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PM2B: Journey Through the GI tract > Nancy: Sterilisation > Flashcards

Flashcards in Nancy: Sterilisation Deck (18):

Why do we sterilise pathogen contamination (salmonella contamination)

1. Microbes harm patient and can cause infectious disease

2. Provides opportunistic infection


Why do we sterilise microbial spoilage (like milk)?

1. Microbes damage product

2. Degrade API

3. Make dose unpalatable


What sort of order of growth is microbe growth?

First order (doubling time)


What is the order of sterilisation of microbial growth?

1. Death of microbes follow 1st order kinetics

2. 1000 microbes (0 minutes)

3. 100 microbes (1 minute)

4. 10 microes (2 minute)


What is the order of sterility in different forms of pharmaceutical products?

1. Parenteral injection is a major infection hazard

2. Application to sensitive sites like ocular, ears and creams

3. Tablets (not so sterile)


What is the sterility assurance level?

1. A level of sterility the pharmacopoeia requires for terminally sterilised products of 10-6 or better

2. Only 1 microbe should be surviving in 1 million products


What is absolute sterilisation?

Absolutely no microbes


How do you do sterilisation testing?

1. One sample is taken

2. Either liquid, swab or filtrate

3. Add to culture medium

4. Wait for 14 days any growth at all? if not it's sterile


What are the 5 sterilisation methods?

1. Heat

2. Filtration

3. Chemical

4. Irradiation

5. Gas


Describe how steam sterilisation works, the equipment and what it's applied on?

1. Steam under pressure

2. Autoclaves widely used: low cost, certified sterilisation
(121 degrees, high pressure for 15 to 30 minutes)

3. Has high latent heat of vapourisation: transfer heat really well to the surface it condenses to

4. Hydrolysis of proteins in particular, enzymes

5. Application: Equipment and liquids


Describe how dry sterilisation works, the advantages and disadvantages?

1. Dry oven: 170 degrees for 2 hours

2. Dry heat kills by oxidation

3. Not suitable for liquids (dries them out), mainly used for lab glass ware, dental tools and surgical knives


Describe how filtration sterilisation works, what its mainly for and the equipment?

1. Used to sterilise heat sensitive materials such as ophthalmic solutions
head sensitive injectables

2. Membrane filters:
uniform pore size is VITAL
0.22 micrometers: Removes most bacteria- NOT VIRUSES
0.01- 0.1 micrometers: Retains all viruses and some large proteins

3. Industrial filters: Large cartridges, controlled pressure, continuous use


Describe how some examples of chemical sterilisation work?

1. Strong acids and bases (HCl and NaOH)

2. Phenols interupt bio membranes and denature proteins that are low to mid disinfectants

3. Alcohols denature proteins and dissolve membranes: Mid level disinfectants

4. Aldehydes: effect the cross link between biomolecules


Describe how the irradiation method of sterilisation works for UV and gamma rays?

1. Rapid surface sterilisation

2. Surface only absorbed by most material this weak penetration

Gamma rays:
1. Passes many materials deep penetration

2. Used to sterilise pre packaged products (in-situ)


Describe how the gas method of sterilisation works?

Mist and spray:
1. Rapid surface sterilisation

Ethylene Oxide:
1. Sterilisation of heat sensitive products

2. Highly flammable, toxic and carcinogenic


What are the conditions that influence the effectiveness of anti-microbial agents?

1. Types of micro-organisms (genera, species, strains and cells structure)

2. Concentration of micro-organsisms

3. Physiological state (age, growth medium)

4. Environmental conditions (pH, viscosity)

5. Temperature


What ar the three steps taken to produce sterile products?

1. Sterilisation- disinfection and killing

2. Aseptic Handling- keep it clean

3. Quality control and monitoring- spot the danger


What are the organisms of are hardest to kill via sterilisation?

Hardest to easiest to kill:
Bacterial spores
Fungal spores
Yeasts (spores and vegatative cells)
Gram negative bacteria
Gram positive bacteria