Assuring Quality of Biological Medicinal Products Flashcards
What are biological medicinal products?
- Biologicals are large molecules produced in, or extracted from living cells or systems
- Biologicals have complex structures and are more difficult to characterize (& to copy)
- Biologicals are heat-sensitive and susceptible to microbial contamination.
What are the different types of biological products?
- Traditional Biological Medicinal Products (TBMP)
- Biological products extracted directly from human and animal tissues.
- Examples of TBMP include blood components – albumin, plasma, platelets (human) and rabies vaccine (dogs), heparin (pigs) and antivenoms (snakes). - Biotechnology-Derived Medicinal Products (BDMP)
- Newer biological products are now produced in living cells (microbial, mammalian)
- Examples of BDMP include human insulins, HGH & EPO made via recombinant DNA (rDNA) technology), and monoclonal antibodies mde via hybridoma technology.
What is the definition of biotechnology?
the use of living cells/organisms, or their products to modify human and animal health, mankind and his environment.
Biotechnology Medicinal Products: What are the differences between microbial (bacteria, yeast) versus mammalian substrates?
Speed of cultivation: faster for microbial, slower for mammalian
Where are the proteins/products secreted: proteins secreted within cells for microbial, products secreted outside of cells for mammalian cell substrates.
Amount of yield: lower yield for microbial cell substrates due to more difficult purification, higher yield for mammalian substrates due to less complicated purification.
Difference in complexity of proteins: lower yield for microbial cell substrates due to more difficult purification. Higher yield for mammalian cell substrates due to less complicated purification.
Safety of cell substrates: microbial cell substrates are relatively safe as biotechnology products, mammalian cell substrates have many safety issues
What are the initial safety concerns of mammalian cells?
- Transformed mammalian cells using hybridoma technology are “immortal” and potentially oncogenic (carcinogenic)
- Possible contamination of protein product with potentially oncogenic hybridoma DNA
What are the critical GMP and QA issues in manufacture of biotechnology-derived medicinal products?
- Assuring genetic stability of cell substrates with plasmid/vector and gene of interest
- Absence of (biological and chemical) impurities from nutrient media and starting materials
- Assuring quality and yield through consistent manufacturing processes
- Absence of inherent endogenous viruses
- Elimination of residual DNA from the hybridoma of mammalian cell
- Slight changes to manufacturing processes can have major impact on quality, safety and efficacy of product.
- Each biotech-derived medicinal product is unique and difficult to replicate identically, hence the term biosimilar is used.
» Biosimilar: a biological product which is highly similar to, and has no clinically significant differences from the innovator product
List the different components of the cell banking system
- Control of cell banks: master cell bank (MCB)
- Working Cell bank (WCB)
- Types of tests conducted at cell banks (MCB & WCB)
- Inspection of Cell Bank System
Describe the process of the control of cell banks: master cell bank
- Contains well-characterized cells derived from a specific cell line.
- Cells are stored frozen under defined conditions, e.g. liquid nitrogen (-196 degree Celsius)
Describe the working cell bank (WCB)
- Used to provide “working” cells for manufacturing
- WCB is derived from one or more containers of MCB and must be tested before use.
- Tests are usually less than those conducted at MCB.
State the types of tests conducted at cell banks (MCB
- Tests for genetic stability
- Tests for endogenous viruses inherent mammalian cell lines
- Tests for adventitious viruses introduced during sampling or cell expansion
- Tests for residual DNA
Describe the various processes of the inspection of cell bank system
- Documentation of Cell Origin & History
- Evidence of well-characterized cell line (via QC tests)
- Records of QC tests conducted on cell banks - Management of Cell Banks (MCB & WCB)
- Appropriate storage (temperature) condition
- SOP & records on replacement of liquid nitrogen
- Stock control/reconciliation of ampoules/vials of cells
- Cross-contamination measures taken during sampling, QC testing and cell expansion
- Restricted access to authorized personnel
- Maintenance and back-up arrangements - Contract Testing Laboratories
- Availability of comprehensive written contract
- Roles and responsibilities of contract acceptor and giver
What is cell cultivation (fermentation/culture)?
- Cell cultivation may be referred to as fermentation (when microbial cells are cultivated in fermenter), or cell culturing (when mammalian cells are cultivated in bioreactor).
- Cell cultivation is used as reference point to categorize biopharmaceutical processes
What are the different upstream and downstream processes in cell cultivation?
Upstream processes
- Cell Banking
- Cell Expansion & Scale up
- Cultivation
- Harvesting
Downstream processes
- Primary purification (affinity chromatography)
- Viral inactivation (low pH, detergent)
- Secondary purification (column chromatography)
- Viral removal (nanofiltration)
- Batching and storage of bulk biological API
- Formulation, filling and packaging, QC of finished biological product
What are the growth requirements for bacteria?
Physical:
- Temperature
- pH
- Osmotic pressure
Chemical:
- Water, oxygen
- Carbon, nitrogen, sulphur, phosphorus
- Trace elements
- Organic growth factors
List and describe the different types of fermentation for bacterial cell growth
- Batch Fermentation
- Closed system of bacterial cells and media, oxygen is continuously added.
- Toxic metabolites accumulate
- Bacterial cell growth curve: lag, log, stationary and decline phases.
- (+): chance of contamination is minimal
- (-): low product yield (not economical) - Continuous fermentation
- Open system of bacterial cells and media, fresh sterile media added continuously
- Bacterial cells are always growing in log phase – steady state growth
- (+): very high product yield (very economical)
- (-): chance of contamination is higher - Fed-batch fermentation
- Media added and waste products removed at period intervals; semi-closed system
