Aseptic Production 4 Flashcards
What is aseptic production?
• Manipulation of sterile ingredients or products • Using sterile equipment • Using appropriate techniques • Clean room environment -to maintain state of asepsis
Clean Rooms • Walls and ceilings
• Walls and ceilings
– Moulds most common flora
– Feed off the plaster
Clean Rooms
– Should be smooth, impervious and washable
– Generally clad with laminated plastic
– False ceilings common to contain air filtration systems and light fittings
– Electrical wiring, pipework etc should be installed in cavity wall and sealed flush to surface
What do clean rooms maintain?
asepsis
Clean rooms
• Floors and drains
– Floors flat, impervious to water and easy to clean
– Floor joints adequately sealed
– Floor : wall junction coved (curved laminated plastic)
– Surface must be able to withstand cleaning products
– There should be no open sinks or drains in the clean room
Clean Rooms • Doors, windows and fittings
– Must be fitted flush with the walls to prevent dust collecting
– Doors must be well fitting to prevent ingress by microorganisms
– Doors must be easy to open
– Windows for light only, not ventilation
– Fittings, such as door plates (not handles) must be easy to clean
Clean rooms
• EU Guidance gives four grades of air:
– Grade A: for high risk operations e.g. aseptic connections, filling
– Grade B: minimum background environment for grade A zones
– Grades C and D: less critical stages of aseptic production e.g. labelling, packing
Air Quality at rest
Maximum permitted number of particles/m3 equal to or above - At rest
0.5um A: 3520 B: 3520 C: 352,000 D: 3,520,000
5um A: 20 B: 29 C: 2900 D: 29,000
Air Quality in operation
Maximum permitted number of particles/m3 equal to or above - In operation
0.5um A: 3520 B: 352, 000 C: 3,520,000 D: not defined
5um A: 20 B: 2900 C: 29,000 D: not defined
Air supply
- Air introduced through HEPA filter
* 20‐35 air changes per hour (depends on room size, activity and number of operators)
What is a HEPA filter
dust trapping filter
• Different air flow patterns:
– Unidirectional
– Non‐directional
Unidirectional air flow
- Grade A and B
- air comes in and goes through two sets of HEPA filters
- have a curtain of air usually from a ceiling
- air forced to floor in room, becomes turbulent around people
- air extracted through vents and is pumped out of the room and is then re-circulated through HEPA filters
Non‐directional Air Flow
- Grade C and D
- where the air is usually drawn in from the outside rather than re-filtered, drops through a HEPA filter. Get very turbulent air. Don’t get a curtain and particles are more likely to be blown up than down
- Cheaper unit to fit
High‐efficiency Particulate Air (HEPA) filters
• Pleated fibreglass with large surface area (pleating allows air to flow through filter at a high rate so don’t get a blockage) • Exhibit – High flow rate – High particulate holding capacity – Low pressure drop across the filter
HEPA Filters remove..
- Remove large particles by inertial impaction (onto fibre glass and stay)
- Remove medium particles by interception (by the very fine needles of fibre glass)
- Remove small particles by Browninan diffusion (motion of the air itself that causes the particles to be filtered out)
- Must conform to BS5295
HEPA filters disadvantage
need cleaning and replacing regularly
HEPA filters - interception drawing
bounce over one fibre but hit another
Room Pressurisation
-to ensure particles leave room rather than enter
Clean rooms generally operate under positive pressure
– 10‐15 pascals above surrounding environment
– Prevents ingress of particles
– Multiple rooms have multiple pressure differentials
• Negative pressure (10‐15 pascals below surrounding environment) used if products deemed to be a risk to operators (used mostly for cytotoxic production - have to go from a dirty environment into a clean room then into negative pressure)
Laminar Air Flow Cabinets - 2 types
- Similar to fume hood, in a fume hood you are extracting air but in LAFC the air is being pushed into the cabinet
- Horizontal Laminar Air Flow cabinet
- Vertical Laminar Air Flow cabinet
Horizontal Laminar Air Flow cabinet
For products with no risk to operator e.g. TPN
• Open front
• HEPA filter in back of cabinet
- keep movements at minimum
Vertical Laminar Air
Flow Cabinet
• For products with some risk to operator e.g. Cytotoxic drugs • Perspex barrier • HEPA filter in top of cabinet -narrow operating window -unidirectional downward air flow
What environment does a laminar air flow cabinet have to be in?
LAFC has to be in Grade B environment in the background but Grade A inside LAFC
Isolators
- are closed boxes and are much more economical in terms of cost of environment and can be placed in grade D but isolator themselves are more expensive than LAFC
2 types of isolators
Type I
• Positive pressure
• Protects product from operator and aseptic process
• Used for non‐ harmful production – TPN, injections, eye drops
Type II
• Negative pressure (equivalent to vertical LAFC)
• Protects product from operator and process and protects operator from product
• Used for cytotoxics, BCG
How to tell difference between positive or negative pressure isolator
if positive gloves will push outwards, if negative will go into the isolator
Isolators - Half‐suit isolator
- Rigid or flexible film
- Type I or type II
- Allows the operator greater movement
- Generally used in large scale manufacture - not used in hospitals
Clean room clothing
- Prevents particulate contamination from the human body
- Must not shed particles or fibres
- Must be washable (for economic reasons)
- Must be sterilisable (usually autoclaving or radiation)
For autoclaving fabric needs to stand high temperatures
Maintaining Asepsis
• Operator conduct
• Good technique is essential
– Staff training, validation and revalidation
• Appropriate disinfection of products (liberal amounts of alcohol used, should be left for sufficient amount of time to evaporate)
• Microbiological monitoring
– Finger dabs
– Settle plates (to catch stray particles - settle plates of blood agar)
– Surface testing (on a daily basis, swabs taken and cultured)
– Active air sampling (air is monitored constantly, hand held devices will suck in air and count particles)
Asepsis and GMP
- GMP applies to all aseptic processes
- Must have a system in place to trace patients should a problem be identified
- Documentation kept up to date
- All processes to be validated regularly
What can go wrong?
• Manchester Children’s Incident 1994
– 2 children died after receiving TPN contaminated with Enterobacter cloacae
• Germany Incident 2010
– 3 babies died and 4 critically ill after receiving TPN
contaminated with Enterobacter cloacae
- Giving lines were not changed regularly so bacteria appeared
