PHARMACEUTICAL MICROBIOLOGY Flashcards
types of infective agents
- prions
- viruses/viroids
- bacteria (unicellular, prokaryotic cells) - eubacteria
- fungi (eukaryotic cells)
prion
misfolded protein that can interact with a normal protein molecule causing the normal protein to undergo a conformation change so that is too becomes a prion and ceases its normal function
prions and sterilisation agents
prions are extremely resistant to conventional sterilising agents, and need to be eliminated from the pharmaceuticals supply chain ‘at source’
viruses
- no cellular structure but are particles composed of nucleic acid surrounded by proteins and sometimes a lipid envelope with associated glycoproteins
- incapable of independent replication (must infect other organism to reproduce)
viroids
similar to viruses but infect plants
2 main classifications of biological cells
prokaryotes
eukaryotes
crucial difference between prokaryotes and eukaryotes
eukaryotes bacteria possess a true cell nucleus where the chromosomes are separated from the cytoplasm by nuclear membrane, where as prokaryotic cells have no nucleus and normally possess a single chromosome
groups of bacteria
- archaea
- eubacteria (stained gram + or -)
- aerobic/anaerobic bacteria
fungi
- eukaryotes
- non photosynthetic plants
- found as yeast
- moulds with mycelium or filaments
saprophyte
live on dead material
parasite
live in a host
pathogenic
live in, and damage, a host
opportunistic pathogen
where the organism takes advantage of an opportunity not normally available, such as a weakened immune system
resistance in bacterial ‘spores’
spores are more resistant than normal cells to chemical agents and high temperatures
sterile products
where you break a barrier, or treat a sensitive membrane (drug products, medical devices, others like surgical gloves etc.)
sterilisation in the pharmaceutical supply chain
the design of the product needs to be sterile, such that is stays that way for the rest of the supply chain
sterilisation methods
- heat (dry - oven)
- heat (steam/wet - autoclave)
- radiation (gamma rays/high energy electrons)
- gases (ethylene oxide, hydrogen peroxide, formaldehyde)
- filtration
sterilisation
the process of removing or eradicating all the microorganisms in a drug product
sterilisation by moist heat (steam or autoclaving)
- kills micro-organisms by transfer of heat energy of saturated steam
- 121 degrees Celsius, 30 apsi, for >15 min
- temp/pressure, steam quality, atmospheric gases critical
- cycle and load validation
sterilisation by dry heat
- kills micro-organisms by oxidation
- 160 degrees celsius for 2 hours, 170 for 1 hour
- depyrogenation at 220 degrees for >4 hours
sterilisation by filtration
- removes micro-organisms using filters with 0.2 micrometer pore sizes
- ‘capsule filters’: often using 2 in sequence for redundancy
- filters are tested by ‘bubble point’ after use for integrity
minimum contamination level of a sterile product
< 1x10^6
sterility testing
filtration
- drug solution filtered through two 0.2mcm membranes to retain bacteria and broth added
direct inoculation
- sample of drug solution added directly to broth
pyrogen
- cell wall components (liposaccaharide) from Gram negative bacteria are exogenous pyrogens and cause high temp fevers
- viable bacteria are not needed
- the bacterial liposaccharides activate an immune cascade which include endogenous pyrogens
what is a biopharmaceutical?
- also known as biological medicinal product
- any pharmaceutical drug product manufactured in, extracted from, or semi-synthesised from biological sources
examples of biopharmaceuticals
vaccines
blood/blood components
allergenics
somatic cells
gene therapies
tissues
advantages of biopharmaceuticals
- high specificity
- reduced side effects
- difficult to reproduce/copy, protecting manufacturers
biological v small molecules challenges
- complex production process
- costs (of setup)
- cost to patients
- cold supply chains (tertiary structures)
- public concerns over source materials
- IV products (sterile, need trained staff)
depyrogenation
- removes/destroys pyrogens
- most prevalent pyrogen: bacterial endotoxins found in the outer cell walls of gram-negative bacteria