypeptides
3) monoclonal antibodies
4) vaccines
explain why we use use biomacromolecules
1) gene therapy: Only way to modify patients genome
2) proteins and polypeptides: Closest replacement of endogenous proteins
3) monoclonal antibodies: Ability to bind any antigen target and produce a Range of effects
4) vaccines: Only way to protect individuals and populations from infectious diseases
state the 3 reasons why proteins are unstable
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
- chemical instability: oxidation, hydrolysis, disulfide exchange
3) Many changes are irreversible
4) physical instability - can precipitate, aggregate, adsorbed protein
there are a few methods we can use to deal with some of the problems with formulating biologics. below is a list of methods used, explain the purpose of each one.
1) Sterilisation
2) Preservatives
3) Stabilisers
4) Fridge
5) Freezer
6) Lyophilisation
1) Sterilisation- Prevents microbial growth
2) Preservatives- Prevents microbial growth
3) Stabilisers- Reduces chemical and physical instabilities of proteins
4) Fridge- Reduces rate of chemical and microbial spoilage
5) Freezer- Reduces rate of chemical and microbial spoilage
6) Lyophilisation- Prevents aqueous phase degradation (hydrolysis etc.) and microbial growth
Excipients can interact with and alter function of protein and are used in the formulation of biomacromolecules. Give examples and state the purpose of each of the following excipients:
1) Solubility-enhancers
2) Detergents
3) Buffers
4) Preservatives
5) Antioxidants
6) Lyprotectants
7) Osmotic compounds
1) Solubility-enhancers – not needed for many proteins. Note: protein solubility lowest solubility at the isoelectric point (i.e.p)
2) Detergents – e.g. polysorbate 20 or 80, albumin. Prevent interface-induced unfolding
3) Buffers – phosphates, citrates
4) Preservatives – e.g. phenol, benylalcohol
5) Antioxidants – e.g. ascorbic acid, sulphites, cysteine
6) Lyprotectants – Non-reducing sugar added during removal of water to protect structure of protein.
7) Osmotic compounds: ensure isotonicity (sugars, NaCl)
discuss the challenges with regards to the delivery of biomacromolecules
1) Biomacromolecules won’t pass through epithelia or membranes
2) Digested by gastric and intestinal components
outline the delivery of Monoclonal antibodies into the body
1) Depends on exact therapeutic but often intravenous
2) High dose needed- blocking
3) High injection volume- too high for sc/im
4) Availability after sc/im not ideal
5) Serum half life very long
outline the delivery of vaccines into the body
1) Typically im/sc injection
2) Immune responses occur within lymph nodes: injection needed for conventional vaccines
Biologics are potential immune targets. state which cells in the Immune system recognise biomacromolecules
1) Peptides (T cells)
2) structures (B cells)
what are the General ‘pharmaceutics’ challenges for biomacromolecules?
complexity, instability, availability (and immunogenicity)
